Rollup merge of #71438 - estebank:resolve-sugg-tiny, r=petrochenkov

Tweak some suggestions in `rustc_resolve`

src/test/ui/codemap_tests/two_files.stderr

@@ -4,7 +4,11 @@ error[E0404]: expected trait, found type alias `Bar`
 LL | impl Bar for Baz { }
    |      ^^^ type aliases cannot be used as traits
    |
-   = note: did you mean to use a trait alias?
+help: you might have meant to use `#![feature(trait_alias)]` instead of a `type` alias
+  --> $DIR/two_files_data.rs:5:1
+   |
+LL | type Bar = dyn Foo;
+   | ^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 

src/test/ui/error-codes/E0423.stderr

@@ -45,9 +45,12 @@ error[E0423]: expected value, found struct `T`
   --> $DIR/E0423.rs:14:8
    |
 LL |     if T {} == T {} { println!("Ok"); }
-   |        ^---
-   |        |
-   |        help: surround the struct literal with parenthesis: `(T {})`
+   |        ^
+   |
+help: surround the struct literal with parentheses
+   |
+LL |     if (T {}) == T {} { println!("Ok"); }
+   |        ^    ^
 
 error: aborting due to 5 previous errors
 

src/test/ui/resolve/issue-3907.stderr

@@ -4,7 +4,11 @@ error[E0404]: expected trait, found type alias `Foo`
 LL | impl Foo for S {
    |      ^^^ type aliases cannot be used as traits
    |
-   = note: did you mean to use a trait alias?
+help: you might have meant to use `#![feature(trait_alias)]` instead of a `type` alias
+  --> $DIR/issue-3907.rs:5:1
+   |
+LL | type Foo = dyn issue_3907::Foo;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 help: possible better candidate is found in another module, you can import it into scope
    |
 LL | use issue_3907::Foo;

src/test/ui/resolve/issue-5035.stderr

@@ -16,7 +16,11 @@ LL | impl K for isize {}
    |      type aliases cannot be used as traits
    |      help: a trait with a similar name exists: `I`
    |
-   = note: did you mean to use a trait alias?
+help: you might have meant to use `#![feature(trait_alias)]` instead of a `type` alias
+  --> $DIR/issue-5035.rs:2:1
+   |
+LL | type K = dyn I;
+   | ^^^^^^^^^^^^^^^
 
 error: aborting due to 2 previous errors
 

src/test/ui/resolve/unboxed-closure-sugar-nonexistent-trait.stderr

@@ -10,7 +10,11 @@ error[E0404]: expected trait, found type alias `Typedef`
 LL | fn g<F:Typedef(isize) -> isize>(x: F) {}
    |        ^^^^^^^^^^^^^^^^^^^^^^^ type aliases cannot be used as traits
    |
-   = note: did you mean to use a trait alias?
+help: you might have meant to use `#![feature(trait_alias)]` instead of a `type` alias
+  --> $DIR/unboxed-closure-sugar-nonexistent-trait.rs:4:1
+   |
+LL | type Typedef = isize;
+   | ^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 2 previous errors
 

src/test/ui/struct-literal-variant-in-if.stderr

@@ -46,9 +46,12 @@ error[E0423]: expected value, found struct variant `E::V`
   --> $DIR/struct-literal-variant-in-if.rs:10:13
    |
 LL |     if x == E::V { field } {}
-   |             ^^^^----------
-   |             |
-   |             help: surround the struct literal with parenthesis: `(E::V { field })`
+   |             ^^^^
+   |
+help: surround the struct literal with parentheses
+   |
+LL |     if x == (E::V { field }) {}
+   |             ^              ^
 
 error[E0308]: mismatched types
   --> $DIR/struct-literal-variant-in-if.rs:10:20