diff --git a/Cargo.lock b/Cargo.lock
index c72c7b8481b5b..f02ae7ef6cfa3 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -721,6 +721,13 @@ version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9a21fa21941700a3cd8fcb4091f361a6a712fac632f85d9f487cc892045d55c6"
 
+[[package]]
+name = "coverage_test_macros"
+version = "0.0.0"
+dependencies = [
+ "proc-macro2",
+]
+
 [[package]]
 name = "cpuid-bool"
 version = "0.1.2"
@@ -3922,6 +3929,7 @@ dependencies = [
 name = "rustc_mir"
 version = "0.0.0"
 dependencies = [
+ "coverage_test_macros",
  "either",
  "itertools 0.9.0",
  "polonius-engine",
diff --git a/compiler/rustc_ast_pretty/src/pprust/state.rs b/compiler/rustc_ast_pretty/src/pprust/state.rs
index a566200c33896..958219cbebf3f 100644
--- a/compiler/rustc_ast_pretty/src/pprust/state.rs
+++ b/compiler/rustc_ast_pretty/src/pprust/state.rs
@@ -2327,11 +2327,12 @@ impl<'a> State<'a> {
             self.print_path(path, false, depth);
         }
         self.s.word(">");
-        self.s.word("::");
-        let item_segment = path.segments.last().unwrap();
-        self.print_ident(item_segment.ident);
-        if let Some(ref args) = item_segment.args {
-            self.print_generic_args(args, colons_before_params)
+        for item_segment in &path.segments[qself.position..] {
+            self.s.word("::");
+            self.print_ident(item_segment.ident);
+            if let Some(ref args) = item_segment.args {
+                self.print_generic_args(args, colons_before_params)
+            }
         }
     }
 
diff --git a/compiler/rustc_codegen_llvm/src/back/write.rs b/compiler/rustc_codegen_llvm/src/back/write.rs
index e6acb6860be9e..6237a4c0020eb 100644
--- a/compiler/rustc_codegen_llvm/src/back/write.rs
+++ b/compiler/rustc_codegen_llvm/src/back/write.rs
@@ -925,9 +925,7 @@ unsafe fn embed_bitcode(
         || cgcx.opts.target_triple.triple().starts_with("asmjs")
     {
         // nothing to do here
-    } else if cgcx.opts.target_triple.triple().contains("windows")
-        || cgcx.opts.target_triple.triple().contains("uefi")
-    {
+    } else if cgcx.is_pe_coff {
         let asm = "
             .section .llvmbc,\"n\"
             .section .llvmcmd,\"n\"
diff --git a/compiler/rustc_codegen_ssa/src/back/write.rs b/compiler/rustc_codegen_ssa/src/back/write.rs
index b34bee3358b40..7f2bb7b5bcdaf 100644
--- a/compiler/rustc_codegen_ssa/src/back/write.rs
+++ b/compiler/rustc_codegen_ssa/src/back/write.rs
@@ -307,6 +307,7 @@ pub struct CodegenContext<B: WriteBackendMethods> {
     pub allocator_module_config: Arc<ModuleConfig>,
     pub tm_factory: TargetMachineFactory<B>,
     pub msvc_imps_needed: bool,
+    pub is_pe_coff: bool,
     pub target_pointer_width: u32,
     pub target_arch: String,
     pub debuginfo: config::DebugInfo,
@@ -1022,6 +1023,7 @@ fn start_executing_work<B: ExtraBackendMethods>(
         tm_factory: TargetMachineFactory(backend.target_machine_factory(tcx.sess, ol)),
         total_cgus,
         msvc_imps_needed: msvc_imps_needed(tcx),
+        is_pe_coff: tcx.sess.target.is_like_windows,
         target_pointer_width: tcx.sess.target.pointer_width,
         target_arch: tcx.sess.target.arch.clone(),
         debuginfo: tcx.sess.opts.debuginfo,
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index 06e69a0009b1f..db11746971d18 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -611,6 +611,18 @@ pub struct TyS<'tcx> {
     outer_exclusive_binder: ty::DebruijnIndex,
 }
 
+impl<'tcx> TyS<'tcx> {
+    /// A constructor used only for internal testing.
+    #[allow(rustc::usage_of_ty_tykind)]
+    pub fn make_for_test(
+        kind: TyKind<'tcx>,
+        flags: TypeFlags,
+        outer_exclusive_binder: ty::DebruijnIndex,
+    ) -> TyS<'tcx> {
+        TyS { kind, flags, outer_exclusive_binder }
+    }
+}
+
 // `TyS` is used a lot. Make sure it doesn't unintentionally get bigger.
 #[cfg(target_arch = "x86_64")]
 static_assert_size!(TyS<'_>, 32);
diff --git a/compiler/rustc_mir/Cargo.toml b/compiler/rustc_mir/Cargo.toml
index 487668cfa1109..9bfd1da039120 100644
--- a/compiler/rustc_mir/Cargo.toml
+++ b/compiler/rustc_mir/Cargo.toml
@@ -31,3 +31,6 @@ rustc_ast = { path = "../rustc_ast" }
 rustc_span = { path = "../rustc_span" }
 rustc_apfloat = { path = "../rustc_apfloat" }
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
+
+[dev-dependencies]
+coverage_test_macros = { path = "src/transform/coverage/test_macros" }
diff --git a/compiler/rustc_mir/src/transform/coverage/counters.rs b/compiler/rustc_mir/src/transform/coverage/counters.rs
index d6c2f7f7aaf1d..20f6a16e0f757 100644
--- a/compiler/rustc_mir/src/transform/coverage/counters.rs
+++ b/compiler/rustc_mir/src/transform/coverage/counters.rs
@@ -14,7 +14,7 @@ use rustc_middle::mir::coverage::*;
 
 /// Manages the counter and expression indexes/IDs to generate `CoverageKind` components for MIR
 /// `Coverage` statements.
-pub(crate) struct CoverageCounters {
+pub(super) struct CoverageCounters {
     function_source_hash: u64,
     next_counter_id: u32,
     num_expressions: u32,
@@ -37,7 +37,7 @@ impl CoverageCounters {
         self.debug_counters.enable();
     }
 
-    /// Makes `CoverageKind` `Counter`s and `Expressions` for the `BasicCoverageBlocks` directly or
+    /// Makes `CoverageKind` `Counter`s and `Expressions` for the `BasicCoverageBlock`s directly or
     /// indirectly associated with `CoverageSpans`, and returns additional `Expression`s
     /// representing intermediate values.
     pub fn make_bcb_counters(
@@ -120,7 +120,6 @@ struct BcbCounters<'a> {
     basic_coverage_blocks: &'a mut CoverageGraph,
 }
 
-// FIXME(richkadel): Add unit tests for `BcbCounters` functions/algorithms.
 impl<'a> BcbCounters<'a> {
     fn new(
         coverage_counters: &'a mut CoverageCounters,
diff --git a/compiler/rustc_mir/src/transform/coverage/debug.rs b/compiler/rustc_mir/src/transform/coverage/debug.rs
index ffa795134e257..7f1dc3844b21d 100644
--- a/compiler/rustc_mir/src/transform/coverage/debug.rs
+++ b/compiler/rustc_mir/src/transform/coverage/debug.rs
@@ -127,7 +127,7 @@ pub const NESTED_INDENT: &str = "    ";
 
 const RUSTC_COVERAGE_DEBUG_OPTIONS: &str = "RUSTC_COVERAGE_DEBUG_OPTIONS";
 
-pub(crate) fn debug_options<'a>() -> &'a DebugOptions {
+pub(super) fn debug_options<'a>() -> &'a DebugOptions {
     static DEBUG_OPTIONS: SyncOnceCell<DebugOptions> = SyncOnceCell::new();
 
     &DEBUG_OPTIONS.get_or_init(|| DebugOptions::from_env())
@@ -136,7 +136,7 @@ pub(crate) fn debug_options<'a>() -> &'a DebugOptions {
 /// Parses and maintains coverage-specific debug options captured from the environment variable
 /// "RUSTC_COVERAGE_DEBUG_OPTIONS", if set.
 #[derive(Debug, Clone)]
-pub(crate) struct DebugOptions {
+pub(super) struct DebugOptions {
     pub allow_unused_expressions: bool,
     counter_format: ExpressionFormat,
 }
@@ -250,7 +250,7 @@ impl Default for ExpressionFormat {
 ///
 /// `DebugCounters` supports a recursive rendering of `Expression` counters, so they can be
 /// presented as nested expressions such as `(bcb3 - (bcb0 + bcb1))`.
-pub(crate) struct DebugCounters {
+pub(super) struct DebugCounters {
     some_counters: Option<FxHashMap<ExpressionOperandId, DebugCounter>>,
 }
 
@@ -386,7 +386,7 @@ impl DebugCounter {
 
 /// If enabled, this data structure captures additional debugging information used when generating
 /// a Graphviz (.dot file) representation of the `CoverageGraph`, for debugging purposes.
-pub(crate) struct GraphvizData {
+pub(super) struct GraphvizData {
     some_bcb_to_coverage_spans_with_counters:
         Option<FxHashMap<BasicCoverageBlock, Vec<(CoverageSpan, CoverageKind)>>>,
     some_bcb_to_dependency_counters: Option<FxHashMap<BasicCoverageBlock, Vec<CoverageKind>>>,
@@ -496,7 +496,7 @@ impl GraphvizData {
 /// directly or indirectly, to compute the coverage counts for all `CoverageSpan`s, and any that are
 /// _not_ used are retained in the `unused_expressions` Vec, to be included in debug output (logs
 /// and/or a `CoverageGraph` graphviz output).
-pub(crate) struct UsedExpressions {
+pub(super) struct UsedExpressions {
     some_used_expression_operands:
         Option<FxHashMap<ExpressionOperandId, Vec<InjectedExpressionId>>>,
     some_unused_expressions:
@@ -626,7 +626,7 @@ impl UsedExpressions {
 }
 
 /// Generates the MIR pass `CoverageSpan`-specific spanview dump file.
-pub(crate) fn dump_coverage_spanview(
+pub(super) fn dump_coverage_spanview(
     tcx: TyCtxt<'tcx>,
     mir_body: &mir::Body<'tcx>,
     basic_coverage_blocks: &CoverageGraph,
@@ -666,7 +666,7 @@ fn span_viewables(
 }
 
 /// Generates the MIR pass coverage-specific graphviz dump file.
-pub(crate) fn dump_coverage_graphviz(
+pub(super) fn dump_coverage_graphviz(
     tcx: TyCtxt<'tcx>,
     mir_body: &mir::Body<'tcx>,
     pass_name: &str,
@@ -815,7 +815,7 @@ fn bcb_to_string_sections(
 
 /// Returns a simple string representation of a `TerminatorKind` variant, indenpendent of any
 /// values it might hold.
-pub(crate) fn term_type(kind: &TerminatorKind<'tcx>) -> &'static str {
+pub(super) fn term_type(kind: &TerminatorKind<'tcx>) -> &'static str {
     match kind {
         TerminatorKind::Goto { .. } => "Goto",
         TerminatorKind::SwitchInt { .. } => "SwitchInt",
diff --git a/compiler/rustc_mir/src/transform/coverage/graph.rs b/compiler/rustc_mir/src/transform/coverage/graph.rs
index c2ed2cbb10002..9d375633dcf51 100644
--- a/compiler/rustc_mir/src/transform/coverage/graph.rs
+++ b/compiler/rustc_mir/src/transform/coverage/graph.rs
@@ -17,7 +17,8 @@ const ID_SEPARATOR: &str = ",";
 /// `CoverageKind` counter (to be added by `CoverageCounters::make_bcb_counters`), and an optional
 /// set of additional counters--if needed--to count incoming edges, if there are more than one.
 /// (These "edge counters" are eventually converted into new MIR `BasicBlock`s.)
-pub(crate) struct CoverageGraph {
+#[derive(Debug)]
+pub(super) struct CoverageGraph {
     bcbs: IndexVec<BasicCoverageBlock, BasicCoverageBlockData>,
     bb_to_bcb: IndexVec<BasicBlock, Option<BasicCoverageBlock>>,
     pub successors: IndexVec<BasicCoverageBlock, Vec<BasicCoverageBlock>>,
@@ -275,7 +276,7 @@ impl graph::WithPredecessors for CoverageGraph {
 
 rustc_index::newtype_index! {
     /// A node in the [control-flow graph][CFG] of CoverageGraph.
-    pub(crate) struct BasicCoverageBlock {
+    pub(super) struct BasicCoverageBlock {
         DEBUG_FORMAT = "bcb{}",
     }
 }
@@ -305,7 +306,7 @@ rustc_index::newtype_index! {
 /// queries (`is_dominated_by()`, `predecessors`, `successors`, etc.) have branch (control flow)
 /// significance.
 #[derive(Debug, Clone)]
-pub(crate) struct BasicCoverageBlockData {
+pub(super) struct BasicCoverageBlockData {
     pub basic_blocks: Vec<BasicBlock>,
     pub counter_kind: Option<CoverageKind>,
     edge_from_bcbs: Option<FxHashMap<BasicCoverageBlock, CoverageKind>>,
@@ -431,7 +432,7 @@ impl BasicCoverageBlockData {
 /// the specific branching BCB, representing the edge between the two. The latter case
 /// distinguishes this incoming edge from other incoming edges to the same `target_bcb`.
 #[derive(Clone, Copy, PartialEq, Eq)]
-pub(crate) struct BcbBranch {
+pub(super) struct BcbBranch {
     pub edge_from_bcb: Option<BasicCoverageBlock>,
     pub target_bcb: BasicCoverageBlock,
 }
@@ -498,9 +499,8 @@ fn bcb_filtered_successors<'a, 'tcx>(
 /// Maintains separate worklists for each loop in the BasicCoverageBlock CFG, plus one for the
 /// CoverageGraph outside all loops. This supports traversing the BCB CFG in a way that
 /// ensures a loop is completely traversed before processing Blocks after the end of the loop.
-// FIXME(richkadel): Add unit tests for TraversalContext.
 #[derive(Debug)]
-pub(crate) struct TraversalContext {
+pub(super) struct TraversalContext {
     /// From one or more backedges returning to a loop header.
     pub loop_backedges: Option<(Vec<BasicCoverageBlock>, BasicCoverageBlock)>,
 
@@ -510,7 +510,7 @@ pub(crate) struct TraversalContext {
     pub worklist: Vec<BasicCoverageBlock>,
 }
 
-pub(crate) struct TraverseCoverageGraphWithLoops {
+pub(super) struct TraverseCoverageGraphWithLoops {
     pub backedges: IndexVec<BasicCoverageBlock, Vec<BasicCoverageBlock>>,
     pub context_stack: Vec<TraversalContext>,
     visited: BitSet<BasicCoverageBlock>,
@@ -642,7 +642,7 @@ impl TraverseCoverageGraphWithLoops {
     }
 }
 
-fn find_loop_backedges(
+pub(super) fn find_loop_backedges(
     basic_coverage_blocks: &CoverageGraph,
 ) -> IndexVec<BasicCoverageBlock, Vec<BasicCoverageBlock>> {
     let num_bcbs = basic_coverage_blocks.num_nodes();
diff --git a/compiler/rustc_mir/src/transform/coverage/mod.rs b/compiler/rustc_mir/src/transform/coverage/mod.rs
index c55349239b034..192bb6680e420 100644
--- a/compiler/rustc_mir/src/transform/coverage/mod.rs
+++ b/compiler/rustc_mir/src/transform/coverage/mod.rs
@@ -5,6 +5,9 @@ mod debug;
 mod graph;
 mod spans;
 
+#[cfg(test)]
+mod tests;
+
 use counters::CoverageCounters;
 use graph::{BasicCoverageBlock, BasicCoverageBlockData, CoverageGraph};
 use spans::{CoverageSpan, CoverageSpans};
@@ -31,7 +34,7 @@ use rustc_span::{CharPos, Pos, SourceFile, Span, Symbol};
 
 /// A simple error message wrapper for `coverage::Error`s.
 #[derive(Debug)]
-pub(crate) struct Error {
+struct Error {
     message: String,
 }
 
diff --git a/compiler/rustc_mir/src/transform/coverage/spans.rs b/compiler/rustc_mir/src/transform/coverage/spans.rs
index cda4fc125442f..95c49922262f6 100644
--- a/compiler/rustc_mir/src/transform/coverage/spans.rs
+++ b/compiler/rustc_mir/src/transform/coverage/spans.rs
@@ -17,7 +17,7 @@ use rustc_span::{BytePos, Span, SyntaxContext};
 use std::cmp::Ordering;
 
 #[derive(Debug, Copy, Clone)]
-pub(crate) enum CoverageStatement {
+pub(super) enum CoverageStatement {
     Statement(BasicBlock, Span, usize),
     Terminator(BasicBlock, Span),
 }
@@ -66,7 +66,7 @@ impl CoverageStatement {
 /// or is subsumed by the `Span` associated with this `CoverageSpan`, and it's `BasicBlock`
 /// `is_dominated_by()` the `BasicBlock`s in this `CoverageSpan`.
 #[derive(Debug, Clone)]
-pub(crate) struct CoverageSpan {
+pub(super) struct CoverageSpan {
     pub span: Span,
     pub bcb: BasicCoverageBlock,
     pub coverage_statements: Vec<CoverageStatement>,
@@ -214,7 +214,7 @@ pub struct CoverageSpans<'a, 'tcx> {
 }
 
 impl<'a, 'tcx> CoverageSpans<'a, 'tcx> {
-    pub(crate) fn generate_coverage_spans(
+    pub(super) fn generate_coverage_spans(
         mir_body: &'a mir::Body<'tcx>,
         body_span: Span,
         basic_coverage_blocks: &'a CoverageGraph,
@@ -645,7 +645,10 @@ impl<'a, 'tcx> CoverageSpans<'a, 'tcx> {
     }
 }
 
-fn filtered_statement_span(statement: &'a Statement<'tcx>, body_span: Span) -> Option<Span> {
+pub(super) fn filtered_statement_span(
+    statement: &'a Statement<'tcx>,
+    body_span: Span,
+) -> Option<Span> {
     match statement.kind {
         // These statements have spans that are often outside the scope of the executed source code
         // for their parent `BasicBlock`.
@@ -686,7 +689,10 @@ fn filtered_statement_span(statement: &'a Statement<'tcx>, body_span: Span) -> O
     }
 }
 
-fn filtered_terminator_span(terminator: &'a Terminator<'tcx>, body_span: Span) -> Option<Span> {
+pub(super) fn filtered_terminator_span(
+    terminator: &'a Terminator<'tcx>,
+    body_span: Span,
+) -> Option<Span> {
     match terminator.kind {
         // These terminators have spans that don't positively contribute to computing a reasonable
         // span of actually executed source code. (For example, SwitchInt terminators extracted from
diff --git a/compiler/rustc_mir/src/transform/coverage/test_macros/Cargo.toml b/compiler/rustc_mir/src/transform/coverage/test_macros/Cargo.toml
new file mode 100644
index 0000000000000..a9d6f0c803d2e
--- /dev/null
+++ b/compiler/rustc_mir/src/transform/coverage/test_macros/Cargo.toml
@@ -0,0 +1,12 @@
+[package]
+authors = ["The Rust Project Developers"]
+name = "coverage_test_macros"
+version = "0.0.0"
+edition = "2018"
+
+[lib]
+proc-macro = true
+doctest = false
+
+[dependencies]
+proc-macro2 = "1"
diff --git a/compiler/rustc_mir/src/transform/coverage/test_macros/src/lib.rs b/compiler/rustc_mir/src/transform/coverage/test_macros/src/lib.rs
new file mode 100644
index 0000000000000..3d6095d2738cb
--- /dev/null
+++ b/compiler/rustc_mir/src/transform/coverage/test_macros/src/lib.rs
@@ -0,0 +1,6 @@
+use proc_macro::TokenStream;
+
+#[proc_macro]
+pub fn let_bcb(item: TokenStream) -> TokenStream {
+    format!("let bcb{} = graph::BasicCoverageBlock::from_usize({});", item, item).parse().unwrap()
+}
diff --git a/compiler/rustc_mir/src/transform/coverage/tests.rs b/compiler/rustc_mir/src/transform/coverage/tests.rs
new file mode 100644
index 0000000000000..d36f1b8e5f670
--- /dev/null
+++ b/compiler/rustc_mir/src/transform/coverage/tests.rs
@@ -0,0 +1,714 @@
+//! This crate hosts a selection of "unit tests" for components of the `InstrumentCoverage` MIR
+//! pass.
+//!
+//! The tests construct a few "mock" objects, as needed, to support the `InstrumentCoverage`
+//! functions and algorithms. Mocked objects include instances of `mir::Body`; including
+//! `Terminator`s of various `kind`s, and `Span` objects. Some functions used by or used on
+//! real, runtime versions of these mocked-up objects have constraints (such as cross-thread
+//! limitations) and deep dependencies on other elements of the full Rust compiler (which is
+//! *not* constructed or mocked for these tests).
+//!
+//! Of particular note, attempting to simply print elements of the `mir::Body` with default
+//! `Debug` formatting can fail because some `Debug` format implementations require the
+//! `TyCtxt`, obtained via a static global variable that is *not* set for these tests.
+//! Initializing the global type context is prohibitively complex for the scope and scale of these
+//! tests (essentially requiring initializing the entire compiler).
+//!
+//! Also note, some basic features of `Span` also rely on the `Span`s own "session globals", which
+//! are unrelated to the `TyCtxt` global. Without initializing the `Span` session globals, some
+//! basic, coverage-specific features would be impossible to test, but thankfully initializing these
+//! globals is comparitively simpler. The easiest way is to wrap the test in a closure argument
+//! to: `rustc_span::with_default_session_globals(|| { test_here(); })`.
+
+use super::counters;
+use super::debug;
+use super::graph;
+use super::spans;
+
+use coverage_test_macros::let_bcb;
+
+use rustc_data_structures::graph::WithNumNodes;
+use rustc_data_structures::graph::WithSuccessors;
+use rustc_index::vec::{Idx, IndexVec};
+use rustc_middle::mir::coverage::CoverageKind;
+use rustc_middle::mir::*;
+use rustc_middle::ty::{self, DebruijnIndex, TyS, TypeFlags};
+use rustc_span::{self, BytePos, Pos, Span, DUMMY_SP};
+
+// All `TEMP_BLOCK` targets should be replaced before calling `to_body() -> mir::Body`.
+const TEMP_BLOCK: BasicBlock = BasicBlock::MAX;
+
+fn dummy_ty() -> &'static TyS<'static> {
+    thread_local! {
+        static DUMMY_TYS: &'static TyS<'static> = Box::leak(box TyS::make_for_test(
+            ty::Bool,
+            TypeFlags::empty(),
+            DebruijnIndex::from_usize(0),
+        ));
+    }
+
+    &DUMMY_TYS.with(|tys| *tys)
+}
+
+struct MockBlocks<'tcx> {
+    blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
+    dummy_place: Place<'tcx>,
+    next_local: usize,
+}
+
+impl<'tcx> MockBlocks<'tcx> {
+    fn new() -> Self {
+        Self {
+            blocks: IndexVec::new(),
+            dummy_place: Place { local: RETURN_PLACE, projection: ty::List::empty() },
+            next_local: 0,
+        }
+    }
+
+    fn new_temp(&mut self) -> Local {
+        let index = self.next_local;
+        self.next_local += 1;
+        Local::new(index)
+    }
+
+    fn push(&mut self, kind: TerminatorKind<'tcx>) -> BasicBlock {
+        let next_lo = if let Some(last) = self.blocks.last() {
+            self.blocks[last].terminator().source_info.span.hi()
+        } else {
+            BytePos(1)
+        };
+        let next_hi = next_lo + BytePos(1);
+        self.blocks.push(BasicBlockData {
+            statements: vec![],
+            terminator: Some(Terminator {
+                source_info: SourceInfo::outermost(Span::with_root_ctxt(next_lo, next_hi)),
+                kind,
+            }),
+            is_cleanup: false,
+        })
+    }
+
+    fn link(&mut self, from_block: BasicBlock, to_block: BasicBlock) {
+        match self.blocks[from_block].terminator_mut().kind {
+            TerminatorKind::Assert { ref mut target, .. }
+            | TerminatorKind::Call { destination: Some((_, ref mut target)), .. }
+            | TerminatorKind::Drop { ref mut target, .. }
+            | TerminatorKind::DropAndReplace { ref mut target, .. }
+            | TerminatorKind::FalseEdge { real_target: ref mut target, .. }
+            | TerminatorKind::FalseUnwind { real_target: ref mut target, .. }
+            | TerminatorKind::Goto { ref mut target }
+            | TerminatorKind::InlineAsm { destination: Some(ref mut target), .. }
+            | TerminatorKind::Yield { resume: ref mut target, .. } => *target = to_block,
+            ref invalid => bug!("Invalid from_block: {:?}", invalid),
+        }
+    }
+
+    fn add_block_from(
+        &mut self,
+        some_from_block: Option<BasicBlock>,
+        to_kind: TerminatorKind<'tcx>,
+    ) -> BasicBlock {
+        let new_block = self.push(to_kind);
+        if let Some(from_block) = some_from_block {
+            self.link(from_block, new_block);
+        }
+        new_block
+    }
+
+    fn set_branch(&mut self, switchint: BasicBlock, branch_index: usize, to_block: BasicBlock) {
+        match self.blocks[switchint].terminator_mut().kind {
+            TerminatorKind::SwitchInt { ref mut targets, .. } => {
+                let mut branches = targets.iter().collect::<Vec<_>>();
+                let otherwise = if branch_index == branches.len() {
+                    to_block
+                } else {
+                    let old_otherwise = targets.otherwise();
+                    if branch_index > branches.len() {
+                        branches.push((branches.len() as u128, old_otherwise));
+                        while branches.len() < branch_index {
+                            branches.push((branches.len() as u128, TEMP_BLOCK));
+                        }
+                        to_block
+                    } else {
+                        branches[branch_index] = (branch_index as u128, to_block);
+                        old_otherwise
+                    }
+                };
+                *targets = SwitchTargets::new(branches.into_iter(), otherwise);
+            }
+            ref invalid => bug!("Invalid BasicBlock kind or no to_block: {:?}", invalid),
+        }
+    }
+
+    fn call(&mut self, some_from_block: Option<BasicBlock>) -> BasicBlock {
+        self.add_block_from(
+            some_from_block,
+            TerminatorKind::Call {
+                func: Operand::Copy(self.dummy_place.clone()),
+                args: vec![],
+                destination: Some((self.dummy_place.clone(), TEMP_BLOCK)),
+                cleanup: None,
+                from_hir_call: false,
+                fn_span: DUMMY_SP,
+            },
+        )
+    }
+
+    fn goto(&mut self, some_from_block: Option<BasicBlock>) -> BasicBlock {
+        self.add_block_from(some_from_block, TerminatorKind::Goto { target: TEMP_BLOCK })
+    }
+
+    fn switchint(&mut self, some_from_block: Option<BasicBlock>) -> BasicBlock {
+        let switchint_kind = TerminatorKind::SwitchInt {
+            discr: Operand::Move(Place::from(self.new_temp())),
+            switch_ty: dummy_ty(),
+            targets: SwitchTargets::static_if(0, TEMP_BLOCK, TEMP_BLOCK),
+        };
+        self.add_block_from(some_from_block, switchint_kind)
+    }
+
+    fn return_(&mut self, some_from_block: Option<BasicBlock>) -> BasicBlock {
+        self.add_block_from(some_from_block, TerminatorKind::Return)
+    }
+
+    fn to_body(self) -> Body<'tcx> {
+        Body::new_cfg_only(self.blocks)
+    }
+}
+
+fn debug_basic_blocks(mir_body: &Body<'tcx>) -> String {
+    format!(
+        "{:?}",
+        mir_body
+            .basic_blocks()
+            .iter_enumerated()
+            .map(|(bb, data)| {
+                let term = &data.terminator();
+                let kind = &term.kind;
+                let span = term.source_info.span;
+                let sp = format!("(span:{},{})", span.lo().to_u32(), span.hi().to_u32());
+                match kind {
+                    TerminatorKind::Assert { target, .. }
+                    | TerminatorKind::Call { destination: Some((_, target)), .. }
+                    | TerminatorKind::Drop { target, .. }
+                    | TerminatorKind::DropAndReplace { target, .. }
+                    | TerminatorKind::FalseEdge { real_target: target, .. }
+                    | TerminatorKind::FalseUnwind { real_target: target, .. }
+                    | TerminatorKind::Goto { target }
+                    | TerminatorKind::InlineAsm { destination: Some(target), .. }
+                    | TerminatorKind::Yield { resume: target, .. } => {
+                        format!("{}{:?}:{} -> {:?}", sp, bb, debug::term_type(kind), target)
+                    }
+                    TerminatorKind::SwitchInt { targets, .. } => {
+                        format!("{}{:?}:{} -> {:?}", sp, bb, debug::term_type(kind), targets)
+                    }
+                    _ => format!("{}{:?}:{}", sp, bb, debug::term_type(kind)),
+                }
+            })
+            .collect::<Vec<_>>()
+    )
+}
+
+static PRINT_GRAPHS: bool = false;
+
+fn print_mir_graphviz(name: &str, mir_body: &Body<'_>) {
+    if PRINT_GRAPHS {
+        println!(
+            "digraph {} {{\n{}\n}}",
+            name,
+            mir_body
+                .basic_blocks()
+                .iter_enumerated()
+                .map(|(bb, data)| {
+                    format!(
+                        "    {:?} [label=\"{:?}: {}\"];\n{}",
+                        bb,
+                        bb,
+                        debug::term_type(&data.terminator().kind),
+                        mir_body
+                            .successors(bb)
+                            .map(|successor| { format!("    {:?} -> {:?};", bb, successor) })
+                            .collect::<Vec<_>>()
+                            .join("\n")
+                    )
+                })
+                .collect::<Vec<_>>()
+                .join("\n")
+        );
+    }
+}
+
+fn print_coverage_graphviz(
+    name: &str,
+    mir_body: &Body<'_>,
+    basic_coverage_blocks: &graph::CoverageGraph,
+) {
+    if PRINT_GRAPHS {
+        println!(
+            "digraph {} {{\n{}\n}}",
+            name,
+            basic_coverage_blocks
+                .iter_enumerated()
+                .map(|(bcb, bcb_data)| {
+                    format!(
+                        "    {:?} [label=\"{:?}: {}\"];\n{}",
+                        bcb,
+                        bcb,
+                        debug::term_type(&bcb_data.terminator(mir_body).kind),
+                        basic_coverage_blocks
+                            .successors(bcb)
+                            .map(|successor| { format!("    {:?} -> {:?};", bcb, successor) })
+                            .collect::<Vec<_>>()
+                            .join("\n")
+                    )
+                })
+                .collect::<Vec<_>>()
+                .join("\n")
+        );
+    }
+}
+
+/// Create a mock `Body` with a simple flow.
+fn goto_switchint() -> Body<'a> {
+    let mut blocks = MockBlocks::new();
+    let start = blocks.call(None);
+    let goto = blocks.goto(Some(start));
+    let switchint = blocks.switchint(Some(goto));
+    let then_call = blocks.call(None);
+    let else_call = blocks.call(None);
+    blocks.set_branch(switchint, 0, then_call);
+    blocks.set_branch(switchint, 1, else_call);
+    blocks.return_(Some(then_call));
+    blocks.return_(Some(else_call));
+
+    let mir_body = blocks.to_body();
+    print_mir_graphviz("mir_goto_switchint", &mir_body);
+    /* Graphviz character plots created using: `graph-easy --as=boxart`:
+                        ┌────────────────┐
+                        │   bb0: Call    │
+                        └────────────────┘
+                          │
+                          │
+                          ▼
+                        ┌────────────────┐
+                        │   bb1: Goto    │
+                        └────────────────┘
+                          │
+                          │
+                          ▼
+    ┌─────────────┐     ┌────────────────┐
+    │  bb4: Call  │ ◀── │ bb2: SwitchInt │
+    └─────────────┘     └────────────────┘
+      │                   │
+      │                   │
+      ▼                   ▼
+    ┌─────────────┐     ┌────────────────┐
+    │ bb6: Return │     │   bb3: Call    │
+    └─────────────┘     └────────────────┘
+                          │
+                          │
+                          ▼
+                        ┌────────────────┐
+                        │  bb5: Return   │
+                        └────────────────┘
+    */
+    mir_body
+}
+
+macro_rules! assert_successors {
+    ($basic_coverage_blocks:ident, $i:ident, [$($successor:ident),*]) => {
+        let mut successors = $basic_coverage_blocks.successors[$i].clone();
+        successors.sort_unstable();
+        assert_eq!(successors, vec![$($successor),*]);
+    }
+}
+
+#[test]
+fn test_covgraph_goto_switchint() {
+    let mir_body = goto_switchint();
+    if false {
+        println!("basic_blocks = {}", debug_basic_blocks(&mir_body));
+    }
+    let basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body);
+    print_coverage_graphviz("covgraph_goto_switchint ", &mir_body, &basic_coverage_blocks);
+    /*
+    ┌──────────────┐     ┌─────────────────┐
+    │ bcb2: Return │ ◀── │ bcb0: SwitchInt │
+    └──────────────┘     └─────────────────┘
+                           │
+                           │
+                           ▼
+                         ┌─────────────────┐
+                         │  bcb1: Return   │
+                         └─────────────────┘
+    */
+    assert_eq!(
+        basic_coverage_blocks.num_nodes(),
+        3,
+        "basic_coverage_blocks: {:?}",
+        basic_coverage_blocks.iter_enumerated().collect::<Vec<_>>()
+    );
+
+    let_bcb!(0);
+    let_bcb!(1);
+    let_bcb!(2);
+
+    assert_successors!(basic_coverage_blocks, bcb0, [bcb1, bcb2]);
+    assert_successors!(basic_coverage_blocks, bcb1, []);
+    assert_successors!(basic_coverage_blocks, bcb2, []);
+}
+
+/// Create a mock `Body` with a loop.
+fn switchint_then_loop_else_return() -> Body<'a> {
+    let mut blocks = MockBlocks::new();
+    let start = blocks.call(None);
+    let switchint = blocks.switchint(Some(start));
+    let then_call = blocks.call(None);
+    blocks.set_branch(switchint, 0, then_call);
+    let backedge_goto = blocks.goto(Some(then_call));
+    blocks.link(backedge_goto, switchint);
+    let else_return = blocks.return_(None);
+    blocks.set_branch(switchint, 1, else_return);
+
+    let mir_body = blocks.to_body();
+    print_mir_graphviz("mir_switchint_then_loop_else_return", &mir_body);
+    /*
+                        ┌────────────────┐
+                        │   bb0: Call    │
+                        └────────────────┘
+                          │
+                          │
+                          ▼
+    ┌─────────────┐     ┌────────────────┐
+    │ bb4: Return │ ◀── │ bb1: SwitchInt │ ◀┐
+    └─────────────┘     └────────────────┘  │
+                          │                 │
+                          │                 │
+                          ▼                 │
+                        ┌────────────────┐  │
+                        │   bb2: Call    │  │
+                        └────────────────┘  │
+                          │                 │
+                          │                 │
+                          ▼                 │
+                        ┌────────────────┐  │
+                        │   bb3: Goto    │ ─┘
+                        └────────────────┘
+    */
+    mir_body
+}
+
+#[test]
+fn test_covgraph_switchint_then_loop_else_return() {
+    let mir_body = switchint_then_loop_else_return();
+    let basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body);
+    print_coverage_graphviz(
+        "covgraph_switchint_then_loop_else_return",
+        &mir_body,
+        &basic_coverage_blocks,
+    );
+    /*
+                       ┌─────────────────┐
+                       │   bcb0: Call    │
+                       └─────────────────┘
+                         │
+                         │
+                         ▼
+    ┌────────────┐     ┌─────────────────┐
+    │ bcb3: Goto │ ◀── │ bcb1: SwitchInt │ ◀┐
+    └────────────┘     └─────────────────┘  │
+      │                  │                  │
+      │                  │                  │
+      │                  ▼                  │
+      │                ┌─────────────────┐  │
+      │                │  bcb2: Return   │  │
+      │                └─────────────────┘  │
+      │                                     │
+      └─────────────────────────────────────┘
+    */
+    assert_eq!(
+        basic_coverage_blocks.num_nodes(),
+        4,
+        "basic_coverage_blocks: {:?}",
+        basic_coverage_blocks.iter_enumerated().collect::<Vec<_>>()
+    );
+
+    let_bcb!(0);
+    let_bcb!(1);
+    let_bcb!(2);
+    let_bcb!(3);
+
+    assert_successors!(basic_coverage_blocks, bcb0, [bcb1]);
+    assert_successors!(basic_coverage_blocks, bcb1, [bcb2, bcb3]);
+    assert_successors!(basic_coverage_blocks, bcb2, []);
+    assert_successors!(basic_coverage_blocks, bcb3, [bcb1]);
+}
+
+/// Create a mock `Body` with nested loops.
+fn switchint_loop_then_inner_loop_else_break() -> Body<'a> {
+    let mut blocks = MockBlocks::new();
+    let start = blocks.call(None);
+    let switchint = blocks.switchint(Some(start));
+    let then_call = blocks.call(None);
+    blocks.set_branch(switchint, 0, then_call);
+    let else_return = blocks.return_(None);
+    blocks.set_branch(switchint, 1, else_return);
+
+    let inner_start = blocks.call(Some(then_call));
+    let inner_switchint = blocks.switchint(Some(inner_start));
+    let inner_then_call = blocks.call(None);
+    blocks.set_branch(inner_switchint, 0, inner_then_call);
+    let inner_backedge_goto = blocks.goto(Some(inner_then_call));
+    blocks.link(inner_backedge_goto, inner_switchint);
+    let inner_else_break_goto = blocks.goto(None);
+    blocks.set_branch(inner_switchint, 1, inner_else_break_goto);
+
+    let backedge_goto = blocks.goto(Some(inner_else_break_goto));
+    blocks.link(backedge_goto, switchint);
+
+    let mir_body = blocks.to_body();
+    print_mir_graphviz("mir_switchint_loop_then_inner_loop_else_break", &mir_body);
+    /*
+                        ┌────────────────┐
+                        │   bb0: Call    │
+                        └────────────────┘
+                          │
+                          │
+                          ▼
+    ┌─────────────┐     ┌────────────────┐
+    │ bb3: Return │ ◀── │ bb1: SwitchInt │ ◀─────┐
+    └─────────────┘     └────────────────┘       │
+                          │                      │
+                          │                      │
+                          ▼                      │
+                        ┌────────────────┐       │
+                        │   bb2: Call    │       │
+                        └────────────────┘       │
+                          │                      │
+                          │                      │
+                          ▼                      │
+                        ┌────────────────┐       │
+                        │   bb4: Call    │       │
+                        └────────────────┘       │
+                          │                      │
+                          │                      │
+                          ▼                      │
+    ┌─────────────┐     ┌────────────────┐       │
+    │  bb8: Goto  │ ◀── │ bb5: SwitchInt │ ◀┐    │
+    └─────────────┘     └────────────────┘  │    │
+      │                   │                 │    │
+      │                   │                 │    │
+      ▼                   ▼                 │    │
+    ┌─────────────┐     ┌────────────────┐  │    │
+    │  bb9: Goto  │ ─┐  │   bb6: Call    │  │    │
+    └─────────────┘  │  └────────────────┘  │    │
+                     │    │                 │    │
+                     │    │                 │    │
+                     │    ▼                 │    │
+                     │  ┌────────────────┐  │    │
+                     │  │   bb7: Goto    │ ─┘    │
+                     │  └────────────────┘       │
+                     │                           │
+                     └───────────────────────────┘
+    */
+    mir_body
+}
+
+#[test]
+fn test_covgraph_switchint_loop_then_inner_loop_else_break() {
+    let mir_body = switchint_loop_then_inner_loop_else_break();
+    let basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body);
+    print_coverage_graphviz(
+        "covgraph_switchint_loop_then_inner_loop_else_break",
+        &mir_body,
+        &basic_coverage_blocks,
+    );
+    /*
+                         ┌─────────────────┐
+                         │   bcb0: Call    │
+                         └─────────────────┘
+                           │
+                           │
+                           ▼
+    ┌──────────────┐     ┌─────────────────┐
+    │ bcb2: Return │ ◀── │ bcb1: SwitchInt │ ◀┐
+    └──────────────┘     └─────────────────┘  │
+                           │                  │
+                           │                  │
+                           ▼                  │
+                         ┌─────────────────┐  │
+                         │   bcb3: Call    │  │
+                         └─────────────────┘  │
+                           │                  │
+                           │                  │
+                           ▼                  │
+    ┌──────────────┐     ┌─────────────────┐  │
+    │  bcb6: Goto  │ ◀── │ bcb4: SwitchInt │ ◀┼────┐
+    └──────────────┘     └─────────────────┘  │    │
+      │                    │                  │    │
+      │                    │                  │    │
+      │                    ▼                  │    │
+      │                  ┌─────────────────┐  │    │
+      │                  │   bcb5: Goto    │ ─┘    │
+      │                  └─────────────────┘       │
+      │                                            │
+      └────────────────────────────────────────────┘
+    */
+    assert_eq!(
+        basic_coverage_blocks.num_nodes(),
+        7,
+        "basic_coverage_blocks: {:?}",
+        basic_coverage_blocks.iter_enumerated().collect::<Vec<_>>()
+    );
+
+    let_bcb!(0);
+    let_bcb!(1);
+    let_bcb!(2);
+    let_bcb!(3);
+    let_bcb!(4);
+    let_bcb!(5);
+    let_bcb!(6);
+
+    assert_successors!(basic_coverage_blocks, bcb0, [bcb1]);
+    assert_successors!(basic_coverage_blocks, bcb1, [bcb2, bcb3]);
+    assert_successors!(basic_coverage_blocks, bcb2, []);
+    assert_successors!(basic_coverage_blocks, bcb3, [bcb4]);
+    assert_successors!(basic_coverage_blocks, bcb4, [bcb5, bcb6]);
+    assert_successors!(basic_coverage_blocks, bcb5, [bcb1]);
+    assert_successors!(basic_coverage_blocks, bcb6, [bcb4]);
+}
+
+#[test]
+fn test_find_loop_backedges_none() {
+    let mir_body = goto_switchint();
+    let basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body);
+    if false {
+        println!(
+            "basic_coverage_blocks = {:?}",
+            basic_coverage_blocks.iter_enumerated().collect::<Vec<_>>()
+        );
+        println!("successors = {:?}", basic_coverage_blocks.successors);
+    }
+    let backedges = graph::find_loop_backedges(&basic_coverage_blocks);
+    assert_eq!(
+        backedges.iter_enumerated().map(|(_bcb, backedges)| backedges.len()).sum::<usize>(),
+        0,
+        "backedges: {:?}",
+        backedges
+    );
+}
+
+#[test]
+fn test_find_loop_backedges_one() {
+    let mir_body = switchint_then_loop_else_return();
+    let basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body);
+    let backedges = graph::find_loop_backedges(&basic_coverage_blocks);
+    assert_eq!(
+        backedges.iter_enumerated().map(|(_bcb, backedges)| backedges.len()).sum::<usize>(),
+        1,
+        "backedges: {:?}",
+        backedges
+    );
+
+    let_bcb!(1);
+    let_bcb!(3);
+
+    assert_eq!(backedges[bcb1], vec![bcb3]);
+}
+
+#[test]
+fn test_find_loop_backedges_two() {
+    let mir_body = switchint_loop_then_inner_loop_else_break();
+    let basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body);
+    let backedges = graph::find_loop_backedges(&basic_coverage_blocks);
+    assert_eq!(
+        backedges.iter_enumerated().map(|(_bcb, backedges)| backedges.len()).sum::<usize>(),
+        2,
+        "backedges: {:?}",
+        backedges
+    );
+
+    let_bcb!(1);
+    let_bcb!(4);
+    let_bcb!(5);
+    let_bcb!(6);
+
+    assert_eq!(backedges[bcb1], vec![bcb5]);
+    assert_eq!(backedges[bcb4], vec![bcb6]);
+}
+
+#[test]
+fn test_traverse_coverage_with_loops() {
+    let mir_body = switchint_loop_then_inner_loop_else_break();
+    let basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body);
+    let mut traversed_in_order = Vec::new();
+    let mut traversal = graph::TraverseCoverageGraphWithLoops::new(&basic_coverage_blocks);
+    while let Some(bcb) = traversal.next(&basic_coverage_blocks) {
+        traversed_in_order.push(bcb);
+    }
+
+    let_bcb!(6);
+
+    // bcb0 is visited first. Then bcb1 starts the first loop, and all remaining nodes, *except*
+    // bcb6 are inside the first loop.
+    assert_eq!(
+        *traversed_in_order.last().expect("should have elements"),
+        bcb6,
+        "bcb6 should not be visited until all nodes inside the first loop have been visited"
+    );
+}
+
+fn synthesize_body_span_from_terminators(mir_body: &Body<'_>) -> Span {
+    let mut some_span: Option<Span> = None;
+    for (_, data) in mir_body.basic_blocks().iter_enumerated() {
+        let term_span = data.terminator().source_info.span;
+        if let Some(span) = some_span.as_mut() {
+            *span = span.to(term_span);
+        } else {
+            some_span = Some(term_span)
+        }
+    }
+    some_span.expect("body must have at least one BasicBlock")
+}
+
+#[test]
+fn test_make_bcb_counters() {
+    rustc_span::with_default_session_globals(|| {
+        let mir_body = goto_switchint();
+        let body_span = synthesize_body_span_from_terminators(&mir_body);
+        let mut basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body);
+        let mut coverage_spans = Vec::new();
+        for (bcb, data) in basic_coverage_blocks.iter_enumerated() {
+            if let Some(span) =
+                spans::filtered_terminator_span(data.terminator(&mir_body), body_span)
+            {
+                coverage_spans.push(spans::CoverageSpan::for_terminator(span, bcb, data.last_bb()));
+            }
+        }
+        let mut coverage_counters = counters::CoverageCounters::new(0);
+        let intermediate_expressions = coverage_counters
+            .make_bcb_counters(&mut basic_coverage_blocks, &coverage_spans)
+            .expect("should be Ok");
+        assert_eq!(intermediate_expressions.len(), 0);
+
+        let_bcb!(1);
+        assert_eq!(
+            1, // coincidentally, bcb1 has a `Counter` with id = 1
+            match basic_coverage_blocks[bcb1].counter().expect("should have a counter") {
+                CoverageKind::Counter { id, .. } => id,
+                _ => panic!("expected a Counter"),
+            }
+            .as_u32()
+        );
+
+        let_bcb!(2);
+        assert_eq!(
+            2, // coincidentally, bcb2 has a `Counter` with id = 2
+            match basic_coverage_blocks[bcb2].counter().expect("should have a counter") {
+                CoverageKind::Counter { id, .. } => id,
+                _ => panic!("expected a Counter"),
+            }
+            .as_u32()
+        );
+    });
+}
diff --git a/compiler/rustc_mir/src/transform/inline.rs b/compiler/rustc_mir/src/transform/inline.rs
index 7737672dbde66..aae98f5b6d8d6 100644
--- a/compiler/rustc_mir/src/transform/inline.rs
+++ b/compiler/rustc_mir/src/transform/inline.rs
@@ -7,6 +7,7 @@ use rustc_index::vec::Idx;
 use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs};
 use rustc_middle::mir::visit::*;
 use rustc_middle::mir::*;
+use rustc_middle::ty::subst::Subst;
 use rustc_middle::ty::{self, ConstKind, Instance, InstanceDef, ParamEnv, Ty, TyCtxt};
 use rustc_span::{hygiene::ExpnKind, ExpnData, Span};
 use rustc_target::spec::abi::Abi;
@@ -28,6 +29,7 @@ pub struct Inline;
 #[derive(Copy, Clone, Debug)]
 struct CallSite<'tcx> {
     callee: Instance<'tcx>,
+    fn_sig: ty::PolyFnSig<'tcx>,
     block: BasicBlock,
     target: Option<BasicBlock>,
     source_info: SourceInfo,
@@ -173,22 +175,23 @@ impl Inliner<'tcx> {
 
         // Only consider direct calls to functions
         let terminator = bb_data.terminator();
-        if let TerminatorKind::Call { func: ref op, ref destination, .. } = terminator.kind {
-            if let ty::FnDef(callee_def_id, substs) = *op.ty(caller_body, self.tcx).kind() {
-                // To resolve an instance its substs have to be fully normalized, so
-                // we do this here.
-                let normalized_substs = self.tcx.normalize_erasing_regions(self.param_env, substs);
+        if let TerminatorKind::Call { ref func, ref destination, .. } = terminator.kind {
+            let func_ty = func.ty(caller_body, self.tcx);
+            if let ty::FnDef(def_id, substs) = *func_ty.kind() {
+                // To resolve an instance its substs have to be fully normalized.
+                let substs = self.tcx.normalize_erasing_regions(self.param_env, substs);
                 let callee =
-                    Instance::resolve(self.tcx, self.param_env, callee_def_id, normalized_substs)
-                        .ok()
-                        .flatten()?;
+                    Instance::resolve(self.tcx, self.param_env, def_id, substs).ok().flatten()?;
 
                 if let InstanceDef::Virtual(..) | InstanceDef::Intrinsic(_) = callee.def {
                     return None;
                 }
 
+                let fn_sig = self.tcx.fn_sig(def_id).subst(self.tcx, substs);
+
                 return Some(CallSite {
                     callee,
+                    fn_sig,
                     block: bb,
                     target: destination.map(|(_, target)| target),
                     source_info: terminator.source_info,
@@ -203,9 +206,8 @@ impl Inliner<'tcx> {
         debug!("should_inline({:?})", callsite);
         let tcx = self.tcx;
 
-        // Cannot inline generators which haven't been transformed yet
-        if callee_body.yield_ty.is_some() {
-            debug!("    yield ty present - not inlining");
+        if callsite.fn_sig.c_variadic() {
+            debug!("callee is variadic - not inlining");
             return false;
         }
 
@@ -218,11 +220,7 @@ impl Inliner<'tcx> {
             return false;
         }
 
-        let self_no_sanitize =
-            self.codegen_fn_attrs.no_sanitize & self.tcx.sess.opts.debugging_opts.sanitizer;
-        let callee_no_sanitize =
-            codegen_fn_attrs.no_sanitize & self.tcx.sess.opts.debugging_opts.sanitizer;
-        if self_no_sanitize != callee_no_sanitize {
+        if self.codegen_fn_attrs.no_sanitize != codegen_fn_attrs.no_sanitize {
             debug!("`callee has incompatible no_sanitize attribute - not inlining");
             return false;
         }
@@ -256,9 +254,9 @@ impl Inliner<'tcx> {
             self.tcx.sess.opts.debugging_opts.inline_mir_threshold
         };
 
-        // Significantly lower the threshold for inlining cold functions
         if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::COLD) {
-            threshold /= 5;
+            debug!("#[cold] present - not inlining");
+            return false;
         }
 
         // Give a bonus functions with a small number of blocks,
@@ -447,7 +445,7 @@ impl Inliner<'tcx> {
                 };
 
                 // Copy the arguments if needed.
-                let args: Vec<_> = self.make_call_args(args, &callsite, caller_body);
+                let args: Vec<_> = self.make_call_args(args, &callsite, caller_body, &callee_body);
 
                 let mut integrator = Integrator {
                     args: &args,
@@ -528,6 +526,7 @@ impl Inliner<'tcx> {
         args: Vec<Operand<'tcx>>,
         callsite: &CallSite<'tcx>,
         caller_body: &mut Body<'tcx>,
+        callee_body: &Body<'tcx>,
     ) -> Vec<Local> {
         let tcx = self.tcx;
 
@@ -554,9 +553,7 @@ impl Inliner<'tcx> {
         //     tmp2 = tuple_tmp.2
         //
         // and the vector is `[closure_ref, tmp0, tmp1, tmp2]`.
-        // FIXME(eddyb) make this check for `"rust-call"` ABI combined with
-        // `callee_body.spread_arg == None`, instead of special-casing closures.
-        if tcx.is_closure(callsite.callee.def_id()) {
+        if callsite.fn_sig.abi() == Abi::RustCall && callee_body.spread_arg.is_none() {
             let mut args = args.into_iter();
             let self_ = self.create_temp_if_necessary(args.next().unwrap(), callsite, caller_body);
             let tuple = self.create_temp_if_necessary(args.next().unwrap(), callsite, caller_body);
diff --git a/compiler/rustc_mir/src/transform/validate.rs b/compiler/rustc_mir/src/transform/validate.rs
index e1e6e71acb5a8..876ecee80c6a1 100644
--- a/compiler/rustc_mir/src/transform/validate.rs
+++ b/compiler/rustc_mir/src/transform/validate.rs
@@ -38,7 +38,9 @@ pub struct Validator {
 impl<'tcx> MirPass<'tcx> for Validator {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         let def_id = body.source.def_id();
-        let param_env = tcx.param_env(def_id);
+        // We need to param_env_reveal_all_normalized, as some optimizations
+        // change types in ways that require unfolding opaque types.
+        let param_env = tcx.param_env_reveal_all_normalized(def_id);
         let mir_phase = self.mir_phase;
 
         let always_live_locals = AlwaysLiveLocals::new(body);
@@ -79,7 +81,6 @@ pub fn equal_up_to_regions(
     }
 
     // Normalize lifetimes away on both sides, then compare.
-    let param_env = param_env.with_reveal_all_normalized(tcx);
     let normalize = |ty: Ty<'tcx>| {
         tcx.normalize_erasing_regions(
             param_env,
@@ -167,17 +168,14 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
             return true;
         }
         // Normalize projections and things like that.
-        // FIXME: We need to reveal_all, as some optimizations change types in ways
-        // that require unfolding opaque types.
-        let param_env = self.param_env.with_reveal_all_normalized(self.tcx);
-        let src = self.tcx.normalize_erasing_regions(param_env, src);
-        let dest = self.tcx.normalize_erasing_regions(param_env, dest);
+        let src = self.tcx.normalize_erasing_regions(self.param_env, src);
+        let dest = self.tcx.normalize_erasing_regions(self.param_env, dest);
 
         // Type-changing assignments can happen when subtyping is used. While
         // all normal lifetimes are erased, higher-ranked types with their
         // late-bound lifetimes are still around and can lead to type
         // differences. So we compare ignoring lifetimes.
-        equal_up_to_regions(self.tcx, param_env, src, dest)
+        equal_up_to_regions(self.tcx, self.param_env, src, dest)
     }
 }
 
@@ -358,6 +356,7 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
             }
             TerminatorKind::Call { func, args, destination, cleanup, .. } => {
                 let func_ty = func.ty(&self.body.local_decls, self.tcx);
+                let func_ty = self.tcx.normalize_erasing_regions(self.param_env, func_ty);
                 match func_ty.kind() {
                     ty::FnPtr(..) | ty::FnDef(..) => {}
                     _ => self.fail(
diff --git a/compiler/rustc_parse/src/parser/mod.rs b/compiler/rustc_parse/src/parser/mod.rs
index da1c54e88b5e2..40aa2db58c720 100644
--- a/compiler/rustc_parse/src/parser/mod.rs
+++ b/compiler/rustc_parse/src/parser/mod.rs
@@ -1180,8 +1180,7 @@ impl<'a> Parser<'a> {
     /// Records all tokens consumed by the provided callback,
     /// including the current token. These tokens are collected
     /// into a `LazyTokenStream`, and returned along with the result
-    /// of the callback. The returned `LazyTokenStream` will be `None`
-    /// if not tokens were captured.
+    /// of the callback.
     ///
     /// Note: If your callback consumes an opening delimiter
     /// (including the case where you call `collect_tokens`
@@ -1203,17 +1202,14 @@ impl<'a> Parser<'a> {
 
         let ret = f(self)?;
 
-        // We didn't capture any tokens
-        let num_calls = self.token_cursor.num_next_calls - cursor_snapshot.num_next_calls;
-        if num_calls == 0 {
-            return Ok((ret, None));
-        }
-
         // Produces a `TokenStream` on-demand. Using `cursor_snapshot`
         // and `num_calls`, we can reconstruct the `TokenStream` seen
         // by the callback. This allows us to avoid producing a `TokenStream`
         // if it is never needed - for example, a captured `macro_rules!`
         // argument that is never passed to a proc macro.
+        // In practice token stream creation happens rarely compared to
+        // calls to `collect_tokens` (see some statistics in #78736),
+        // so we are doing as little up-front work as possible.
         //
         // This also makes `Parser` very cheap to clone, since
         // there is no intermediate collection buffer to clone.
@@ -1247,8 +1243,8 @@ impl<'a> Parser<'a> {
 
         let lazy_impl = LazyTokenStreamImpl {
             start_token,
+            num_calls: self.token_cursor.num_next_calls - cursor_snapshot.num_next_calls,
             cursor_snapshot,
-            num_calls,
             desugar_doc_comments: self.desugar_doc_comments,
         };
         Ok((ret, Some(LazyTokenStream::new(lazy_impl))))
diff --git a/compiler/rustc_save_analysis/src/sig.rs b/compiler/rustc_save_analysis/src/sig.rs
index 1bf8160e4c384..2f82d0546ba98 100644
--- a/compiler/rustc_save_analysis/src/sig.rs
+++ b/compiler/rustc_save_analysis/src/sig.rs
@@ -21,7 +21,7 @@
 // references.
 //
 // Signatures do not include visibility info. I'm not sure if this is a feature
-// or an ommission (FIXME).
+// or an omission (FIXME).
 //
 // FIXME where clauses need implementing, defs/refs in generics are mostly missing.
 
@@ -677,7 +677,7 @@ impl<'hir> Sig for hir::Variant<'hir> {
         let mut text = self.ident.to_string();
         match self.data {
             hir::VariantData::Struct(fields, r) => {
-                let id = parent_id.unwrap();
+                let id = parent_id.ok_or("Missing id for Variant's parent")?;
                 let name_def = SigElement {
                     id: id_from_hir_id(id, scx),
                     start: offset,
diff --git a/compiler/rustc_target/src/spec/aarch64_unknown_none.rs b/compiler/rustc_target/src/spec/aarch64_unknown_none.rs
index d0ad45153d677..c9f622820dea7 100644
--- a/compiler/rustc_target/src/spec/aarch64_unknown_none.rs
+++ b/compiler/rustc_target/src/spec/aarch64_unknown_none.rs
@@ -10,7 +10,6 @@ use super::{LinkerFlavor, LldFlavor, PanicStrategy, RelocModel, Target, TargetOp
 
 pub fn target() -> Target {
     let opts = TargetOptions {
-        vendor: String::new(),
         linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
         linker: Some("rust-lld".to_owned()),
         features: "+strict-align,+neon,+fp-armv8".to_string(),
diff --git a/compiler/rustc_target/src/spec/aarch64_unknown_none_softfloat.rs b/compiler/rustc_target/src/spec/aarch64_unknown_none_softfloat.rs
index 41bd2182905c9..0811871c993aa 100644
--- a/compiler/rustc_target/src/spec/aarch64_unknown_none_softfloat.rs
+++ b/compiler/rustc_target/src/spec/aarch64_unknown_none_softfloat.rs
@@ -10,7 +10,6 @@ use super::{LinkerFlavor, LldFlavor, PanicStrategy, RelocModel, Target, TargetOp
 
 pub fn target() -> Target {
     let opts = TargetOptions {
-        vendor: String::new(),
         linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
         linker: Some("rust-lld".to_owned()),
         features: "+strict-align,-neon,-fp-armv8".to_string(),
diff --git a/compiler/rustc_target/src/spec/armebv7r_none_eabi.rs b/compiler/rustc_target/src/spec/armebv7r_none_eabi.rs
index 3685630572371..c6586b79b87f8 100644
--- a/compiler/rustc_target/src/spec/armebv7r_none_eabi.rs
+++ b/compiler/rustc_target/src/spec/armebv7r_none_eabi.rs
@@ -12,7 +12,6 @@ pub fn target() -> Target {
 
         options: TargetOptions {
             endian: "big".to_string(),
-            vendor: String::new(),
             linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
             executables: true,
             linker: Some("rust-lld".to_owned()),
diff --git a/compiler/rustc_target/src/spec/armebv7r_none_eabihf.rs b/compiler/rustc_target/src/spec/armebv7r_none_eabihf.rs
index 2ff3c8950c483..e3d4397f6123f 100644
--- a/compiler/rustc_target/src/spec/armebv7r_none_eabihf.rs
+++ b/compiler/rustc_target/src/spec/armebv7r_none_eabihf.rs
@@ -12,7 +12,6 @@ pub fn target() -> Target {
 
         options: TargetOptions {
             endian: "big".to_string(),
-            vendor: String::new(),
             linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
             executables: true,
             linker: Some("rust-lld".to_owned()),
diff --git a/compiler/rustc_target/src/spec/armv7a_none_eabi.rs b/compiler/rustc_target/src/spec/armv7a_none_eabi.rs
index 742b403cff90c..74deab0191652 100644
--- a/compiler/rustc_target/src/spec/armv7a_none_eabi.rs
+++ b/compiler/rustc_target/src/spec/armv7a_none_eabi.rs
@@ -10,9 +10,6 @@
 // bare-metal binaries (the `gcc` linker has the advantage that it knows where C
 // libraries and crt*.o are but it's not much of an advantage here); LLD is also
 // faster
-// - `os` set to `none`. rationale: matches `thumb` targets
-// - `env` and `vendor` are set to an empty string. rationale: matches `thumb`
-// targets
 // - `panic_strategy` set to `abort`. rationale: matches `thumb` targets
 // - `relocation-model` set to `static`; also no PIE, no relro and no dynamic
 // linking. rationale: matches `thumb` targets
@@ -21,7 +18,6 @@ use super::{LinkerFlavor, LldFlavor, PanicStrategy, RelocModel, Target, TargetOp
 
 pub fn target() -> Target {
     let opts = TargetOptions {
-        vendor: String::new(),
         linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
         linker: Some("rust-lld".to_owned()),
         features: "+v7,+thumb2,+soft-float,-neon,+strict-align".to_string(),
diff --git a/compiler/rustc_target/src/spec/armv7a_none_eabihf.rs b/compiler/rustc_target/src/spec/armv7a_none_eabihf.rs
index b9cda18d6b46f..c5c720f5fbde4 100644
--- a/compiler/rustc_target/src/spec/armv7a_none_eabihf.rs
+++ b/compiler/rustc_target/src/spec/armv7a_none_eabihf.rs
@@ -9,7 +9,6 @@ use super::{LinkerFlavor, LldFlavor, PanicStrategy, RelocModel, Target, TargetOp
 
 pub fn target() -> Target {
     let opts = TargetOptions {
-        vendor: String::new(),
         linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
         linker: Some("rust-lld".to_owned()),
         features: "+v7,+vfp3,-d32,+thumb2,-neon,+strict-align".to_string(),
diff --git a/compiler/rustc_target/src/spec/armv7r_none_eabi.rs b/compiler/rustc_target/src/spec/armv7r_none_eabi.rs
index 440c2434907be..3f49bd8786937 100644
--- a/compiler/rustc_target/src/spec/armv7r_none_eabi.rs
+++ b/compiler/rustc_target/src/spec/armv7r_none_eabi.rs
@@ -11,7 +11,6 @@ pub fn target() -> Target {
         arch: "arm".to_string(),
 
         options: TargetOptions {
-            vendor: String::new(),
             linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
             executables: true,
             linker: Some("rust-lld".to_owned()),
diff --git a/compiler/rustc_target/src/spec/armv7r_none_eabihf.rs b/compiler/rustc_target/src/spec/armv7r_none_eabihf.rs
index c1bf332a72ddf..9b2e8a8058fe7 100644
--- a/compiler/rustc_target/src/spec/armv7r_none_eabihf.rs
+++ b/compiler/rustc_target/src/spec/armv7r_none_eabihf.rs
@@ -11,7 +11,6 @@ pub fn target() -> Target {
         arch: "arm".to_string(),
 
         options: TargetOptions {
-            vendor: String::new(),
             linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
             executables: true,
             linker: Some("rust-lld".to_owned()),
diff --git a/compiler/rustc_target/src/spec/avr_gnu_base.rs b/compiler/rustc_target/src/spec/avr_gnu_base.rs
index 9cc10032c71da..67a7684da2c70 100644
--- a/compiler/rustc_target/src/spec/avr_gnu_base.rs
+++ b/compiler/rustc_target/src/spec/avr_gnu_base.rs
@@ -11,7 +11,6 @@ pub fn target(target_cpu: String) -> Target {
         pointer_width: 16,
         options: TargetOptions {
             c_int_width: "16".to_string(),
-            os: "unknown".to_string(),
             cpu: target_cpu.clone(),
             exe_suffix: ".elf".to_string(),
 
diff --git a/compiler/rustc_target/src/spec/fuchsia_base.rs b/compiler/rustc_target/src/spec/fuchsia_base.rs
index e467c7c8f21e9..5c39773cbe381 100644
--- a/compiler/rustc_target/src/spec/fuchsia_base.rs
+++ b/compiler/rustc_target/src/spec/fuchsia_base.rs
@@ -21,7 +21,6 @@ pub fn opts() -> TargetOptions {
 
     TargetOptions {
         os: "fuchsia".to_string(),
-        vendor: String::new(),
         linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
         linker: Some("rust-lld".to_owned()),
         lld_flavor: LldFlavor::Ld,
diff --git a/compiler/rustc_target/src/spec/mipsel_unknown_none.rs b/compiler/rustc_target/src/spec/mipsel_unknown_none.rs
index a8005927a7beb..0f9d3c3de1543 100644
--- a/compiler/rustc_target/src/spec/mipsel_unknown_none.rs
+++ b/compiler/rustc_target/src/spec/mipsel_unknown_none.rs
@@ -14,7 +14,6 @@ pub fn target() -> Target {
         arch: "mips".to_string(),
 
         options: TargetOptions {
-            vendor: String::new(),
             linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
             cpu: "mips32r2".to_string(),
             features: "+mips32r2,+soft-float,+noabicalls".to_string(),
diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
index f949bf95a502a..b37783c5820bf 100644
--- a/compiler/rustc_target/src/spec/mod.rs
+++ b/compiler/rustc_target/src/spec/mod.rs
@@ -713,11 +713,14 @@ pub struct TargetOptions {
     pub endian: String,
     /// Width of c_int type. Defaults to "32".
     pub c_int_width: String,
-    /// OS name to use for conditional compilation. Defaults to "none".
+    /// OS name to use for conditional compilation (`target_os`). Defaults to "none".
+    /// "none" implies a bare metal target without `std` library.
+    /// A couple of targets having `std` also use "unknown" as an `os` value,
+    /// but they are exceptions.
     pub os: String,
-    /// Environment name to use for conditional compilation. Defaults to "".
+    /// Environment name to use for conditional compilation (`target_env`). Defaults to "".
     pub env: String,
-    /// Vendor name to use for conditional compilation. Defaults to "unknown".
+    /// Vendor name to use for conditional compilation (`target_vendor`). Defaults to "unknown".
     pub vendor: String,
     /// Default linker flavor used if `-C linker-flavor` or `-C linker` are not passed
     /// on the command line. Defaults to `LinkerFlavor::Gcc`.
@@ -819,10 +822,23 @@ pub struct TargetOptions {
     /// Only useful for compiling against Illumos/Solaris,
     /// as they have a different set of linker flags. Defaults to false.
     pub is_like_solaris: bool,
-    /// Whether the target toolchain is like Windows'. Only useful for compiling against Windows,
-    /// only really used for figuring out how to find libraries, since Windows uses its own
-    /// library naming convention. Defaults to false.
+    /// Whether the target is like Windows.
+    /// This is a combination of several more specific properties represented as a single flag:
+    ///   - The target uses a Windows ABI,
+    ///   - uses PE/COFF as a format for object code,
+    ///   - uses Windows-style dllexport/dllimport for shared libraries,
+    ///   - uses import libraries and .def files for symbol exports,
+    ///   - executables support setting a subsystem.
     pub is_like_windows: bool,
+    /// Whether the target is like MSVC.
+    /// This is a combination of several more specific properties represented as a single flag:
+    ///   - The target has all the properties from `is_like_windows`
+    ///     (for in-tree targets "is_like_msvc ⇒ is_like_windows" is ensured by a unit test),
+    ///   - has some MSVC-specific Windows ABI properties,
+    ///   - uses a link.exe-like linker,
+    ///   - uses CodeView/PDB for debuginfo and natvis for its visualization,
+    ///   - uses SEH-based unwinding,
+    ///   - supports control flow guard mechanism.
     pub is_like_msvc: bool,
     /// Whether the target toolchain is like Emscripten's. Only useful for compiling with
     /// Emscripten toolchain.
diff --git a/compiler/rustc_target/src/spec/msp430_none_elf.rs b/compiler/rustc_target/src/spec/msp430_none_elf.rs
index ef966cb702ec4..cc2578aa578e8 100644
--- a/compiler/rustc_target/src/spec/msp430_none_elf.rs
+++ b/compiler/rustc_target/src/spec/msp430_none_elf.rs
@@ -9,7 +9,6 @@ pub fn target() -> Target {
 
         options: TargetOptions {
             c_int_width: "16".to_string(),
-            vendor: String::new(),
             executables: true,
 
             // The LLVM backend currently can't generate object files. To
diff --git a/compiler/rustc_target/src/spec/tests/tests_impl.rs b/compiler/rustc_target/src/spec/tests/tests_impl.rs
index f348df7d5a716..9ec8467e0ac44 100644
--- a/compiler/rustc_target/src/spec/tests/tests_impl.rs
+++ b/compiler/rustc_target/src/spec/tests/tests_impl.rs
@@ -8,6 +8,7 @@ pub(super) fn test_target(target: Target) {
 
 impl Target {
     fn check_consistency(&self) {
+        assert!(self.is_like_windows || !self.is_like_msvc);
         // Check that LLD with the given flavor is treated identically to the linker it emulates.
         // If your target really needs to deviate from the rules below, except it and document the
         // reasons.
@@ -16,6 +17,7 @@ impl Target {
                 || self.linker_flavor == LinkerFlavor::Lld(LldFlavor::Link),
             self.lld_flavor == LldFlavor::Link,
         );
+        assert_eq!(self.is_like_msvc, self.lld_flavor == LldFlavor::Link);
         for args in &[
             &self.pre_link_args,
             &self.late_link_args,
@@ -36,5 +38,18 @@ impl Target {
                 && self.post_link_objects_fallback.is_empty())
                 || self.crt_objects_fallback.is_some()
         );
+        // Keep the default "unknown" vendor instead.
+        assert_ne!(self.vendor, "");
+        if !self.can_use_os_unknown() {
+            // Keep the default "none" for bare metal targets instead.
+            assert_ne!(self.os, "unknown");
+        }
+    }
+
+    // Add your target to the whitelist if it has `std` library
+    // and you certainly want "unknown" for the OS name.
+    fn can_use_os_unknown(&self) -> bool {
+        self.llvm_target == "wasm32-unknown-unknown"
+            || (self.env == "sgx" && self.vendor == "fortanix")
     }
 }
diff --git a/compiler/rustc_target/src/spec/thumb_base.rs b/compiler/rustc_target/src/spec/thumb_base.rs
index e550467502754..ec24807fec4ea 100644
--- a/compiler/rustc_target/src/spec/thumb_base.rs
+++ b/compiler/rustc_target/src/spec/thumb_base.rs
@@ -32,7 +32,6 @@ use crate::spec::{LinkerFlavor, LldFlavor, PanicStrategy, RelocModel, TargetOpti
 pub fn opts() -> TargetOptions {
     // See rust-lang/rfcs#1645 for a discussion about these defaults
     TargetOptions {
-        vendor: String::new(),
         linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
         executables: true,
         // In most cases, LLD is good enough
diff --git a/compiler/rustc_target/src/spec/uefi_msvc_base.rs b/compiler/rustc_target/src/spec/uefi_msvc_base.rs
index 79fe77495e731..322b6f530e9fd 100644
--- a/compiler/rustc_target/src/spec/uefi_msvc_base.rs
+++ b/compiler/rustc_target/src/spec/uefi_msvc_base.rs
@@ -46,15 +46,6 @@ pub fn opts() -> TargetOptions {
         stack_probes: true,
         singlethread: true,
         linker: Some("rust-lld".to_string()),
-        // FIXME: This should likely be `true` inherited from `msvc_base`
-        // because UEFI follows Windows ABI and uses PE/COFF.
-        // The `false` is probably causing ABI bugs right now.
-        is_like_windows: false,
-        // FIXME: This should likely be `true` inherited from `msvc_base`
-        // because UEFI follows Windows ABI and uses PE/COFF.
-        // The `false` is probably causing ABI bugs right now.
-        is_like_msvc: false,
-
         ..base
     }
 }
diff --git a/compiler/rustc_target/src/spec/wasm32_wasi.rs b/compiler/rustc_target/src/spec/wasm32_wasi.rs
index 9c697674f397a..3f44acdc36b2d 100644
--- a/compiler/rustc_target/src/spec/wasm32_wasi.rs
+++ b/compiler/rustc_target/src/spec/wasm32_wasi.rs
@@ -79,7 +79,6 @@ pub fn target() -> Target {
     let mut options = wasm32_base::options();
 
     options.os = "wasi".to_string();
-    options.vendor = String::new();
     options.linker_flavor = LinkerFlavor::Lld(LldFlavor::Wasm);
     options
         .pre_link_args
diff --git a/library/alloc/src/collections/btree/map.rs b/library/alloc/src/collections/btree/map.rs
index 49122f53d33ad..7151d3763f01f 100644
--- a/library/alloc/src/collections/btree/map.rs
+++ b/library/alloc/src/collections/btree/map.rs
@@ -863,6 +863,30 @@ impl<K: Ord, V> BTreeMap<K, V> {
         }
     }
 
+    /// Retains only the elements specified by the predicate.
+    ///
+    /// In other words, remove all pairs `(k, v)` such that `f(&k, &mut v)` returns `false`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(btree_retain)]
+    /// use std::collections::BTreeMap;
+    ///
+    /// let mut map: BTreeMap<i32, i32> = (0..8).map(|x| (x, x*10)).collect();
+    /// // Keep only the elements with even-numbered keys.
+    /// map.retain(|&k, _| k % 2 == 0);
+    /// assert!(map.into_iter().eq(vec![(0, 0), (2, 20), (4, 40), (6, 60)]));
+    /// ```
+    #[inline]
+    #[unstable(feature = "btree_retain", issue = "79025")]
+    pub fn retain<F>(&mut self, mut f: F)
+    where
+        F: FnMut(&K, &mut V) -> bool,
+    {
+        self.drain_filter(|k, v| !f(k, v));
+    }
+
     /// Moves all elements from `other` into `Self`, leaving `other` empty.
     ///
     /// # Examples
diff --git a/library/alloc/src/collections/btree/map/tests.rs b/library/alloc/src/collections/btree/map/tests.rs
index dd3ebcccf76a5..11dbb584abdac 100644
--- a/library/alloc/src/collections/btree/map/tests.rs
+++ b/library/alloc/src/collections/btree/map/tests.rs
@@ -808,6 +808,17 @@ fn test_range_mut() {
     map.check();
 }
 
+#[test]
+fn test_retain() {
+    let mut map: BTreeMap<i32, i32> = (0..100).map(|x| (x, x * 10)).collect();
+
+    map.retain(|&k, _| k % 2 == 0);
+    assert_eq!(map.len(), 50);
+    assert_eq!(map[&2], 20);
+    assert_eq!(map[&4], 40);
+    assert_eq!(map[&6], 60);
+}
+
 mod test_drain_filter {
     use super::*;
 
diff --git a/library/alloc/src/collections/btree/set.rs b/library/alloc/src/collections/btree/set.rs
index 684019f8f5f5e..1a807100653bc 100644
--- a/library/alloc/src/collections/btree/set.rs
+++ b/library/alloc/src/collections/btree/set.rs
@@ -798,6 +798,30 @@ impl<T: Ord> BTreeSet<T> {
         Recover::take(&mut self.map, value)
     }
 
+    /// Retains only the elements specified by the predicate.
+    ///
+    /// In other words, remove all elements `e` such that `f(&e)` returns `false`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(btree_retain)]
+    /// use std::collections::BTreeSet;
+    ///
+    /// let xs = [1, 2, 3, 4, 5, 6];
+    /// let mut set: BTreeSet<i32> = xs.iter().cloned().collect();
+    /// // Keep only the even numbers.
+    /// set.retain(|&k| k % 2 == 0);
+    /// assert!(set.iter().eq([2, 4, 6].iter()));
+    /// ```
+    #[unstable(feature = "btree_retain", issue = "79025")]
+    pub fn retain<F>(&mut self, mut f: F)
+    where
+        F: FnMut(&T) -> bool,
+    {
+        self.drain_filter(|v| !f(v));
+    }
+
     /// Moves all elements from `other` into `Self`, leaving `other` empty.
     ///
     /// # Examples
diff --git a/library/alloc/src/collections/btree/set/tests.rs b/library/alloc/src/collections/btree/set/tests.rs
index 52cde8299e418..ef40a048a382e 100644
--- a/library/alloc/src/collections/btree/set/tests.rs
+++ b/library/alloc/src/collections/btree/set/tests.rs
@@ -324,6 +324,17 @@ fn test_is_subset() {
     assert_eq!(is_subset(&[99, 100], &large), false);
 }
 
+#[test]
+fn test_retain() {
+    let xs = [1, 2, 3, 4, 5, 6];
+    let mut set: BTreeSet<i32> = xs.iter().cloned().collect();
+    set.retain(|&k| k % 2 == 0);
+    assert_eq!(set.len(), 3);
+    assert!(set.contains(&2));
+    assert!(set.contains(&4));
+    assert!(set.contains(&6));
+}
+
 #[test]
 fn test_drain_filter() {
     let mut x: BTreeSet<_> = [1].iter().copied().collect();
diff --git a/src/bootstrap/lib.rs b/src/bootstrap/lib.rs
index 9f037890483cf..ca140b9d27828 100644
--- a/src/bootstrap/lib.rs
+++ b/src/bootstrap/lib.rs
@@ -178,6 +178,7 @@ const LLVM_TOOLS: &[&str] = &[
     "llvm-size",     // used to prints the size of the linker sections of a program
     "llvm-strip",    // used to discard symbols from binary files to reduce their size
     "llvm-ar",       // used for creating and modifying archive files
+    "llvm-as",       // used to convert LLVM assembly to LLVM bitcode
     "llvm-dis",      // used to disassemble LLVM bitcode
     "llc",           // used to compile LLVM bytecode
     "opt",           // used to optimize LLVM bytecode
diff --git a/src/test/mir-opt/inline/inline-compatibility.rs b/src/test/mir-opt/inline/inline-compatibility.rs
index ff9049edb4f2c..30aff0a64efb9 100644
--- a/src/test/mir-opt/inline/inline-compatibility.rs
+++ b/src/test/mir-opt/inline/inline-compatibility.rs
@@ -1,12 +1,11 @@
 // Checks that only functions with compatible attributes are inlined.
 //
 // only-x86_64
-// needs-sanitizer-address
-// compile-flags: -Zsanitizer=address
 
 #![crate_type = "lib"]
 #![feature(no_sanitize)]
 #![feature(target_feature_11)]
+#![feature(c_variadic)]
 
 // EMIT_MIR inline_compatibility.inlined_target_feature.Inline.diff
 #[target_feature(enable = "sse2")]
@@ -35,5 +34,22 @@ pub unsafe fn not_inlined_no_sanitize() {
 pub unsafe fn target_feature() {}
 
 #[inline]
-#[no_sanitize(address, memory)]
+#[no_sanitize(address)]
 pub unsafe fn no_sanitize() {}
+
+// EMIT_MIR inline_compatibility.not_inlined_c_variadic.Inline.diff
+pub unsafe fn not_inlined_c_variadic() {
+    let s = sum(4u32, 4u32, 30u32, 200u32, 1000u32);
+}
+
+#[no_mangle]
+#[inline(always)]
+unsafe extern "C" fn sum(n: u32, mut vs: ...) -> u32 {
+    let mut s = 0;
+    let mut i = 0;
+    while i != n {
+        s += vs.arg::<u32>();
+        i += 1;
+    }
+    s
+}
diff --git a/src/test/mir-opt/inline/inline-generator.rs b/src/test/mir-opt/inline/inline-generator.rs
new file mode 100644
index 0000000000000..d11b3e548f721
--- /dev/null
+++ b/src/test/mir-opt/inline/inline-generator.rs
@@ -0,0 +1,16 @@
+// ignore-wasm32-bare compiled with panic=abort by default
+#![feature(generators, generator_trait)]
+
+use std::ops::Generator;
+use std::pin::Pin;
+
+// EMIT_MIR inline_generator.main.Inline.diff
+fn main() {
+    let _r = Pin::new(&mut g()).resume(false);
+}
+
+#[inline(always)]
+pub fn g() -> impl Generator<bool> {
+    #[inline(always)]
+    |a| { yield if a { 7 } else { 13 } }
+}
diff --git a/src/test/mir-opt/inline/inline_compatibility.inlined_no_sanitize.Inline.diff b/src/test/mir-opt/inline/inline_compatibility.inlined_no_sanitize.Inline.diff
index 451ec39422fc4..c95cf47695785 100644
--- a/src/test/mir-opt/inline/inline_compatibility.inlined_no_sanitize.Inline.diff
+++ b/src/test/mir-opt/inline/inline_compatibility.inlined_no_sanitize.Inline.diff
@@ -2,24 +2,24 @@
 + // MIR for `inlined_no_sanitize` after Inline
   
   fn inlined_no_sanitize() -> () {
-      let mut _0: ();                      // return place in scope 0 at $DIR/inline-compatibility.rs:24:37: 24:37
-      let _1: ();                          // in scope 0 at $DIR/inline-compatibility.rs:25:5: 25:18
-+     scope 1 (inlined no_sanitize) {      // at $DIR/inline-compatibility.rs:25:5: 25:18
+      let mut _0: ();                      // return place in scope 0 at $DIR/inline-compatibility.rs:23:37: 23:37
+      let _1: ();                          // in scope 0 at $DIR/inline-compatibility.rs:24:5: 24:18
++     scope 1 (inlined no_sanitize) {      // at $DIR/inline-compatibility.rs:24:5: 24:18
 +     }
   
       bb0: {
-          StorageLive(_1);                 // scope 0 at $DIR/inline-compatibility.rs:25:5: 25:18
--         _1 = no_sanitize() -> bb1;       // scope 0 at $DIR/inline-compatibility.rs:25:5: 25:18
+          StorageLive(_1);                 // scope 0 at $DIR/inline-compatibility.rs:24:5: 24:18
+-         _1 = no_sanitize() -> bb1;       // scope 0 at $DIR/inline-compatibility.rs:24:5: 24:18
 -                                          // mir::Constant
--                                          // + span: $DIR/inline-compatibility.rs:25:5: 25:16
+-                                          // + span: $DIR/inline-compatibility.rs:24:5: 24:16
 -                                          // + literal: Const { ty: unsafe fn() {no_sanitize}, val: Value(Scalar(<ZST>)) }
 -     }
 - 
 -     bb1: {
-+         _1 = const ();                   // scope 1 at $DIR/inline-compatibility.rs:25:5: 25:18
-          StorageDead(_1);                 // scope 0 at $DIR/inline-compatibility.rs:25:18: 25:19
-          _0 = const ();                   // scope 0 at $DIR/inline-compatibility.rs:24:37: 26:2
-          return;                          // scope 0 at $DIR/inline-compatibility.rs:26:2: 26:2
++         _1 = const ();                   // scope 1 at $DIR/inline-compatibility.rs:24:5: 24:18
+          StorageDead(_1);                 // scope 0 at $DIR/inline-compatibility.rs:24:18: 24:19
+          _0 = const ();                   // scope 0 at $DIR/inline-compatibility.rs:23:37: 25:2
+          return;                          // scope 0 at $DIR/inline-compatibility.rs:25:2: 25:2
       }
   }
   
diff --git a/src/test/mir-opt/inline/inline_compatibility.inlined_target_feature.Inline.diff b/src/test/mir-opt/inline/inline_compatibility.inlined_target_feature.Inline.diff
index a59ddd344cb26..2bb928343229f 100644
--- a/src/test/mir-opt/inline/inline_compatibility.inlined_target_feature.Inline.diff
+++ b/src/test/mir-opt/inline/inline_compatibility.inlined_target_feature.Inline.diff
@@ -2,24 +2,24 @@
 + // MIR for `inlined_target_feature` after Inline
   
   fn inlined_target_feature() -> () {
-      let mut _0: ();                      // return place in scope 0 at $DIR/inline-compatibility.rs:13:40: 13:40
-      let _1: ();                          // in scope 0 at $DIR/inline-compatibility.rs:14:5: 14:21
-+     scope 1 (inlined target_feature) {   // at $DIR/inline-compatibility.rs:14:5: 14:21
+      let mut _0: ();                      // return place in scope 0 at $DIR/inline-compatibility.rs:12:40: 12:40
+      let _1: ();                          // in scope 0 at $DIR/inline-compatibility.rs:13:5: 13:21
++     scope 1 (inlined target_feature) {   // at $DIR/inline-compatibility.rs:13:5: 13:21
 +     }
   
       bb0: {
-          StorageLive(_1);                 // scope 0 at $DIR/inline-compatibility.rs:14:5: 14:21
--         _1 = target_feature() -> bb1;    // scope 0 at $DIR/inline-compatibility.rs:14:5: 14:21
+          StorageLive(_1);                 // scope 0 at $DIR/inline-compatibility.rs:13:5: 13:21
+-         _1 = target_feature() -> bb1;    // scope 0 at $DIR/inline-compatibility.rs:13:5: 13:21
 -                                          // mir::Constant
--                                          // + span: $DIR/inline-compatibility.rs:14:5: 14:19
+-                                          // + span: $DIR/inline-compatibility.rs:13:5: 13:19
 -                                          // + literal: Const { ty: unsafe fn() {target_feature}, val: Value(Scalar(<ZST>)) }
 -     }
 - 
 -     bb1: {
-+         _1 = const ();                   // scope 1 at $DIR/inline-compatibility.rs:14:5: 14:21
-          StorageDead(_1);                 // scope 0 at $DIR/inline-compatibility.rs:14:21: 14:22
-          _0 = const ();                   // scope 0 at $DIR/inline-compatibility.rs:13:40: 15:2
-          return;                          // scope 0 at $DIR/inline-compatibility.rs:15:2: 15:2
++         _1 = const ();                   // scope 1 at $DIR/inline-compatibility.rs:13:5: 13:21
+          StorageDead(_1);                 // scope 0 at $DIR/inline-compatibility.rs:13:21: 13:22
+          _0 = const ();                   // scope 0 at $DIR/inline-compatibility.rs:12:40: 14:2
+          return;                          // scope 0 at $DIR/inline-compatibility.rs:14:2: 14:2
       }
   }
   
diff --git a/src/test/mir-opt/inline/inline_compatibility.not_inlined_c_variadic.Inline.diff b/src/test/mir-opt/inline/inline_compatibility.not_inlined_c_variadic.Inline.diff
new file mode 100644
index 0000000000000..09bca903c80e8
--- /dev/null
+++ b/src/test/mir-opt/inline/inline_compatibility.not_inlined_c_variadic.Inline.diff
@@ -0,0 +1,25 @@
+- // MIR for `not_inlined_c_variadic` before Inline
++ // MIR for `not_inlined_c_variadic` after Inline
+  
+  fn not_inlined_c_variadic() -> () {
+      let mut _0: ();                      // return place in scope 0 at $DIR/inline-compatibility.rs:41:40: 41:40
+      let _1: u32;                         // in scope 0 at $DIR/inline-compatibility.rs:42:9: 42:10
+      scope 1 {
+          debug s => _1;                   // in scope 1 at $DIR/inline-compatibility.rs:42:9: 42:10
+      }
+  
+      bb0: {
+          StorageLive(_1);                 // scope 0 at $DIR/inline-compatibility.rs:42:9: 42:10
+          _1 = sum(const 4_u32, const 4_u32, const 30_u32, const 200_u32, const 1000_u32) -> bb1; // scope 0 at $DIR/inline-compatibility.rs:42:13: 42:52
+                                           // mir::Constant
+                                           // + span: $DIR/inline-compatibility.rs:42:13: 42:16
+                                           // + literal: Const { ty: unsafe extern "C" fn(u32, ...) -> u32 {sum}, val: Value(Scalar(<ZST>)) }
+      }
+  
+      bb1: {
+          _0 = const ();                   // scope 0 at $DIR/inline-compatibility.rs:41:40: 43:2
+          StorageDead(_1);                 // scope 0 at $DIR/inline-compatibility.rs:43:1: 43:2
+          return;                          // scope 0 at $DIR/inline-compatibility.rs:43:2: 43:2
+      }
+  }
+  
diff --git a/src/test/mir-opt/inline/inline_compatibility.not_inlined_no_sanitize.Inline.diff b/src/test/mir-opt/inline/inline_compatibility.not_inlined_no_sanitize.Inline.diff
index 651eadc1e849c..5af3946f2e501 100644
--- a/src/test/mir-opt/inline/inline_compatibility.not_inlined_no_sanitize.Inline.diff
+++ b/src/test/mir-opt/inline/inline_compatibility.not_inlined_no_sanitize.Inline.diff
@@ -2,21 +2,21 @@
 + // MIR for `not_inlined_no_sanitize` after Inline
   
   fn not_inlined_no_sanitize() -> () {
-      let mut _0: ();                      // return place in scope 0 at $DIR/inline-compatibility.rs:29:41: 29:41
-      let _1: ();                          // in scope 0 at $DIR/inline-compatibility.rs:30:5: 30:18
+      let mut _0: ();                      // return place in scope 0 at $DIR/inline-compatibility.rs:28:41: 28:41
+      let _1: ();                          // in scope 0 at $DIR/inline-compatibility.rs:29:5: 29:18
   
       bb0: {
-          StorageLive(_1);                 // scope 0 at $DIR/inline-compatibility.rs:30:5: 30:18
-          _1 = no_sanitize() -> bb1;       // scope 0 at $DIR/inline-compatibility.rs:30:5: 30:18
+          StorageLive(_1);                 // scope 0 at $DIR/inline-compatibility.rs:29:5: 29:18
+          _1 = no_sanitize() -> bb1;       // scope 0 at $DIR/inline-compatibility.rs:29:5: 29:18
                                            // mir::Constant
-                                           // + span: $DIR/inline-compatibility.rs:30:5: 30:16
+                                           // + span: $DIR/inline-compatibility.rs:29:5: 29:16
                                            // + literal: Const { ty: unsafe fn() {no_sanitize}, val: Value(Scalar(<ZST>)) }
       }
   
       bb1: {
-          StorageDead(_1);                 // scope 0 at $DIR/inline-compatibility.rs:30:18: 30:19
-          _0 = const ();                   // scope 0 at $DIR/inline-compatibility.rs:29:41: 31:2
-          return;                          // scope 0 at $DIR/inline-compatibility.rs:31:2: 31:2
+          StorageDead(_1);                 // scope 0 at $DIR/inline-compatibility.rs:29:18: 29:19
+          _0 = const ();                   // scope 0 at $DIR/inline-compatibility.rs:28:41: 30:2
+          return;                          // scope 0 at $DIR/inline-compatibility.rs:30:2: 30:2
       }
   }
   
diff --git a/src/test/mir-opt/inline/inline_compatibility.not_inlined_target_feature.Inline.diff b/src/test/mir-opt/inline/inline_compatibility.not_inlined_target_feature.Inline.diff
index 55b9edf3adc1f..8c9fa573ce218 100644
--- a/src/test/mir-opt/inline/inline_compatibility.not_inlined_target_feature.Inline.diff
+++ b/src/test/mir-opt/inline/inline_compatibility.not_inlined_target_feature.Inline.diff
@@ -2,21 +2,21 @@
 + // MIR for `not_inlined_target_feature` after Inline
   
   fn not_inlined_target_feature() -> () {
-      let mut _0: ();                      // return place in scope 0 at $DIR/inline-compatibility.rs:18:44: 18:44
-      let _1: ();                          // in scope 0 at $DIR/inline-compatibility.rs:19:5: 19:21
+      let mut _0: ();                      // return place in scope 0 at $DIR/inline-compatibility.rs:17:44: 17:44
+      let _1: ();                          // in scope 0 at $DIR/inline-compatibility.rs:18:5: 18:21
   
       bb0: {
-          StorageLive(_1);                 // scope 0 at $DIR/inline-compatibility.rs:19:5: 19:21
-          _1 = target_feature() -> bb1;    // scope 0 at $DIR/inline-compatibility.rs:19:5: 19:21
+          StorageLive(_1);                 // scope 0 at $DIR/inline-compatibility.rs:18:5: 18:21
+          _1 = target_feature() -> bb1;    // scope 0 at $DIR/inline-compatibility.rs:18:5: 18:21
                                            // mir::Constant
-                                           // + span: $DIR/inline-compatibility.rs:19:5: 19:19
+                                           // + span: $DIR/inline-compatibility.rs:18:5: 18:19
                                            // + literal: Const { ty: unsafe fn() {target_feature}, val: Value(Scalar(<ZST>)) }
       }
   
       bb1: {
-          StorageDead(_1);                 // scope 0 at $DIR/inline-compatibility.rs:19:21: 19:22
-          _0 = const ();                   // scope 0 at $DIR/inline-compatibility.rs:18:44: 20:2
-          return;                          // scope 0 at $DIR/inline-compatibility.rs:20:2: 20:2
+          StorageDead(_1);                 // scope 0 at $DIR/inline-compatibility.rs:18:21: 18:22
+          _0 = const ();                   // scope 0 at $DIR/inline-compatibility.rs:17:44: 19:2
+          return;                          // scope 0 at $DIR/inline-compatibility.rs:19:2: 19:2
       }
   }
   
diff --git a/src/test/mir-opt/inline/inline_generator.main.Inline.diff b/src/test/mir-opt/inline/inline_generator.main.Inline.diff
new file mode 100644
index 0000000000000..aa32daa82dd51
--- /dev/null
+++ b/src/test/mir-opt/inline/inline_generator.main.Inline.diff
@@ -0,0 +1,123 @@
+- // MIR for `main` before Inline
++ // MIR for `main` after Inline
+  
+  fn main() -> () {
+      let mut _0: ();                      // return place in scope 0 at $DIR/inline-generator.rs:8:11: 8:11
+      let _1: std::ops::GeneratorState<<impl std::ops::Generator<bool> as std::ops::Generator<bool>>::Yield, <impl std::ops::Generator<bool> as std::ops::Generator<bool>>::Return>; // in scope 0 at $DIR/inline-generator.rs:9:9: 9:11
+      let mut _2: std::pin::Pin<&mut impl std::ops::Generator<bool>>; // in scope 0 at $DIR/inline-generator.rs:9:14: 9:32
+      let mut _3: &mut impl std::ops::Generator<bool>; // in scope 0 at $DIR/inline-generator.rs:9:23: 9:31
+      let mut _4: impl std::ops::Generator<bool>; // in scope 0 at $DIR/inline-generator.rs:9:28: 9:31
++     let mut _7: bool;                    // in scope 0 at $DIR/inline-generator.rs:9:14: 9:46
+      scope 1 {
+          debug _r => _1;                  // in scope 1 at $DIR/inline-generator.rs:9:9: 9:11
+      }
++     scope 2 (inlined g) {                // at $DIR/inline-generator.rs:9:28: 9:31
++     }
++     scope 3 (inlined Pin::<&mut [generator@$DIR/inline-generator.rs:15:5: 15:41 {bool, i32}]>::new) { // at $DIR/inline-generator.rs:9:14: 9:32
++         debug pointer => _3;             // in scope 3 at $DIR/inline-generator.rs:9:14: 9:32
++         let mut _5: &mut [generator@$DIR/inline-generator.rs:15:5: 15:41 {bool, i32}]; // in scope 3 at $DIR/inline-generator.rs:9:14: 9:32
++         scope 4 {
++             scope 5 (inlined Pin::<&mut [generator@$DIR/inline-generator.rs:15:5: 15:41 {bool, i32}]>::new_unchecked) { // at $DIR/inline-generator.rs:9:14: 9:32
++                 debug pointer => _5;     // in scope 5 at $DIR/inline-generator.rs:9:14: 9:32
++                 let mut _6: &mut [generator@$DIR/inline-generator.rs:15:5: 15:41 {bool, i32}]; // in scope 5 at $DIR/inline-generator.rs:9:14: 9:32
++             }
++         }
++     }
++     scope 6 (inlined g::{closure#0}) {   // at $DIR/inline-generator.rs:9:14: 9:46
++         debug a => _8;                   // in scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         let mut _8: bool;                // in scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         let mut _9: u32;                 // in scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++     }
+  
+      bb0: {
+          StorageLive(_1);                 // scope 0 at $DIR/inline-generator.rs:9:9: 9:11
+          StorageLive(_2);                 // scope 0 at $DIR/inline-generator.rs:9:14: 9:32
+          StorageLive(_3);                 // scope 0 at $DIR/inline-generator.rs:9:23: 9:31
+          StorageLive(_4);                 // scope 0 at $DIR/inline-generator.rs:9:28: 9:31
+-         _4 = g() -> bb1;                 // scope 0 at $DIR/inline-generator.rs:9:28: 9:31
+-                                          // mir::Constant
+-                                          // + span: $DIR/inline-generator.rs:9:28: 9:29
+-                                          // + literal: Const { ty: fn() -> impl std::ops::Generator<bool> {g}, val: Value(Scalar(<ZST>)) }
+-     }
+- 
+-     bb1: {
++         discriminant(_4) = 0;            // scope 2 at $DIR/inline-generator.rs:9:28: 9:31
+          _3 = &mut _4;                    // scope 0 at $DIR/inline-generator.rs:9:23: 9:31
+-         _2 = Pin::<&mut impl Generator<bool>>::new(move _3) -> [return: bb2, unwind: bb4]; // scope 0 at $DIR/inline-generator.rs:9:14: 9:32
+-                                          // mir::Constant
+-                                          // + span: $DIR/inline-generator.rs:9:14: 9:22
+-                                          // + user_ty: UserType(0)
+-                                          // + literal: Const { ty: fn(&mut impl std::ops::Generator<bool>) -> std::pin::Pin<&mut impl std::ops::Generator<bool>> {std::pin::Pin::<&mut impl std::ops::Generator<bool>>::new}, val: Value(Scalar(<ZST>)) }
+-     }
+- 
+-     bb2: {
++         StorageLive(_5);                 // scope 4 at $DIR/inline-generator.rs:9:14: 9:32
++         _5 = move _3;                    // scope 4 at $DIR/inline-generator.rs:9:14: 9:32
++         StorageLive(_6);                 // scope 5 at $DIR/inline-generator.rs:9:14: 9:32
++         _6 = move _5;                    // scope 5 at $DIR/inline-generator.rs:9:14: 9:32
++         (_2.0: &mut [generator@$DIR/inline-generator.rs:15:5: 15:41 {bool, i32}]) = move _6; // scope 5 at $DIR/inline-generator.rs:9:14: 9:32
++         StorageDead(_6);                 // scope 5 at $DIR/inline-generator.rs:9:14: 9:32
++         StorageDead(_5);                 // scope 4 at $DIR/inline-generator.rs:9:14: 9:32
+          StorageDead(_3);                 // scope 0 at $DIR/inline-generator.rs:9:31: 9:32
+-         _1 = <impl Generator<bool> as Generator<bool>>::resume(move _2, const false) -> [return: bb3, unwind: bb4]; // scope 0 at $DIR/inline-generator.rs:9:14: 9:46
+-                                          // mir::Constant
+-                                          // + span: $DIR/inline-generator.rs:9:33: 9:39
+-                                          // + literal: Const { ty: for<'r> fn(std::pin::Pin<&'r mut impl std::ops::Generator<bool>>, bool) -> std::ops::GeneratorState<<impl std::ops::Generator<bool> as std::ops::Generator<bool>>::Yield, <impl std::ops::Generator<bool> as std::ops::Generator<bool>>::Return> {<impl std::ops::Generator<bool> as std::ops::Generator<bool>>::resume}, val: Value(Scalar(<ZST>)) }
++         StorageLive(_7);                 // scope 0 at $DIR/inline-generator.rs:9:14: 9:46
++         _7 = const false;                // scope 0 at $DIR/inline-generator.rs:9:14: 9:46
++         _9 = discriminant((*(_2.0: &mut [generator@$DIR/inline-generator.rs:15:5: 15:41 {bool, i32}]))); // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         switchInt(move _9) -> [0_u32: bb3, 1_u32: bb8, 3_u32: bb7, otherwise: bb9]; // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
+      }
+  
+-     bb3: {
++     bb1: {
++         StorageDead(_7);                 // scope 0 at $DIR/inline-generator.rs:9:14: 9:46
+          StorageDead(_2);                 // scope 0 at $DIR/inline-generator.rs:9:45: 9:46
+          StorageDead(_4);                 // scope 0 at $DIR/inline-generator.rs:9:46: 9:47
+          _0 = const ();                   // scope 0 at $DIR/inline-generator.rs:8:11: 10:2
+          StorageDead(_1);                 // scope 0 at $DIR/inline-generator.rs:10:1: 10:2
+          return;                          // scope 0 at $DIR/inline-generator.rs:10:2: 10:2
+      }
+  
+-     bb4 (cleanup): {
++     bb2 (cleanup): {
+          resume;                          // scope 0 at $DIR/inline-generator.rs:8:1: 10:2
++     }
++ 
++     bb3: {
++         _8 = move _7;                    // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         switchInt(_8) -> [false: bb4, otherwise: bb5]; // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++     }
++ 
++     bb4: {
++         ((_1 as Yielded).0: i32) = const 13_i32; // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         goto -> bb6;                     // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++     }
++ 
++     bb5: {
++         ((_1 as Yielded).0: i32) = const 7_i32; // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         goto -> bb6;                     // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++     }
++ 
++     bb6: {
++         discriminant(_1) = 0;            // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         discriminant((*(_2.0: &mut [generator@$DIR/inline-generator.rs:15:5: 15:41 {bool, i32}]))) = 3; // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         goto -> bb1;                     // scope 0 at $DIR/inline-generator.rs:15:11: 15:39
++     }
++ 
++     bb7: {
++         ((_1 as Complete).0: bool) = move _7; // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         discriminant(_1) = 1;            // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         discriminant((*(_2.0: &mut [generator@$DIR/inline-generator.rs:15:5: 15:41 {bool, i32}]))) = 1; // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         goto -> bb1;                     // scope 0 at $DIR/inline-generator.rs:15:41: 15:41
++     }
++ 
++     bb8: {
++         assert(const false, "generator resumed after completion") -> [success: bb8, unwind: bb2]; // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++     }
++ 
++     bb9: {
++         unreachable;                     // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
+      }
+  }
+  
diff --git a/src/test/pretty/qpath-associated-type-bound.rs b/src/test/pretty/qpath-associated-type-bound.rs
new file mode 100644
index 0000000000000..e06885e03882b
--- /dev/null
+++ b/src/test/pretty/qpath-associated-type-bound.rs
@@ -0,0 +1,16 @@
+// pp-exact
+
+
+mod m {
+    pub trait Tr {
+        type Ts: super::Tu;
+    }
+}
+
+trait Tu {
+    fn dummy() { }
+}
+
+fn foo<T: m::Tr>() { <T as m::Tr>::Ts::dummy(); }
+
+fn main() { }
diff --git a/src/test/run-make-fulldeps/coverage-reports-base/Makefile b/src/test/run-make-fulldeps/coverage-reports-base/Makefile
index b175768e19962..1e2aa056e4008 100644
--- a/src/test/run-make-fulldeps/coverage-reports-base/Makefile
+++ b/src/test/run-make-fulldeps/coverage-reports-base/Makefile
@@ -13,15 +13,13 @@
 BASEDIR=../coverage-reports-base
 SOURCEDIR=../coverage
 
-ifeq ($(UNAME),Darwin)
-# FIXME(richkadel): It appears that --debug is not available on MacOS even when not running
-# under CI.
-NO_LLVM_ASSERTIONS=1
-endif
-
 # The `llvm-cov show` flag `--debug`, used to generate the `counters` output files, is only enabled
-# if LLVM assertions are enabled. Some CI builds disable debug assertions.
-ifndef NO_LLVM_ASSERTIONS
+# if LLVM assertions are enabled. Requires Rust config `llvm/optimize` and not
+# `llvm/release_debuginfo`. Note that some CI builds disable debug assertions (by setting
+# `NO_LLVM_ASSERTIONS=1`), so it is not OK to fail the test, but `bless`ed test results cannot be
+# generated without debug assertions.
+LLVM_COV_DEBUG := $(shell "$(LLVM_BIN_DIR)"/llvm-cov show --debug 2>&1 | grep -q "Unknown command line argument '--debug'"; echo $$?)
+ifeq ($(LLVM_COV_DEBUG), 1)
 DEBUG_FLAG=--debug
 endif
 
diff --git a/src/test/run-make-fulldeps/coverage-spanview-base/Makefile b/src/test/run-make-fulldeps/coverage-spanview-base/Makefile
index fb9f5215fe8ee..03ef04776a03b 100644
--- a/src/test/run-make-fulldeps/coverage-spanview-base/Makefile
+++ b/src/test/run-make-fulldeps/coverage-spanview-base/Makefile
@@ -9,9 +9,20 @@
 BASEDIR=../coverage-spanview-base
 SOURCEDIR=../coverage
 
-ifeq ($(UNAME),Darwin)
-SED_HAS_ISSUES=1
-endif
+define SPANVIEW_HEADER
+<!DOCTYPE html>
+<!--
+
+Preview this file as rendered HTML from the github source at:
+https://htmlpreview.github.io/?https://github.com/rust-lang/rust/blob/master/src/test/run-make-fulldeps/coverage-spanview-base/expected_mir_dump.%s/%s
+
+For revisions in Pull Requests (PR):
+  * Replace "rust-lang" with the github PR author
+  * Replace "master" with the PR branch name
+
+-->
+endef
+export SPANVIEW_HEADER
 
 all: $(patsubst $(SOURCEDIR)/%.rs,%,$(wildcard $(SOURCEDIR)/*.rs))
 
@@ -33,31 +44,12 @@ endif
 			-Zdump-mir-spanview \
 			-Zdump-mir-dir="$(TMPDIR)"/mir_dump.$@
 
-ifdef SED_HAS_ISSUES
-	# FIXME(richkadel): MacOS's default sed has some significant limitations. Until I've come up
-	# with a better workaround, I'm disabling this test for MacOS.
-	#
-	# For future reference, see if `gsed` is available as an alternative.
-	which gsed || echo "no gsed"
-else
-
 	for path in "$(TMPDIR)"/mir_dump.$@/*; do \
-		echo $$path; \
 		file="$$(basename "$$path")"; \
-		echo $$file; \
 		urlescaped="$$("$(PYTHON)" $(BASEDIR)/escape_url.py $$file)" || exit $$?; \
-		echo $$urlescaped; \
-		sed -i -e '1a\
-<!--\
-\
-Preview this file as rendered HTML from the github source at:\
-https://htmlpreview.github.io/?https://github.com/rust-lang/rust/blob/master/src/test/run-make-fulldeps/coverage-spanview-base/expected_mir_dump.$@/'"$$urlescaped"'\
-\
-For revisions in Pull Requests (PR):\
-  * Replace "rust-lang" with the github PR author\
-  * Replace "master" with the PR branch name\
-\
--->' "$$path"; \
+		printf "$$SPANVIEW_HEADER\n" "$@" "$$urlescaped" > "$$path".modified; \
+		tail -n +2 "$$path" >> "$$path".modified; \
+		mv "$$path".modified "$$path"; \
 	done && true # for/done ends in non-zero status
 
 ifdef RUSTC_BLESS_TEST
@@ -70,5 +62,3 @@ else
 	cp "$(TMPDIR)"/mir_dump.$@/*InstrumentCoverage.0.html "$(TMPDIR)"/actual_mir_dump.$@/
 	$(DIFF) -r expected_mir_dump.$@/ "$(TMPDIR)"/actual_mir_dump.$@/
 endif
-
-endif
diff --git a/src/test/rustdoc/raw-ident-eliminate-r-hashtag.rs b/src/test/rustdoc/raw-ident-eliminate-r-hashtag.rs
new file mode 100644
index 0000000000000..f895a4c2104ba
--- /dev/null
+++ b/src/test/rustdoc/raw-ident-eliminate-r-hashtag.rs
@@ -0,0 +1,22 @@
+// ignore-tidy-linelength
+
+#![crate_type="lib"]
+
+pub mod internal {
+    // @has 'raw_ident_eliminate_r_hashtag/internal/struct.mod.html'
+    pub struct r#mod;
+
+    /// See [name], [other name]
+    ///
+    /// [name]: mod
+    /// [other name]: crate::internal::mod
+    // @has 'raw_ident_eliminate_r_hashtag/internal/struct.B.html' '//*a[@href="../../raw_ident_eliminate_r_hashtag/internal/struct.mod.html"]' 'name'
+    // @has 'raw_ident_eliminate_r_hashtag/internal/struct.B.html' '//*a[@href="../../raw_ident_eliminate_r_hashtag/internal/struct.mod.html"]' 'other name'
+    pub struct B;
+}
+
+/// See [name].
+///
+/// [name]: internal::mod
+// @has 'raw_ident_eliminate_r_hashtag/struct.A.html' '//*a[@href="../raw_ident_eliminate_r_hashtag/internal/struct.mod.html"]' 'name'
+pub struct A;
diff --git a/src/test/ui/issues/issue-50865-private-impl-trait/auxiliary/lib.rs b/src/test/ui/issues/issue-50865-private-impl-trait/auxiliary/lib.rs
index fb4bf2b8b44e7..f3a51b415faca 100644
--- a/src/test/ui/issues/issue-50865-private-impl-trait/auxiliary/lib.rs
+++ b/src/test/ui/issues/issue-50865-private-impl-trait/auxiliary/lib.rs
@@ -1,7 +1,3 @@
-// revisions: default miropt
-//[miropt]compile-flags: -Z mir-opt-level=2
-// ~^ This flag is for #77668, it used to be ICE.
-
 #![crate_type = "lib"]
 
 pub fn bar<P>( // Error won't happen if "bar" is not generic
diff --git a/src/test/ui/mir/mir-inlining/ice-issue-77306-1.rs b/src/test/ui/mir/mir-inlining/ice-issue-77306-1.rs
index 4d083bf232155..ccb279f7fa212 100644
--- a/src/test/ui/mir/mir-inlining/ice-issue-77306-1.rs
+++ b/src/test/ui/mir/mir-inlining/ice-issue-77306-1.rs
@@ -1,17 +1,27 @@
-// run-pass
+// Regression test for various issues related to normalization & inlining.
+// * #68347, #77306, #77668 - missed normalization during inlining.
+// * #78442 - missed normalization in validator after inlining.
+//
+// build-pass
 // compile-flags:-Zmir-opt-level=2
 
-// Previously ICEd because we did not normalize during inlining,
-// see https://github.com/rust-lang/rust/pull/77306 for more discussion.
-
 pub fn write() {
     create()()
 }
 
+pub fn write_generic<T>(_t: T) {
+    hide()();
+}
+
 pub fn create() -> impl FnOnce() {
    || ()
 }
 
+pub fn hide() -> impl Fn() {
+    write
+}
+
 fn main() {
     write();
+    write_generic(());
 }