Auto merge of #152875 - cuviper:beta-next, r=cuviper

[beta] backports

- Consider captures to be used by closures that unwind #152103
- Fix feature gating for new `try bikeshed` expressions #152519
- reject inline const patterns pre-expansion #152548
- layout_of unexpected rigid alias delayed bug #152575
- resolve: Disable an assert that no longer holds #152711

r? cuviper

Author: bors

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -335,15 +335,11 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
     fn visit_expr(&mut self, e: &'a ast::Expr) {
         match e.kind {
             ast::ExprKind::TryBlock(_, None) => {
+                // `try { ... }` is old and is only gated post-expansion here.
                 gate!(&self, try_blocks, e.span, "`try` expression is experimental");
             }
             ast::ExprKind::TryBlock(_, Some(_)) => {
-                gate!(
-                    &self,
-                    try_blocks_heterogeneous,
-                    e.span,
-                    "`try bikeshed` expression is experimental"
-                );
+                // `try_blocks_heterogeneous` is new, and gated pre-expansion instead.
             }
             ast::ExprKind::Lit(token::Lit {
                 kind: token::LitKind::Float | token::LitKind::Integer,
@@ -505,6 +501,7 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
         half_open_range_patterns_in_slices,
         "half-open range patterns in slices are unstable"
     );
+    gate_all!(try_blocks_heterogeneous, "`try bikeshed` expression is experimental");
     gate_all!(yeet_expr, "`do yeet` expression is experimental");
     gate_all!(const_closures, "const closures are experimental");
     gate_all!(builtin_syntax, "`builtin #` syntax is unstable");

compiler/rustc_mir_transform/src/liveness.rs

@@ -1286,6 +1286,7 @@ impl<'tcx> Visitor<'tcx> for TransferFunction<'_, 'tcx> {
             TerminatorKind::Return
             | TerminatorKind::Yield { .. }
             | TerminatorKind::Goto { target: START_BLOCK } // Inserted for the `FnMut` case.
+            | TerminatorKind::Call { target: None, .. } // unwinding could be caught
                 if self.capture_kind != CaptureKind::None =>
             {
                 // All indirect captures have an effect on the environment, so we mark them as live.

compiler/rustc_parse/src/parser/expr.rs

@@ -1521,7 +1521,7 @@ impl<'a> Parser<'a> {
                     },
                 )
             } else if this.check_inline_const(0) {
-                this.parse_const_block(lo)
+                this.parse_const_block(lo, false)
             } else if this.may_recover() && this.is_do_catch_block() {
                 this.recover_do_catch()
             } else if this.is_try_block() {

compiler/rustc_parse/src/parser/mod.rs

@@ -1315,7 +1315,7 @@ impl<'a> Parser<'a> {
     }
 
     /// Parses inline const expressions.
-    fn parse_const_block(&mut self, span: Span) -> PResult<'a, Box<Expr>> {
+    fn parse_const_block(&mut self, span: Span, pat: bool) -> PResult<'a, Box<Expr>> {
         self.expect_keyword(exp!(Const))?;
         let (attrs, blk) = self.parse_inner_attrs_and_block(None)?;
         let anon_const = AnonConst {
@@ -1324,7 +1324,18 @@ impl<'a> Parser<'a> {
             mgca_disambiguation: MgcaDisambiguation::AnonConst,
         };
         let blk_span = anon_const.value.span;
-        let kind = ExprKind::ConstBlock(anon_const);
+        let kind = if pat {
+            let guar = self
+                .dcx()
+                .struct_span_err(blk_span, "const blocks cannot be used as patterns")
+                .with_help(
+                    "use a named `const`-item or an `if`-guard (`x if x == const { ... }`) instead",
+                )
+                .emit();
+            ExprKind::Err(guar)
+        } else {
+            ExprKind::ConstBlock(anon_const)
+        };
         Ok(self.mk_expr_with_attrs(span.to(blk_span), kind, attrs))
     }
 

compiler/rustc_parse/src/parser/pat.rs

@@ -785,10 +785,8 @@ impl<'a> Parser<'a> {
         } else if self.eat_keyword(exp!(Box)) {
             self.parse_pat_box()?
         } else if self.check_inline_const(0) {
-            // Parse `const pat`.
-            // NOTE: This will always error later during AST lowering because
-            // inline const cannot be used as patterns.
-            let const_expr = self.parse_const_block(lo.to(self.token.span))?;
+            // Parse `const pat`
+            let const_expr = self.parse_const_block(lo.to(self.token.span), true)?;
 
             if let Some(re) = self.parse_range_end() {
                 self.parse_pat_range_begin_with(const_expr, re)?
@@ -1283,7 +1281,7 @@ impl<'a> Parser<'a> {
             .then_some(self.prev_token.span);
 
         let bound = if self.check_inline_const(0) {
-            self.parse_const_block(self.token.span)
+            self.parse_const_block(self.token.span, true)
         } else if self.check_path() {
             let lo = self.token.span;
             let (qself, path) = if self.eat_lt() {

compiler/rustc_resolve/src/imports.rs

@@ -366,6 +366,8 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         // - A glob decl is overwritten by its clone after setting ambiguity in it.
         //   FIXME: avoid this by removing `warn_ambiguity`, or by triggering glob re-fetch
         //   with the same decl in some way.
+        // - A glob decl is overwritten by a glob decl with larger visibility.
+        //   FIXME: avoid this by updating this visibility in place.
         // - A glob decl is overwritten by a glob decl re-fetching an
         //   overwritten decl from other module (the recursive case).
         // Here we are detecting all such re-fetches and overwrite old decls
@@ -379,7 +381,8 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             // FIXME: reenable the asserts when `warn_ambiguity` is removed (#149195).
             // assert_ne!(old_deep_decl, deep_decl);
             // assert!(old_deep_decl.is_glob_import());
-            assert!(!deep_decl.is_glob_import());
+            // FIXME: reenable the assert when visibility is updated in place.
+            // assert!(!deep_decl.is_glob_import());
             if old_glob_decl.ambiguity.get().is_some() && glob_decl.ambiguity.get().is_none() {
                 // Do not lose glob ambiguities when re-fetching the glob.
                 glob_decl.ambiguity.set_unchecked(old_glob_decl.ambiguity.get());

compiler/rustc_ty_utils/src/layout.rs

@@ -777,7 +777,9 @@ fn layout_of_uncached<'tcx>(
             let err = if ty.has_param() || !cx.typing_env.param_env.caller_bounds().is_empty() {
                 LayoutError::TooGeneric(ty)
             } else {
-                unreachable!("invalid rigid alias in layout_of after normalization: {ty:?}");
+                LayoutError::ReferencesError(cx.tcx().dcx().delayed_bug(format!(
+                    "unexpected rigid alias in layout_of after normalization: {ty:?}"
+                )))
             };
             return Err(error(cx, err));
         }

tests/ui/feature-gates/feature-gate-try_blocks_heterogeneous.rs

@@ -6,4 +6,11 @@ pub fn main() {
         x
     };
     assert_eq!(try_result, Some(5));
+
+    // The heterogenous form is new, so is gated even under a `cfg(false)`.
+    // See <https://github.com/rust-lang/rust/issues/152501>
+
+    #[cfg(false)]
+    try bikeshed () {}
+    //~^ error `try bikeshed` expression is experimental
 }

tests/ui/feature-gates/feature-gate-try_blocks_heterogeneous.stderr

@@ -12,6 +12,16 @@ LL | |     };
    = help: add `#![feature(try_blocks_heterogeneous)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error: aborting due to 1 previous error
+error[E0658]: `try bikeshed` expression is experimental
+  --> $DIR/feature-gate-try_blocks_heterogeneous.rs:14:5
+   |
+LL |     try bikeshed () {}
+   |     ^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #149488 <https://github.com/rust-lang/rust/issues/149488> for more information
+   = help: add `#![feature(try_blocks_heterogeneous)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0658`.

tests/ui/imports/overwrite-different-vis-3.rs

@@ -0,0 +1,14 @@
+// Regression test for issue #152606.
+
+//@ check-pass
+
+mod outer {
+    mod inner {
+        use super::*; // should go before the ambiguous glob imports
+    }
+
+    use crate::*;
+    pub use crate::*;
+}
+
+fn main() {}