diff options
3 files changed, 75 insertions, 2 deletions
diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs index 446e02e4024..22a293d9b50 100644 --- a/compiler/rustc_ast_lowering/src/lib.rs +++ b/compiler/rustc_ast_lowering/src/lib.rs @@ -2034,7 +2034,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { } fn lower_array_length_to_const_arg(&mut self, c: &AnonConst) -> &'hir hir::ConstArg<'hir> { - match c.value.kind { + // We cannot just match on `ExprKind::Underscore` as `(_)` is represented as + // `ExprKind::Paren(ExprKind::Underscore)` and should also be lowered to `GenericArg::Infer` + match c.value.peel_parens().kind { ExprKind::Underscore => { if !self.tcx.features().generic_arg_infer() { feature_err( diff --git a/tests/ui/const-generics/generic_arg_infer/parend_infer.nogate.stderr b/tests/ui/const-generics/generic_arg_infer/parend_infer.nogate.stderr new file mode 100644 index 00000000000..d0a5da9676d --- /dev/null +++ b/tests/ui/const-generics/generic_arg_infer/parend_infer.nogate.stderr @@ -0,0 +1,53 @@ +error[E0658]: const arguments cannot yet be inferred with `_` + --> $DIR/parend_infer.rs:24:16 + | +LL | let c: Foo<_> = Foo::<1>; + | ^ + | + = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information + = help: add `#![feature(generic_arg_infer)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date + +error[E0658]: const arguments cannot yet be inferred with `_` + --> $DIR/parend_infer.rs:26:16 + | +LL | let c: Foo<(_)> = Foo::<1>; + | ^^^ + | + = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information + = help: add `#![feature(generic_arg_infer)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date + +error[E0658]: const arguments cannot yet be inferred with `_` + --> $DIR/parend_infer.rs:28:16 + | +LL | let c: Foo<(((_)))> = Foo::<1>; + | ^^^^^^^ + | + = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information + = help: add `#![feature(generic_arg_infer)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date + +error[E0658]: using `_` for array lengths is unstable + --> $DIR/parend_infer.rs:17:17 + | +LL | let b: [u8; (_)] = [1; (((((_)))))]; + | ^^^ + | + = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information + = help: add `#![feature(generic_arg_infer)]` 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[E0658]: using `_` for array lengths is unstable + --> $DIR/parend_infer.rs:17:28 + | +LL | let b: [u8; (_)] = [1; (((((_)))))]; + | ^^^^^^^^^^^ + | + = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information + = help: add `#![feature(generic_arg_infer)]` 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 5 previous errors + +For more information about this error, try `rustc --explain E0658`. diff --git a/tests/ui/const-generics/generic_arg_infer/parend_infer.rs b/tests/ui/const-generics/generic_arg_infer/parend_infer.rs index 81c42183b38..3dc27a702de 100644 --- a/tests/ui/const-generics/generic_arg_infer/parend_infer.rs +++ b/tests/ui/const-generics/generic_arg_infer/parend_infer.rs @@ -1,7 +1,9 @@ -//@ check-pass +//@[gate] check-pass //@ revisions: gate nogate #![cfg_attr(gate, feature(generic_arg_infer))] +struct Foo<const N: usize>; + fn main() { // AST Types preserve parens for pretty printing reasons. This means // that this is parsed as a `TyKind::Paren(TyKind::Infer)`. Generic @@ -9,4 +11,20 @@ fn main() { // but `TyKind::Infer` wrapped in arbitrarily many `TyKind::Paren`. let a: Vec<(_)> = vec![1_u8]; let a: Vec<(((((_)))))> = vec![1_u8]; + + // AST Exprs similarly preserve parens for pretty printing reasons. + #[rustfmt::skip] + let b: [u8; (_)] = [1; (((((_)))))]; + //[nogate]~^ error: using `_` for array lengths is unstable + //[nogate]~| error: using `_` for array lengths is unstable + let b: [u8; 2] = b; + + // This is the same case as AST types as the parser doesn't distinguish between const + // and type args when they share syntax + let c: Foo<_> = Foo::<1>; + //[nogate]~^ error: const arguments cannot yet be inferred with `_` + let c: Foo<(_)> = Foo::<1>; + //[nogate]~^ error: const arguments cannot yet be inferred with `_` + let c: Foo<(((_)))> = Foo::<1>; + //[nogate]~^ error: const arguments cannot yet be inferred with `_` } |