ast_validation: tweak diagnostic output

src/librustc_ast_passes/ast_validation.rs

@@ -223,21 +223,29 @@ impl<'a> AstValidator<'a> {
 
     fn check_trait_fn_not_async(&self, fn_span: Span, asyncness: Async) {
         if let Async::Yes { span, .. } = asyncness {
-            struct_span_err!(self.session, fn_span, E0706, "trait fns cannot be declared `async`")
-                .span_label(span, "`async` because of this")
-                .note("`async` trait functions are not currently supported")
-                .note(
-                    "consider using the `async-trait` crate: https://crates.io/crates/async-trait",
-                )
-                .emit();
+            struct_span_err!(
+                self.session,
+                fn_span,
+                E0706,
+                "functions in traits cannot be declared `async`"
+            )
+            .span_label(span, "`async` because of this")
+            .note("`async` trait functions are not currently supported")
+            .note("consider using the `async-trait` crate: https://crates.io/crates/async-trait")
+            .emit();
         }
     }
 
     fn check_trait_fn_not_const(&self, constness: Const) {
         if let Const::Yes(span) = constness {
-            struct_span_err!(self.session, span, E0379, "trait fns cannot be declared const")
-                .span_label(span, "trait fns cannot be const")
-                .emit();
+            struct_span_err!(
+                self.session,
+                span,
+                E0379,
+                "functions in traits cannot be declared const"
+            )
+            .span_label(span, "functions in traits cannot be const")
+            .emit();
         }
     }
 
@@ -513,8 +521,11 @@ impl<'a> AstValidator<'a> {
             for param in &generics.params {
                 if let GenericParamKind::Const { .. } = param.kind {
                     self.err_handler()
-                        .struct_span_err(span, "const parameters are not permitted in `const fn`")
-                        .span_label(const_span, "`const fn` because of this")
+                        .struct_span_err(
+                            span,
+                            "const parameters are not permitted in const functions",
+                        )
+                        .span_label(const_span, "`const` because of this")
                         .emit();
                 }
             }

src/test/ui/async-await/async-trait-fn.rs

@@ -1,7 +1,7 @@
 // edition:2018
 trait T {
-    async fn foo() {} //~ ERROR trait fns cannot be declared `async`
-    async fn bar(&self) {} //~ ERROR trait fns cannot be declared `async`
+    async fn foo() {} //~ ERROR functions in traits cannot be declared `async`
+    async fn bar(&self) {} //~ ERROR functions in traits cannot be declared `async`
 }
 
 fn main() {}

src/test/ui/async-await/async-trait-fn.stderr

@@ -1,4 +1,4 @@
-error[E0706]: trait fns cannot be declared `async`
+error[E0706]: functions in traits cannot be declared `async`
   --> $DIR/async-trait-fn.rs:3:5
    |
 LL |     async fn foo() {}
@@ -9,7 +9,7 @@ LL |     async fn foo() {}
    = note: `async` trait functions are not currently supported
    = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
 
-error[E0706]: trait fns cannot be declared `async`
+error[E0706]: functions in traits cannot be declared `async`
   --> $DIR/async-trait-fn.rs:4:5
    |
 LL |     async fn bar(&self) {}

src/test/ui/async-await/edition-deny-async-fns-2015.rs

@@ -16,7 +16,7 @@ impl Foo {
 
 trait Bar {
     async fn foo() {} //~ ERROR `async fn` is not permitted in the 2015 edition
-                      //~^ ERROR trait fns cannot be declared `async`
+                      //~^ ERROR functions in traits cannot be declared `async`
 }
 
 fn main() {

src/test/ui/async-await/edition-deny-async-fns-2015.stderr

@@ -88,7 +88,7 @@ LL |             async fn bar() {}
    = help: set `edition = "2018"` in `Cargo.toml`
    = note: for more on editions, read https://doc.rust-lang.org/edition-guide
 
-error[E0706]: trait fns cannot be declared `async`
+error[E0706]: functions in traits cannot be declared `async`
   --> $DIR/edition-deny-async-fns-2015.rs:18:5
    |
 LL |     async fn foo() {}

src/test/ui/const-generics/const-fn-with-const-param.rs

@@ -2,7 +2,7 @@
 //~^ WARN the feature `const_generics` is incomplete and may cause the compiler to crash
 
 const fn const_u32_identity<const X: u32>() -> u32 {
-    //~^ ERROR const parameters are not permitted in `const fn`
+    //~^ ERROR const parameters are not permitted in const functions
     X
 }
 

src/test/ui/const-generics/const-fn-with-const-param.stderr

@@ -1,10 +1,10 @@
-error: const parameters are not permitted in `const fn`
+error: const parameters are not permitted in const functions
   --> $DIR/const-fn-with-const-param.rs:4:1
    |
 LL |   const fn const_u32_identity<const X: u32>() -> u32 {
    |   ^----
    |   |
-   |  _`const fn` because of this
+   |  _`const` because of this
    | |
 LL | |
 LL | |     X

src/test/ui/consts/const-fn-mismatch.rs

@@ -10,8 +10,10 @@ trait Foo {
 }
 
 impl Foo for u32 {
-    const fn f() -> u32 { 22 }
-    //~^ ERROR trait fns cannot be declared const
+    const fn f() -> u32 {
+        //~^ ERROR functions in traits cannot be declared const
+        22
+    }
 }
 
-fn main() { }
+fn main() {}

src/test/ui/consts/const-fn-mismatch.stderr

@@ -1,8 +1,8 @@
-error[E0379]: trait fns cannot be declared const
+error[E0379]: functions in traits cannot be declared const
   --> $DIR/const-fn-mismatch.rs:13:5
    |
-LL |     const fn f() -> u32 { 22 }
-   |     ^^^^^ trait fns cannot be const
+LL |     const fn f() -> u32 {
+   |     ^^^^^ functions in traits cannot be const
 
 error: aborting due to previous error
 

src/test/ui/consts/const-fn-not-in-trait.rs

@@ -5,9 +5,11 @@
 
 trait Foo {
     const fn f() -> u32;
-    //~^ ERROR trait fns cannot be declared const
-    const fn g() -> u32 { 0 }
-    //~^ ERROR trait fns cannot be declared const
+    //~^ ERROR functions in traits cannot be declared const
+    const fn g() -> u32 {
+        //~^ ERROR functions in traits cannot be declared const
+        0
+    }
 }
 
-fn main() { }
+fn main() {}

src/test/ui/consts/const-fn-not-in-trait.stderr

@@ -1,14 +1,14 @@
-error[E0379]: trait fns cannot be declared const
+error[E0379]: functions in traits cannot be declared const
   --> $DIR/const-fn-not-in-trait.rs:7:5
    |
 LL |     const fn f() -> u32;
-   |     ^^^^^ trait fns cannot be const
+   |     ^^^^^ functions in traits cannot be const
 
-error[E0379]: trait fns cannot be declared const
+error[E0379]: functions in traits cannot be declared const
   --> $DIR/const-fn-not-in-trait.rs:9:5
    |
-LL |     const fn g() -> u32 { 0 }
-   |     ^^^^^ trait fns cannot be const
+LL |     const fn g() -> u32 {
+   |     ^^^^^ functions in traits cannot be const
 
 error: aborting due to 2 previous errors
 

src/test/ui/feature-gates/feature-gate-const_fn.rs

@@ -4,13 +4,13 @@ const fn foo() -> usize { 0 } // ok
 
 trait Foo {
     const fn foo() -> u32; //~ ERROR const fn is unstable
-                           //~| ERROR trait fns cannot be declared const
+                           //~| ERROR functions in traits cannot be declared const
     const fn bar() -> u32 { 0 } //~ ERROR const fn is unstable
-                                //~| ERROR trait fns cannot be declared const
+                                //~| ERROR functions in traits cannot be declared const
 }
 
 impl Foo for u32 {
-    const fn foo() -> u32 { 0 } //~ ERROR trait fns cannot be declared const
+    const fn foo() -> u32 { 0 } //~ ERROR functions in traits cannot be declared const
 }
 
 trait Bar {}

src/test/ui/feature-gates/feature-gate-const_fn.stderr

@@ -1,20 +1,20 @@
-error[E0379]: trait fns cannot be declared const
+error[E0379]: functions in traits cannot be declared const
   --> $DIR/feature-gate-const_fn.rs:6:5
    |
 LL |     const fn foo() -> u32;
-   |     ^^^^^ trait fns cannot be const
+   |     ^^^^^ functions in traits cannot be const
 
-error[E0379]: trait fns cannot be declared const
+error[E0379]: functions in traits cannot be declared const
   --> $DIR/feature-gate-const_fn.rs:8:5
    |
 LL |     const fn bar() -> u32 { 0 }
-   |     ^^^^^ trait fns cannot be const
+   |     ^^^^^ functions in traits cannot be const
 
-error[E0379]: trait fns cannot be declared const
+error[E0379]: functions in traits cannot be declared const
   --> $DIR/feature-gate-const_fn.rs:13:5
    |
 LL |     const fn foo() -> u32 { 0 }
-   |     ^^^^^ trait fns cannot be const
+   |     ^^^^^ functions in traits cannot be const
 
 error[E0658]: const fn is unstable
   --> $DIR/feature-gate-const_fn.rs:6:5

src/test/ui/feature-gates/feature-gate-min_const_fn.rs

@@ -4,13 +4,13 @@ const fn foo() -> usize { 0 } // stabilized
 
 trait Foo {
     const fn foo() -> u32; //~ ERROR const fn is unstable
-                           //~| ERROR trait fns cannot be declared const
+                           //~| ERROR functions in traits cannot be declared const
     const fn bar() -> u32 { 0 } //~ ERROR const fn is unstable
-                                //~| ERROR trait fns cannot be declared const
+                                //~| ERROR functions in traits cannot be declared const
 }
 
 impl Foo for u32 {
-    const fn foo() -> u32 { 0 } //~ ERROR trait fns cannot be declared const
+    const fn foo() -> u32 { 0 } //~ ERROR functions in traits cannot be declared const
 }
 
 trait Bar {}

src/test/ui/feature-gates/feature-gate-min_const_fn.stderr

@@ -1,20 +1,20 @@
-error[E0379]: trait fns cannot be declared const
+error[E0379]: functions in traits cannot be declared const
   --> $DIR/feature-gate-min_const_fn.rs:6:5
    |
 LL |     const fn foo() -> u32;
-   |     ^^^^^ trait fns cannot be const
+   |     ^^^^^ functions in traits cannot be const
 
-error[E0379]: trait fns cannot be declared const
+error[E0379]: functions in traits cannot be declared const
   --> $DIR/feature-gate-min_const_fn.rs:8:5
    |
 LL |     const fn bar() -> u32 { 0 }
-   |     ^^^^^ trait fns cannot be const
+   |     ^^^^^ functions in traits cannot be const
 
-error[E0379]: trait fns cannot be declared const
+error[E0379]: functions in traits cannot be declared const
   --> $DIR/feature-gate-min_const_fn.rs:13:5
    |
 LL |     const fn foo() -> u32 { 0 }
-   |     ^^^^^ trait fns cannot be const
+   |     ^^^^^ functions in traits cannot be const
 
 error[E0658]: const fn is unstable
   --> $DIR/feature-gate-min_const_fn.rs:6:5

src/test/ui/issues/issue-54954.rs

@@ -5,7 +5,7 @@ const ARR_LEN: usize = Tt::const_val::<[i8; 123]>();
 
 trait Tt {
     const fn const_val<T: Sized>() -> usize {
-    //~^ ERROR trait fns cannot be declared const
+        //~^ ERROR functions in traits cannot be declared const
         core::mem::size_of::<T>()
     }
 }

src/test/ui/issues/issue-54954.stderr

@@ -1,8 +1,8 @@
-error[E0379]: trait fns cannot be declared const
+error[E0379]: functions in traits cannot be declared const
   --> $DIR/issue-54954.rs:7:5
    |
 LL |     const fn const_val<T: Sized>() -> usize {
-   |     ^^^^^ trait fns cannot be const
+   |     ^^^^^ functions in traits cannot be const
 
 error[E0283]: type annotations needed
   --> $DIR/issue-54954.rs:3:24

src/test/ui/mismatched_types/const-fn-in-trait.stderr

@@ -1,14 +1,14 @@
-error[E0379]: trait fns cannot be declared const
+error[E0379]: functions in traits cannot be declared const
   --> $DIR/const-fn-in-trait.rs:7:5
    |
 LL |     const fn g();
-   |     ^^^^^ trait fns cannot be const
+   |     ^^^^^ functions in traits cannot be const
 
-error[E0379]: trait fns cannot be declared const
+error[E0379]: functions in traits cannot be declared const
   --> $DIR/const-fn-in-trait.rs:11:5
    |
 LL |     const fn f() -> u32 { 22 }
-   |     ^^^^^ trait fns cannot be const
+   |     ^^^^^ functions in traits cannot be const
 
 error: aborting due to 2 previous errors
 

src/test/ui/parser/fn-header-semantic-fail.rs

@@ -14,26 +14,26 @@ fn main() {
     //~^ ERROR functions cannot be both `const` and `async`
 
     trait X {
-        async fn ft1(); //~ ERROR trait fns cannot be declared `async`
+        async fn ft1(); //~ ERROR functions in traits cannot be declared `async`
         unsafe fn ft2(); // OK.
-        const fn ft3(); //~ ERROR trait fns cannot be declared const
+        const fn ft3(); //~ ERROR functions in traits cannot be declared const
         extern "C" fn ft4(); // OK.
         const async unsafe extern "C" fn ft5();
-        //~^ ERROR trait fns cannot be declared `async`
-        //~| ERROR trait fns cannot be declared const
+        //~^ ERROR functions in traits cannot be declared `async`
+        //~| ERROR functions in traits cannot be declared const
         //~| ERROR functions cannot be both `const` and `async`
     }
 
     struct Y;
     impl X for Y {
-        async fn ft1() {} //~ ERROR trait fns cannot be declared `async`
+        async fn ft1() {} //~ ERROR functions in traits cannot be declared `async`
         //~^ ERROR method `ft1` has an incompatible type for trait
         unsafe fn ft2() {} // OK.
-        const fn ft3() {} //~ ERROR trait fns cannot be declared const
+        const fn ft3() {} //~ ERROR functions in traits cannot be declared const
         extern "C" fn ft4() {}
         const async unsafe extern "C" fn ft5() {}
-        //~^ ERROR trait fns cannot be declared `async`
-        //~| ERROR trait fns cannot be declared const
+        //~^ ERROR functions in traits cannot be declared `async`
+        //~| ERROR functions in traits cannot be declared const
         //~| ERROR method `ft5` has an incompatible type for trait
         //~| ERROR functions cannot be both `const` and `async`
     }

src/test/ui/parser/fn-header-semantic-fail.stderr

@@ -7,7 +7,7 @@ LL |     const async unsafe extern "C" fn ff5() {} // OK.
    |     |     `async` because of this
    |     `const` because of this
 
-error[E0706]: trait fns cannot be declared `async`
+error[E0706]: functions in traits cannot be declared `async`
   --> $DIR/fn-header-semantic-fail.rs:17:9
    |
 LL |         async fn ft1();
@@ -18,19 +18,19 @@ LL |         async fn ft1();
    = note: `async` trait functions are not currently supported
    = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
 
-error[E0379]: trait fns cannot be declared const
+error[E0379]: functions in traits cannot be declared const
   --> $DIR/fn-header-semantic-fail.rs:19:9
    |
 LL |         const fn ft3();
-   |         ^^^^^ trait fns cannot be const
+   |         ^^^^^ functions in traits cannot be const
 
-error[E0379]: trait fns cannot be declared const
+error[E0379]: functions in traits cannot be declared const
   --> $DIR/fn-header-semantic-fail.rs:21:9
    |
 LL |         const async unsafe extern "C" fn ft5();
-   |         ^^^^^ trait fns cannot be const
+   |         ^^^^^ functions in traits cannot be const
 
-error[E0706]: trait fns cannot be declared `async`
+error[E0706]: functions in traits cannot be declared `async`
   --> $DIR/fn-header-semantic-fail.rs:21:9
    |
 LL |         const async unsafe extern "C" fn ft5();
@@ -50,7 +50,7 @@ LL |         const async unsafe extern "C" fn ft5();
    |         |     `async` because of this
    |         `const` because of this
 
-error[E0706]: trait fns cannot be declared `async`
+error[E0706]: functions in traits cannot be declared `async`
   --> $DIR/fn-header-semantic-fail.rs:29:9
    |
 LL |         async fn ft1() {}
@@ -61,19 +61,19 @@ LL |         async fn ft1() {}
    = note: `async` trait functions are not currently supported
    = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
 
-error[E0379]: trait fns cannot be declared const
+error[E0379]: functions in traits cannot be declared const
   --> $DIR/fn-header-semantic-fail.rs:32:9
    |
 LL |         const fn ft3() {}
-   |         ^^^^^ trait fns cannot be const
+   |         ^^^^^ functions in traits cannot be const
 
-error[E0379]: trait fns cannot be declared const
+error[E0379]: functions in traits cannot be declared const
   --> $DIR/fn-header-semantic-fail.rs:34:9
    |
 LL |         const async unsafe extern "C" fn ft5() {}
-   |         ^^^^^ trait fns cannot be const
+   |         ^^^^^ functions in traits cannot be const
 
-error[E0706]: trait fns cannot be declared `async`
+error[E0706]: functions in traits cannot be declared `async`
   --> $DIR/fn-header-semantic-fail.rs:34:9
    |
 LL |         const async unsafe extern "C" fn ft5() {}