From 6ec7255d7b9c96c4cc0feafec6f26a2a9db3b7aa Mon Sep 17 00:00:00 2001 From: Waffle Date: Mon, 13 Sep 2021 16:36:14 +0300 Subject: [PATCH] Highlight the const function if error happened because of a bound on the impl block Currently, for the following code, the compiler produces the errors like the following error: ```rust struct Type impl Type { fn const f() {} } ``` ```text error[E0658]: trait bounds other than `Sized` on const fn parameters are unstable --> ./test.rs:3:6 | 3 | impl Type { | ^ | = note: see issue #57563 for more information = help: add `#![feature(const_fn_trait_bound)]` to the crate attributes to enable ``` This can be confusing (especially to newcomers) since the error mentions "const fn parameters", but highlights only the impl. This commits adds function highlighting, changing the error to the following: ```text error[E0658]: trait bounds other than `Sized` on const fn parameters are unstable --> ./test.rs:3:6 | 3 | impl Type { | ^ 4 | pub const fn f() {} | ---------------- function declared as const here | = note: see issue #57563 for more information = help: add `#![feature(const_fn_trait_bound)]` to the crate attributes to enable ``` --- .../src/transform/check_consts/ops.rs | 13 ++++++++++-- .../consts/min_const_fn/min_const_fn.stderr | 21 ++++++++++++++++--- .../min_const_fn/min_const_fn_dyn.stderr | 6 +++++- 3 files changed, 34 insertions(+), 6 deletions(-) diff --git a/compiler/rustc_const_eval/src/transform/check_consts/ops.rs b/compiler/rustc_const_eval/src/transform/check_consts/ops.rs index 8923d989b29..2a296750838 100644 --- a/compiler/rustc_const_eval/src/transform/check_consts/ops.rs +++ b/compiler/rustc_const_eval/src/transform/check_consts/ops.rs @@ -599,12 +599,21 @@ pub mod ty { } fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> { - feature_err( + let mut builder = feature_err( &ccx.tcx.sess.parse_sess, sym::const_fn_trait_bound, span, "trait bounds other than `Sized` on const fn parameters are unstable", - ) + ); + + match ccx.fn_sig() { + Some(fn_sig) if !fn_sig.span.contains(span) => { + builder.span_label(fn_sig.span, "function declared as const here"); + } + _ => {} + } + + builder } } diff --git a/src/test/ui/consts/min_const_fn/min_const_fn.stderr b/src/test/ui/consts/min_const_fn/min_const_fn.stderr index fcbf39d3869..d1c2a04d6a6 100644 --- a/src/test/ui/consts/min_const_fn/min_const_fn.stderr +++ b/src/test/ui/consts/min_const_fn/min_const_fn.stderr @@ -214,6 +214,9 @@ error[E0658]: trait bounds other than `Sized` on const fn parameters are unstabl | LL | impl Foo { | ^ +LL | +LL | const fn foo(&self) {} + | ------------------- function declared as const here | = note: see issue #57563 for more information = help: add `#![feature(const_fn_trait_bound)]` to the crate attributes to enable @@ -223,6 +226,9 @@ error[E0658]: trait bounds other than `Sized` on const fn parameters are unstabl | LL | impl Foo { | ^ +LL | +LL | const fn foo2(&self) {} + | -------------------- function declared as const here | = note: see issue #57563 for more information = help: add `#![feature(const_fn_trait_bound)]` to the crate attributes to enable @@ -232,6 +238,9 @@ error[E0658]: trait bounds other than `Sized` on const fn parameters are unstabl | LL | impl Foo { | ^ +LL | +LL | const fn foo3(&self) {} + | -------------------- function declared as const here | = note: see issue #57563 for more information = help: add `#![feature(const_fn_trait_bound)]` to the crate attributes to enable @@ -292,7 +301,9 @@ error[E0658]: trait bounds other than `Sized` on const fn parameters are unstabl --> $DIR/min_const_fn.rs:139:41 | LL | const fn really_no_traits_i_mean_it() { (&() as &dyn std::fmt::Debug, ()).1 } - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | ------------------------------------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | | + | function declared as const here | = note: see issue #57563 for more information = help: add `#![feature(const_fn_trait_bound)]` to the crate attributes to enable @@ -301,7 +312,9 @@ error[E0658]: trait bounds other than `Sized` on const fn parameters are unstabl --> $DIR/min_const_fn.rs:139:42 | LL | const fn really_no_traits_i_mean_it() { (&() as &dyn std::fmt::Debug, ()).1 } - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | ------------------------------------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | | + | function declared as const here | = note: see issue #57563 for more information = help: add `#![feature(const_fn_trait_bound)]` to the crate attributes to enable @@ -310,7 +323,9 @@ error[E0658]: trait bounds other than `Sized` on const fn parameters are unstabl --> $DIR/min_const_fn.rs:139:42 | LL | const fn really_no_traits_i_mean_it() { (&() as &dyn std::fmt::Debug, ()).1 } - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | ------------------------------------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | | + | function declared as const here | = note: see issue #57563 for more information = help: add `#![feature(const_fn_trait_bound)]` to the crate attributes to enable diff --git a/src/test/ui/consts/min_const_fn/min_const_fn_dyn.stderr b/src/test/ui/consts/min_const_fn/min_const_fn_dyn.stderr index ce844a2f071..2cad8a862be 100644 --- a/src/test/ui/consts/min_const_fn/min_const_fn_dyn.stderr +++ b/src/test/ui/consts/min_const_fn/min_const_fn_dyn.stderr @@ -1,6 +1,8 @@ error[E0658]: trait bounds other than `Sized` on const fn parameters are unstable --> $DIR/min_const_fn_dyn.rs:9:5 | +LL | const fn no_inner_dyn_trait2(x: Hide) { + | ------------------------------------- function declared as const here LL | x.0.field; | ^^^^^^^^^ | @@ -11,7 +13,9 @@ error[E0658]: trait bounds other than `Sized` on const fn parameters are unstabl --> $DIR/min_const_fn_dyn.rs:12:66 | LL | const fn no_inner_dyn_trait_ret() -> Hide { Hide(HasDyn { field: &0 }) } - | ^^ + | ----------------------------------------- ^^ + | | + | function declared as const here | = note: see issue #57563 for more information = help: add `#![feature(const_fn_trait_bound)]` to the crate attributes to enable