Further deduplicate type ascription errors

Author: estebank

src/librustc_resolve/late/diagnostics.rs

@@ -936,6 +936,22 @@ impl<'a> LateResolutionVisitor<'a, '_, '_> {
                                     Applicability::MaybeIncorrect,
                                 );
                                 show_label = false;
+                                if self
+                                    .r
+                                    .session
+                                    .parse_sess
+                                    .type_ascription_path_suggestions
+                                    .borrow()
+                                    .contains(&colon_sp)
+                                {
+                                    err.delay_as_bug();
+                                }
+                                self.r
+                                    .session
+                                    .parse_sess
+                                    .type_ascription_path_suggestions
+                                    .borrow_mut()
+                                    .insert(colon_sp);
                             }
                             if let Ok(base_snippet) = base_snippet {
                                 let mut sp = after_colon_sp;

src/test/ui/type/ascription/issue-54516.rs

@@ -3,6 +3,4 @@ use std::collections::BTreeMap;
 fn main() {
     println!("{}", std::mem:size_of::<BTreeMap<u32, u32>>());
     //~^ ERROR casts cannot be followed by a function call
-    //~| ERROR expected value, found module `std::mem` [E0423]
-    //~| ERROR cannot find type `size_of` in this scope [E0412]
 }

src/test/ui/type/ascription/issue-54516.stderr

@@ -8,23 +8,5 @@ LL |     println!("{}", std::mem:size_of::<BTreeMap<u32, u32>>());
    |
    = note: `#![feature(type_ascription)]` lets you annotate an expression with a type: `<expr>: <type>`
 
-error[E0423]: expected value, found module `std::mem`
-  --> $DIR/issue-54516.rs:4:20
-   |
-LL |     println!("{}", std::mem:size_of::<BTreeMap<u32, u32>>());
-   |                    ^^^^^^^^- help: maybe you meant to write a path separator here: `::`
-   |                    |
-   |                    not a value
-
-error[E0412]: cannot find type `size_of` in this scope
-  --> $DIR/issue-54516.rs:4:29
-   |
-LL |     println!("{}", std::mem:size_of::<BTreeMap<u32, u32>>());
-   |                            -^^^^^^^ not found in this scope
-   |                            |
-   |                            help: maybe you meant to write a path separator here: `::`
-
-error: aborting due to 3 previous errors
+error: aborting due to previous error
 
-Some errors have detailed explanations: E0412, E0423.
-For more information about an error, try `rustc --explain E0412`.

src/test/ui/type/ascription/issue-60933.rs

@@ -1,6 +1,4 @@
 fn main() {
     let u: usize = std::mem:size_of::<u32>();
     //~^ ERROR casts cannot be followed by a function call
-    //~| ERROR expected value, found module `std::mem` [E0423]
-    //~| ERROR cannot find type `size_of` in this scope [E0412]
 }

src/test/ui/type/ascription/issue-60933.stderr

@@ -8,23 +8,5 @@ LL |     let u: usize = std::mem:size_of::<u32>();
    |
    = note: `#![feature(type_ascription)]` lets you annotate an expression with a type: `<expr>: <type>`
 
-error[E0423]: expected value, found module `std::mem`
-  --> $DIR/issue-60933.rs:2:20
-   |
-LL |     let u: usize = std::mem:size_of::<u32>();
-   |                    ^^^^^^^^- help: maybe you meant to write a path separator here: `::`
-   |                    |
-   |                    not a value
-
-error[E0412]: cannot find type `size_of` in this scope
-  --> $DIR/issue-60933.rs:2:29
-   |
-LL |     let u: usize = std::mem:size_of::<u32>();
-   |                            -^^^^^^^ not found in this scope
-   |                            |
-   |                            help: maybe you meant to write a path separator here: `::`
-
-error: aborting due to 3 previous errors
+error: aborting due to previous error
 
-Some errors have detailed explanations: E0412, E0423.
-For more information about an error, try `rustc --explain E0412`.