rust-lang · Dylan-DPC · Jul 6, 2022 · Jul 2, 2022 · Jul 8, 2022 · Jul 8, 2022
diff --git a/compiler/rustc_middle/src/mir/visit.rs b/compiler/rustc_middle/src/mir/visit.rs
@@ -1111,11 +1111,9 @@ macro_rules! visit_place_fns {
             context: PlaceContext,
             location: Location,
         ) {
-            // FIXME: Use PlaceRef::iter_projections, once that exists.
-            let mut cursor = place_ref.projection;
-            while let &[ref proj_base @ .., elem] = cursor {
-                cursor = proj_base;
-                self.visit_projection_elem(place_ref.local, cursor, elem, context, location);
+            for (base, elem) in place_ref.iter_projections().rev() {
+                let base_proj = base.projection;
+                self.visit_projection_elem(place_ref.local, base_proj, elem, context, location);
             }
         }
 

diff --git a/compiler/rustc_middle/src/ty/generics.rs b/compiler/rustc_middle/src/ty/generics.rs
@@ -85,10 +85,10 @@ impl GenericParamDef {
     ) -> Option<EarlyBinder<ty::GenericArg<'tcx>>> {
         match self.kind {
             GenericParamDefKind::Type { has_default, .. } if has_default => {
-                Some(EarlyBinder(tcx.type_of(self.def_id).into()))
+                Some(tcx.bound_type_of(self.def_id).map_bound(|t| t.into()))
             }
             GenericParamDefKind::Const { has_default } if has_default => {
-                Some(EarlyBinder(tcx.const_param_default(self.def_id).into()))
+                Some(tcx.bound_const_param_default(self.def_id).map_bound(|c| c.into()))
             }
             _ => None,
         }

diff --git a/compiler/rustc_middle/src/ty/sty.rs b/compiler/rustc_middle/src/ty/sty.rs
@@ -932,6 +932,10 @@ impl<T> EarlyBinder<T> {
         let value = f(self.0)?;
         Ok(EarlyBinder(value))
     }
+
+    pub fn rebind<U>(&self, value: U) -> EarlyBinder<U> {
+        EarlyBinder(value)
+    }
 }
 
 impl<T> EarlyBinder<Option<T>> {

diff --git a/compiler/rustc_middle/src/ty/util.rs b/compiler/rustc_middle/src/ty/util.rs
@@ -676,6 +676,10 @@ impl<'tcx> TyCtxt<'tcx> {
     ) -> ty::EarlyBinder<&'tcx ty::List<ty::Predicate<'tcx>>> {
         ty::EarlyBinder(self.item_bounds(def_id))
     }
+
+    pub fn bound_const_param_default(self, def_id: DefId) -> ty::EarlyBinder<ty::Const<'tcx>> {
+        ty::EarlyBinder(self.const_param_default(def_id))
+    }
 }
 
 struct OpaqueTypeExpander<'tcx> {

diff --git a/compiler/rustc_mir_transform/src/shim.rs b/compiler/rustc_mir_transform/src/shim.rs
@@ -537,13 +537,12 @@ fn build_call_shim<'tcx>(
     };
 
     let def_id = instance.def_id();
-    let sig = tcx.fn_sig(def_id);
-    let mut sig = tcx.erase_late_bound_regions(sig);
+    let sig = tcx.bound_fn_sig(def_id);
+    let sig = sig.map_bound(|sig| tcx.erase_late_bound_regions(sig));
 
     assert_eq!(sig_substs.is_some(), !instance.has_polymorphic_mir_body());
-    if let Some(sig_substs) = sig_substs {
-        sig = EarlyBinder(sig).subst(tcx, sig_substs);
-    }
+    let mut sig =
+        if let Some(sig_substs) = sig_substs { sig.subst(tcx, sig_substs) } else { sig.0 };
 
     if let CallKind::Indirect(fnty) = call_kind {
         // `sig` determines our local decls, and thus the callee type in the `Call` terminator. This

diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
@@ -1393,7 +1393,9 @@ impl<'a> Parser<'a> {
             self.parse_yield_expr(attrs)
         } else if self.is_do_yeet() {
             self.parse_yeet_expr(attrs)
-        } else if self.eat_keyword(kw::Let) {
+        } else if self.check_keyword(kw::Let) {
+            self.manage_let_chains_context();
+            self.bump();
             self.parse_let_expr(attrs)
         } else if self.eat_keyword(kw::Underscore) {
             Ok(self.mk_expr(self.prev_token.span, ExprKind::Underscore, attrs))
@@ -2355,16 +2357,30 @@ impl<'a> Parser<'a> {
         Ok(cond)
     }
 
+    // Checks if `let` is in an invalid position like `let x = let y = 1;` or
+    // if the current `let` is in a let_chains context but nested in another
+    // expression like `if let Some(_) = _opt && [1, 2, 3][let _ = ()] = 1`.
+    //
+    // This method expects that the current token is `let`.
+    fn manage_let_chains_context(&mut self) {
+        debug_assert!(matches!(self.token.kind, TokenKind::Ident(kw::Let, _)));
+        let is_in_a_let_chains_context_but_nested_in_other_expr = self.let_expr_allowed
+            && !matches!(
+                self.prev_token.kind,
+                TokenKind::AndAnd
+                    | TokenKind::CloseDelim(Delimiter::Brace)
+                    | TokenKind::Ident(kw::If, _)
+                    | TokenKind::Ident(kw::While, _)
+            );
+        if !self.let_expr_allowed || is_in_a_let_chains_context_but_nested_in_other_expr {
+            self.struct_span_err(self.token.span, "expected expression, found `let` statement")
+                .emit();
+        }
+    }
+
     /// Parses a `let $pat = $expr` pseudo-expression.
     /// The `let` token has already been eaten.
     fn parse_let_expr(&mut self, attrs: AttrVec) -> PResult<'a, P<Expr>> {
-        if !self.let_expr_allowed {
-            self.struct_span_err(
-                self.prev_token.span,
-                "expected expression, found `let` statement",
-            )
-            .emit();
-        }
         let lo = self.prev_token.span;
         let pat = self.parse_pat_allow_top_alt(
             None,

diff --git a/compiler/rustc_target/src/spec/aarch64_unknown_none.rs b/compiler/rustc_target/src/spec/aarch64_unknown_none.rs
@@ -13,7 +13,6 @@ pub fn target() -> Target {
         linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
         linker: Some("rust-lld".into()),
         features: "+strict-align,+neon,+fp-armv8".into(),
-        executables: true,
         relocation_model: RelocModel::Static,
         disable_redzone: true,
         max_atomic_width: Some(128),

diff --git a/compiler/rustc_target/src/spec/aarch64_unknown_none_softfloat.rs b/compiler/rustc_target/src/spec/aarch64_unknown_none_softfloat.rs
@@ -14,7 +14,6 @@ pub fn target() -> Target {
         linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
         linker: Some("rust-lld".into()),
         features: "+strict-align,-neon,-fp-armv8".into(),
-        executables: true,
         relocation_model: RelocModel::Static,
         disable_redzone: true,
         max_atomic_width: Some(128),

diff --git a/compiler/rustc_target/src/spec/apple_base.rs b/compiler/rustc_target/src/spec/apple_base.rs
@@ -25,7 +25,6 @@ pub fn opts(os: &'static str) -> TargetOptions {
         function_sections: false,
         dynamic_linking: true,
         linker_is_gnu: false,
-        executables: true,
         families: cvs!["unix"],
         is_like_osx: true,
         default_dwarf_version: 2,

diff --git a/compiler/rustc_target/src/spec/apple_sdk_base.rs b/compiler/rustc_target/src/spec/apple_sdk_base.rs
@@ -54,7 +54,6 @@ pub fn opts(os: &'static str, arch: Arch) -> TargetOptions {
         abi: target_abi(arch).into(),
         cpu: target_cpu(arch).into(),
         dynamic_linking: false,
-        executables: true,
         link_env_remove: link_env_remove(arch),
         has_thread_local: false,
         ..super::apple_base::opts(os)

diff --git a/compiler/rustc_target/src/spec/armebv7r_none_eabi.rs b/compiler/rustc_target/src/spec/armebv7r_none_eabi.rs
@@ -14,7 +14,6 @@ pub fn target() -> Target {
             abi: "eabi".into(),
             endian: Endian::Big,
             linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
-            executables: true,
             linker: Some("rust-lld".into()),
             relocation_model: RelocModel::Static,
             panic_strategy: PanicStrategy::Abort,

diff --git a/compiler/rustc_target/src/spec/armebv7r_none_eabihf.rs b/compiler/rustc_target/src/spec/armebv7r_none_eabihf.rs
@@ -14,7 +14,6 @@ pub fn target() -> Target {
             abi: "eabihf".into(),
             endian: Endian::Big,
             linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
-            executables: true,
             linker: Some("rust-lld".into()),
             relocation_model: RelocModel::Static,
             panic_strategy: PanicStrategy::Abort,

diff --git a/compiler/rustc_target/src/spec/armv6k_nintendo_3ds.rs b/compiler/rustc_target/src/spec/armv6k_nintendo_3ds.rs
@@ -23,7 +23,6 @@ pub fn target() -> Target {
             abi: "eabihf".into(),
             linker_flavor: LinkerFlavor::Gcc,
             cpu: "mpcore".into(),
-            executables: true,
             families: cvs!["unix"],
             linker: Some("arm-none-eabi-gcc".into()),
             relocation_model: RelocModel::Static,

diff --git a/compiler/rustc_target/src/spec/armv7a_none_eabi.rs b/compiler/rustc_target/src/spec/armv7a_none_eabi.rs
@@ -22,7 +22,6 @@ pub fn target() -> Target {
         linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
         linker: Some("rust-lld".into()),
         features: "+v7,+thumb2,+soft-float,-neon,+strict-align".into(),
-        executables: true,
         relocation_model: RelocModel::Static,
         disable_redzone: true,
         max_atomic_width: Some(64),

diff --git a/compiler/rustc_target/src/spec/armv7a_none_eabihf.rs b/compiler/rustc_target/src/spec/armv7a_none_eabihf.rs
@@ -13,7 +13,6 @@ pub fn target() -> Target {
         linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
         linker: Some("rust-lld".into()),
         features: "+v7,+vfp3,-d32,+thumb2,-neon,+strict-align".into(),
-        executables: true,
         relocation_model: RelocModel::Static,
         disable_redzone: true,
         max_atomic_width: Some(64),

diff --git a/compiler/rustc_target/src/spec/armv7r_none_eabi.rs b/compiler/rustc_target/src/spec/armv7r_none_eabi.rs
@@ -13,7 +13,6 @@ pub fn target() -> Target {
         options: TargetOptions {
             abi: "eabi".into(),
             linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
-            executables: true,
             linker: Some("rust-lld".into()),
             relocation_model: RelocModel::Static,
             panic_strategy: PanicStrategy::Abort,

diff --git a/compiler/rustc_target/src/spec/armv7r_none_eabihf.rs b/compiler/rustc_target/src/spec/armv7r_none_eabihf.rs
@@ -13,7 +13,6 @@ pub fn target() -> Target {
         options: TargetOptions {
             abi: "eabihf".into(),
             linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
-            executables: true,
             linker: Some("rust-lld".into()),
             relocation_model: RelocModel::Static,
             panic_strategy: PanicStrategy::Abort,

diff --git a/compiler/rustc_target/src/spec/avr_gnu_base.rs b/compiler/rustc_target/src/spec/avr_gnu_base.rs
@@ -16,7 +16,6 @@ pub fn target(target_cpu: &'static str, mmcu: &'static str) -> Target {
             exe_suffix: ".elf".into(),
 
             linker: Some("avr-gcc".into()),
-            executables: true,
             eh_frame_header: false,
             pre_link_args: TargetOptions::link_args(LinkerFlavor::Gcc, &[mmcu]),
             late_link_args: TargetOptions::link_args(LinkerFlavor::Gcc, &["-lgcc"]),

diff --git a/compiler/rustc_target/src/spec/bpf_base.rs b/compiler/rustc_target/src/spec/bpf_base.rs
@@ -7,7 +7,6 @@ pub fn opts(endian: Endian) -> TargetOptions {
         endian,
         linker_flavor: LinkerFlavor::BpfLinker,
         atomic_cas: false,
-        executables: true,
         dynamic_linking: true,
         no_builtins: true,
         panic_strategy: PanicStrategy::Abort,

diff --git a/compiler/rustc_target/src/spec/dragonfly_base.rs b/compiler/rustc_target/src/spec/dragonfly_base.rs
@@ -4,7 +4,6 @@ pub fn opts() -> TargetOptions {
     TargetOptions {
         os: "dragonfly".into(),
         dynamic_linking: true,
-        executables: true,
         families: cvs!["unix"],
         has_rpath: true,
         position_independent_executables: true,

diff --git a/compiler/rustc_target/src/spec/freebsd_base.rs b/compiler/rustc_target/src/spec/freebsd_base.rs
@@ -4,7 +4,6 @@ pub fn opts() -> TargetOptions {
     TargetOptions {
         os: "freebsd".into(),
         dynamic_linking: true,
-        executables: true,
         families: cvs!["unix"],
         has_rpath: true,
         position_independent_executables: true,

diff --git a/compiler/rustc_target/src/spec/fuchsia_base.rs b/compiler/rustc_target/src/spec/fuchsia_base.rs
@@ -23,7 +23,6 @@ pub fn opts() -> TargetOptions {
         linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
         linker: Some("rust-lld".into()),
         dynamic_linking: true,
-        executables: true,
         families: cvs!["unix"],
         pre_link_args,
         pre_link_objects: crt_objects::new(&[

diff --git a/compiler/rustc_target/src/spec/haiku_base.rs b/compiler/rustc_target/src/spec/haiku_base.rs
@@ -4,7 +4,6 @@ pub fn opts() -> TargetOptions {
     TargetOptions {
         os: "haiku".into(),
         dynamic_linking: true,
-        executables: true,
         families: cvs!["unix"],
         relro_level: RelroLevel::Full,
         ..Default::default()

diff --git a/compiler/rustc_target/src/spec/hermit_base.rs b/compiler/rustc_target/src/spec/hermit_base.rs
@@ -10,7 +10,6 @@ pub fn opts() -> TargetOptions {
         os: "hermit".into(),
         linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
         linker: Some("rust-lld".into()),
-        executables: true,
         has_thread_local: true,
         pre_link_args,
         panic_strategy: PanicStrategy::Abort,

diff --git a/compiler/rustc_target/src/spec/hexagon_unknown_linux_musl.rs b/compiler/rustc_target/src/spec/hexagon_unknown_linux_musl.rs
@@ -11,7 +11,6 @@ pub fn target() -> Target {
     base.has_rpath = true;
     base.linker_is_gnu = false;
     base.dynamic_linking = true;
-    base.executables = true;
 
     base.c_enum_min_bits = 8;
 

diff --git a/compiler/rustc_target/src/spec/illumos_base.rs b/compiler/rustc_target/src/spec/illumos_base.rs
@@ -27,7 +27,6 @@ pub fn opts() -> TargetOptions {
     TargetOptions {
         os: "illumos".into(),
         dynamic_linking: true,
-        executables: true,
         has_rpath: true,
         families: cvs!["unix"],
         is_like_solaris: true,

diff --git a/compiler/rustc_target/src/spec/l4re_base.rs b/compiler/rustc_target/src/spec/l4re_base.rs
@@ -5,7 +5,6 @@ pub fn opts() -> TargetOptions {
         os: "l4re".into(),
         env: "uclibc".into(),
         linker_flavor: LinkerFlavor::L4Bender,
-        executables: true,
         panic_strategy: PanicStrategy::Abort,
         linker: Some("l4-bender".into()),
         linker_is_gnu: false,

diff --git a/compiler/rustc_target/src/spec/linux_base.rs b/compiler/rustc_target/src/spec/linux_base.rs
@@ -4,7 +4,6 @@ pub fn opts() -> TargetOptions {
     TargetOptions {
         os: "linux".into(),
         dynamic_linking: true,
-        executables: true,
         families: cvs!["unix"],
         has_rpath: true,
         position_independent_executables: true,

diff --git a/compiler/rustc_target/src/spec/mipsel_sony_psp.rs b/compiler/rustc_target/src/spec/mipsel_sony_psp.rs
@@ -18,7 +18,6 @@ pub fn target() -> Target {
             vendor: "sony".into(),
             linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
             cpu: "mips2".into(),
-            executables: true,
             linker: Some("rust-lld".into()),
             relocation_model: RelocModel::Static,
 

diff --git a/compiler/rustc_target/src/spec/mipsel_unknown_none.rs b/compiler/rustc_target/src/spec/mipsel_unknown_none.rs
@@ -17,7 +17,6 @@ pub fn target() -> Target {
             cpu: "mips32r2".into(),
             features: "+mips32r2,+soft-float,+noabicalls".into(),
             max_atomic_width: Some(32),
-            executables: true,
             linker: Some("rust-lld".into()),
             panic_strategy: PanicStrategy::Abort,
             relocation_model: RelocModel::Static,

diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
@@ -1212,8 +1212,7 @@ pub struct TargetOptions {
     pub dynamic_linking: bool,
     /// If dynamic linking is available, whether only cdylibs are supported.
     pub only_cdylib: bool,
-    /// Whether executables are available on this target. iOS, for example, only allows static
-    /// libraries. Defaults to false.
+    /// Whether executables are available on this target. Defaults to true.
     pub executables: bool,
     /// Relocation model to use in object file. Corresponds to `llc
     /// -relocation-model=$relocation_model`. Defaults to `Pic`.
@@ -1520,7 +1519,7 @@ impl Default for TargetOptions {
             features: "".into(),
             dynamic_linking: false,
             only_cdylib: false,
-            executables: false,
+            executables: true,
             relocation_model: RelocModel::Pic,
             code_model: None,
             tls_model: TlsModel::GeneralDynamic,

diff --git 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".into(),
-            executables: true,
 
             // The LLVM backend currently can't generate object files. To
             // workaround this LLVM generates assembly files which then we feed

diff --git a/compiler/rustc_target/src/spec/msvc_base.rs b/compiler/rustc_target/src/spec/msvc_base.rs
@@ -7,7 +7,6 @@ pub fn opts() -> TargetOptions {
 
     TargetOptions {
         linker_flavor: LinkerFlavor::Msvc,
-        executables: true,
         is_like_windows: true,
         is_like_msvc: true,
         lld_flavor: LldFlavor::Link,

diff --git a/compiler/rustc_target/src/spec/netbsd_base.rs b/compiler/rustc_target/src/spec/netbsd_base.rs
@@ -4,7 +4,6 @@ pub fn opts() -> TargetOptions {
     TargetOptions {
         os: "netbsd".into(),
         dynamic_linking: true,
-        executables: true,
         families: cvs!["unix"],
         no_default_libraries: false,
         has_rpath: true,

diff --git a/compiler/rustc_target/src/spec/nvptx64_nvidia_cuda.rs b/compiler/rustc_target/src/spec/nvptx64_nvidia_cuda.rs
@@ -26,7 +26,6 @@ pub fn target() -> Target {
 
             // Needed to use `dylib` and `bin` crate types and the linker.
             dynamic_linking: true,
-            executables: true,
 
             // Avoid using dylib because it contain metadata not supported
             // by LLVM NVPTX backend.

diff --git a/compiler/rustc_target/src/spec/openbsd_base.rs b/compiler/rustc_target/src/spec/openbsd_base.rs
@@ -4,7 +4,6 @@ pub fn opts() -> TargetOptions {
     TargetOptions {
         os: "openbsd".into(),
         dynamic_linking: true,
-        executables: true,
         families: cvs!["unix"],
         has_rpath: true,
         abi_return_struct_as_int: true,

diff --git a/compiler/rustc_target/src/spec/redox_base.rs b/compiler/rustc_target/src/spec/redox_base.rs
@@ -5,7 +5,6 @@ pub fn opts() -> TargetOptions {
         os: "redox".into(),
         env: "relibc".into(),
         dynamic_linking: true,
-        executables: true,
         families: cvs!["unix"],
         has_rpath: true,
         position_independent_executables: true,

diff --git a/compiler/rustc_target/src/spec/riscv32i_unknown_none_elf.rs b/compiler/rustc_target/src/spec/riscv32i_unknown_none_elf.rs
@@ -14,7 +14,6 @@ pub fn target() -> Target {
             cpu: "generic-rv32".into(),
             max_atomic_width: Some(0),
             atomic_cas: false,
-            executables: true,
             panic_strategy: PanicStrategy::Abort,
             relocation_model: RelocModel::Static,
             emit_debug_gdb_scripts: false,

diff --git a/compiler/rustc_target/src/spec/riscv32im_unknown_none_elf.rs b/compiler/rustc_target/src/spec/riscv32im_unknown_none_elf.rs
@@ -15,7 +15,6 @@ pub fn target() -> Target {
             max_atomic_width: Some(0),
             atomic_cas: false,
             features: "+m".into(),
-            executables: true,
             panic_strategy: PanicStrategy::Abort,
             relocation_model: RelocModel::Static,
             emit_debug_gdb_scripts: false,

diff --git a/compiler/rustc_target/src/spec/riscv32imac_unknown_none_elf.rs b/compiler/rustc_target/src/spec/riscv32imac_unknown_none_elf.rs
@@ -14,7 +14,6 @@ pub fn target() -> Target {
             cpu: "generic-rv32".into(),
             max_atomic_width: Some(32),
             features: "+m,+a,+c".into(),
-            executables: true,
             panic_strategy: PanicStrategy::Abort,
             relocation_model: RelocModel::Static,
             emit_debug_gdb_scripts: false,