Auto merge of #120283 - fmease:rollup-rk0f6r5, r=fmease

Rollup of 9 pull requests

Successful merges:

 - #112806 (Small code improvements in `collect_intra_doc_links.rs`)
 - #119766 (Split tait and impl trait in assoc items logic)
 - #120139 (Do not normalize closure signature when building `FnOnce` shim)
 - #120160 (Manually implement derived `NonZero` traits.)
 - #120171 (Fix assume and assert in jump threading)
 - #120183 (Add `#[coverage(off)]` to closures introduced by `#[test]` and `#[bench]`)
 - #120195 (add several resolution test cases)
 - #120259 (Split Diagnostics for Uncommon Codepoints: Add List to Display Characters Involved)
 - #120261 (Provide structured suggestion to use trait objects in some cases of `if` arm type divergence)

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_builtin_macros/src/lib.rs

@@ -6,6 +6,7 @@
 #![doc(rust_logo)]
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(array_windows)]
+#![feature(assert_matches)]
 #![feature(box_patterns)]
 #![feature(decl_macro)]
 #![feature(if_let_guard)]

compiler/rustc_builtin_macros/src/test.rs

@@ -9,6 +9,7 @@ use rustc_errors::{Applicability, DiagnosticBuilder, Level};
 use rustc_expand::base::*;
 use rustc_span::symbol::{sym, Ident, Symbol};
 use rustc_span::{ErrorGuaranteed, FileNameDisplayPreference, Span};
+use std::assert_matches::assert_matches;
 use std::iter;
 use thin_vec::{thin_vec, ThinVec};
 
@@ -182,6 +183,16 @@ pub fn expand_test_or_bench(
     // creates $name: $expr
     let field = |name, expr| cx.field_imm(sp, Ident::from_str_and_span(name, sp), expr);
 
+    // Adds `#[coverage(off)]` to a closure, so it won't be instrumented in
+    // `-Cinstrument-coverage` builds.
+    // This requires `#[allow_internal_unstable(coverage_attribute)]` on the
+    // corresponding macro declaration in `core::macros`.
+    let coverage_off = |mut expr: P<ast::Expr>| {
+        assert_matches!(expr.kind, ast::ExprKind::Closure(_));
+        expr.attrs.push(cx.attr_nested_word(sym::coverage, sym::off, sp));
+        expr
+    };
+
     let test_fn = if is_bench {
         // A simple ident for a lambda
         let b = Ident::from_str_and_span("b", attr_sp);
@@ -190,8 +201,9 @@ pub fn expand_test_or_bench(
             sp,
             cx.expr_path(test_path("StaticBenchFn")),
             thin_vec![
+                // #[coverage(off)]
                 // |b| self::test::assert_test_result(
-                cx.lambda1(
+                coverage_off(cx.lambda1(
                     sp,
                     cx.expr_call(
                         sp,
@@ -206,16 +218,17 @@ pub fn expand_test_or_bench(
                         ],
                     ),
                     b,
-                ), // )
+                )), // )
             ],
         )
     } else {
         cx.expr_call(
             sp,
             cx.expr_path(test_path("StaticTestFn")),
             thin_vec![
+                // #[coverage(off)]
                 // || {
-                cx.lambda0(
+                coverage_off(cx.lambda0(
                     sp,
                     // test::assert_test_result(
                     cx.expr_call(
@@ -230,7 +243,7 @@ pub fn expand_test_or_bench(
                             ), // )
                         ],
                     ), // }
-                ), // )
+                )), // )
             ],
         )
     };

compiler/rustc_codegen_cranelift/src/base.rs

@@ -682,7 +682,6 @@ fn codegen_stmt<'tcx>(
                                 args,
                                 ty::ClosureKind::FnOnce,
                             )
-                            .expect("failed to normalize and resolve closure during codegen")
                             .polymorphize(fx.tcx);
                             let func_ref = fx.get_function_ref(instance);
                             let func_addr = fx.bcx.ins().func_addr(fx.pointer_type, func_ref);

compiler/rustc_codegen_ssa/src/mir/rvalue.rs

@@ -435,7 +435,6 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                                     args,
                                     ty::ClosureKind::FnOnce,
                                 )
-                                .expect("failed to normalize and resolve closure during codegen")
                                 .polymorphize(bx.cx().tcx());
                                 OperandValue::Immediate(bx.cx().get_fn_addr(instance))
                             }

compiler/rustc_const_eval/src/interpret/cast.rs

@@ -117,8 +117,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                             def_id,
                             args,
                             ty::ClosureKind::FnOnce,
-                        )
-                        .ok_or_else(|| err_inval!(TooGeneric))?;
+                        );
                         let fn_ptr = self.fn_ptr(FnVal::Instance(instance));
                         self.write_pointer(fn_ptr, dest)?;
                     }

compiler/rustc_errors/src/diagnostic_impls.rs

@@ -110,6 +110,14 @@ impl IntoDiagnosticArg for char {
     }
 }
 
+impl IntoDiagnosticArg for Vec<char> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::StrListSepByAnd(
+            self.into_iter().map(|c| Cow::Owned(format!("{c:?}"))).collect(),
+        )
+    }
+}
+
 impl IntoDiagnosticArg for Symbol {
     fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
         self.to_ident_string().into_diagnostic_arg()

compiler/rustc_hir_analysis/src/collect/type_of.rs

@@ -530,9 +530,13 @@ pub(super) fn type_of_opaque(
         Ok(ty::EarlyBinder::bind(match tcx.hir_node_by_def_id(def_id) {
             Node::Item(item) => match item.kind {
                 ItemKind::OpaqueTy(OpaqueTy {
-                    origin: hir::OpaqueTyOrigin::TyAlias { .. },
+                    origin: hir::OpaqueTyOrigin::TyAlias { in_assoc_ty: false },
                     ..
                 }) => opaque::find_opaque_ty_constraints_for_tait(tcx, def_id),
+                ItemKind::OpaqueTy(OpaqueTy {
+                    origin: hir::OpaqueTyOrigin::TyAlias { in_assoc_ty: true },
+                    ..
+                }) => opaque::find_opaque_ty_constraints_for_impl_trait_in_assoc_type(tcx, def_id),
                 // Opaque types desugared from `impl Trait`.
                 ItemKind::OpaqueTy(&OpaqueTy {
                     origin:

compiler/rustc_hir_analysis/src/collect/type_of/opaque.rs

@@ -23,6 +23,60 @@ pub fn test_opaque_hidden_types(tcx: TyCtxt<'_>) -> Result<(), ErrorGuaranteed>
     res
 }
 
+/// Checks "defining uses" of opaque `impl Trait` in associated types.
+/// These can only be defined by associated items of the same trait.
+#[instrument(skip(tcx), level = "debug")]
+pub(super) fn find_opaque_ty_constraints_for_impl_trait_in_assoc_type(
+    tcx: TyCtxt<'_>,
+    def_id: LocalDefId,
+) -> Ty<'_> {
+    let mut parent_def_id = def_id;
+    while tcx.def_kind(parent_def_id) == def::DefKind::OpaqueTy {
+        // Account for `type Alias = impl Trait<Foo = impl Trait>;` (#116031)
+        parent_def_id = tcx.local_parent(parent_def_id);
+    }
+    let impl_def_id = tcx.local_parent(parent_def_id);
+    match tcx.def_kind(impl_def_id) {
+        DefKind::Impl { .. } => {}
+        other => bug!("invalid impl trait in assoc type parent: {other:?}"),
+    }
+
+    let mut locator = TaitConstraintLocator { def_id, tcx, found: None, typeck_types: vec![] };
+
+    for &assoc_id in tcx.associated_item_def_ids(impl_def_id) {
+        let assoc = tcx.associated_item(assoc_id);
+        match assoc.kind {
+            ty::AssocKind::Const | ty::AssocKind::Fn => {
+                locator.check(assoc_id.expect_local(), ImplTraitSource::AssocTy)
+            }
+            // Associated types don't have bodies, so they can't constrain hidden types
+            ty::AssocKind::Type => {}
+        }
+    }
+
+    if let Some(hidden) = locator.found {
+        // Only check against typeck if we didn't already error
+        if !hidden.ty.references_error() {
+            for concrete_type in locator.typeck_types {
+                if concrete_type.ty != tcx.erase_regions(hidden.ty)
+                    && !(concrete_type, hidden).references_error()
+                {
+                    hidden.report_mismatch(&concrete_type, def_id, tcx).emit();
+                }
+            }
+        }
+
+        hidden.ty
+    } else {
+        let reported = tcx.dcx().emit_err(UnconstrainedOpaqueType {
+            span: tcx.def_span(def_id),
+            name: tcx.item_name(parent_def_id.to_def_id()),
+            what: "impl",
+        });
+        Ty::new_error(tcx, reported)
+    }
+}
+
 /// Checks "defining uses" of opaque `impl Trait` types to ensure that they meet the restrictions
 /// laid for "higher-order pattern unification".
 /// This ensures that inference is tractable.
@@ -128,9 +182,15 @@ struct TaitConstraintLocator<'tcx> {
     typeck_types: Vec<ty::OpaqueHiddenType<'tcx>>,
 }
 
+#[derive(Debug)]
+enum ImplTraitSource {
+    AssocTy,
+    TyAlias,
+}
+
 impl TaitConstraintLocator<'_> {
     #[instrument(skip(self), level = "debug")]
-    fn check(&mut self, item_def_id: LocalDefId) {
+    fn check(&mut self, item_def_id: LocalDefId, source: ImplTraitSource) {
         // Don't try to check items that cannot possibly constrain the type.
         if !self.tcx.has_typeck_results(item_def_id) {
             debug!("no constraint: no typeck results");
@@ -182,7 +242,13 @@ impl TaitConstraintLocator<'_> {
                 continue;
             }
             constrained = true;
-            if !self.tcx.opaque_types_defined_by(item_def_id).contains(&self.def_id) {
+            let opaque_types_defined_by = match source {
+                ImplTraitSource::AssocTy => {
+                    self.tcx.impl_trait_in_assoc_types_defined_by(item_def_id)
+                }
+                ImplTraitSource::TyAlias => self.tcx.opaque_types_defined_by(item_def_id),
+            };
+            if !opaque_types_defined_by.contains(&self.def_id) {
                 self.tcx.dcx().emit_err(TaitForwardCompat {
                     span: hidden_type.span,
                     item_span: self
@@ -240,29 +306,29 @@ impl<'tcx> intravisit::Visitor<'tcx> for TaitConstraintLocator<'tcx> {
     }
     fn visit_expr(&mut self, ex: &'tcx Expr<'tcx>) {
         if let hir::ExprKind::Closure(closure) = ex.kind {
-            self.check(closure.def_id);
+            self.check(closure.def_id, ImplTraitSource::TyAlias);
         }
         intravisit::walk_expr(self, ex);
     }
     fn visit_item(&mut self, it: &'tcx Item<'tcx>) {
         trace!(?it.owner_id);
         // The opaque type itself or its children are not within its reveal scope.
         if it.owner_id.def_id != self.def_id {
-            self.check(it.owner_id.def_id);
+            self.check(it.owner_id.def_id, ImplTraitSource::TyAlias);
             intravisit::walk_item(self, it);
         }
     }
     fn visit_impl_item(&mut self, it: &'tcx ImplItem<'tcx>) {
         trace!(?it.owner_id);
         // The opaque type itself or its children are not within its reveal scope.
         if it.owner_id.def_id != self.def_id {
-            self.check(it.owner_id.def_id);
+            self.check(it.owner_id.def_id, ImplTraitSource::TyAlias);
             intravisit::walk_impl_item(self, it);
         }
     }
     fn visit_trait_item(&mut self, it: &'tcx TraitItem<'tcx>) {
         trace!(?it.owner_id);
-        self.check(it.owner_id.def_id);
+        self.check(it.owner_id.def_id, ImplTraitSource::TyAlias);
         intravisit::walk_trait_item(self, it);
     }
     fn visit_foreign_item(&mut self, it: &'tcx hir::ForeignItem<'tcx>) {

compiler/rustc_hir_typeck/src/demand.rs

@@ -44,7 +44,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             || self.suggest_non_zero_new_unwrap(err, expr, expected, expr_ty)
             || self.suggest_calling_boxed_future_when_appropriate(err, expr, expected, expr_ty)
             || self.suggest_no_capture_closure(err, expected, expr_ty)
-            || self.suggest_boxing_when_appropriate(err, expr.span, expr.hir_id, expected, expr_ty)
+            || self.suggest_boxing_when_appropriate(
+                err,
+                expr.peel_blocks().span,
+                expr.hir_id,
+                expected,
+                expr_ty,
+            )
             || self.suggest_block_to_brackets_peeling_refs(err, expr, expr_ty, expected)
             || self.suggest_copied_cloned_or_as_ref(err, expr, expr_ty, expected)
             || self.suggest_clone_for_ref(err, expr, expr_ty, expected)