Rollup merge of #63289 - kornelski:missingcrate, r=zackmdavis

Don't recommend `extern crate` syntax

`extern crate` syntax is not a good recommendation any more, so I've changed it to just print a suggested crate name.

Author: Centril

src/librustc_resolve/lib.rs

@@ -4084,7 +4084,7 @@ impl<'a> Resolver<'a> {
                                 )),
                             )
                         } else if !ident.is_reserved() {
-                            (format!("maybe a missing `extern crate {};`?", ident), None)
+                            (format!("maybe a missing crate `{}`?", ident), None)
                         } else {
                             // the parser will already have complained about the keyword being used
                             return PathResult::NonModule(PartialRes::new(Res::Err));

src/test/ui/error-codes/E0432.stderr

@@ -2,7 +2,7 @@ error[E0432]: unresolved import `something`
   --> $DIR/E0432.rs:1:5
    |
 LL | use something::Foo;
-   |     ^^^^^^^^^ maybe a missing `extern crate something;`?
+   |     ^^^^^^^^^ maybe a missing crate `something`?
 
 error: aborting due to previous error
 

src/test/ui/extern-prelude-fail.stderr

@@ -2,13 +2,13 @@ error[E0432]: unresolved import `extern_prelude`
   --> $DIR/extern-prelude-fail.rs:7:9
    |
 LL |     use extern_prelude::S;
-   |         ^^^^^^^^^^^^^^ maybe a missing `extern crate extern_prelude;`?
+   |         ^^^^^^^^^^^^^^ maybe a missing crate `extern_prelude`?
 
-error[E0433]: failed to resolve: maybe a missing `extern crate extern_prelude;`?
+error[E0433]: failed to resolve: maybe a missing crate `extern_prelude`?
   --> $DIR/extern-prelude-fail.rs:8:15
    |
 LL |     let s = ::extern_prelude::S;
-   |               ^^^^^^^^^^^^^^ maybe a missing `extern crate extern_prelude;`?
+   |               ^^^^^^^^^^^^^^ maybe a missing crate `extern_prelude`?
 
 error: aborting due to 2 previous errors
 

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

@@ -2,13 +2,13 @@ error[E0432]: unresolved import `core`
   --> $DIR/feature-gate-extern_absolute_paths.rs:1:5
    |
 LL | use core::default;
-   |     ^^^^ maybe a missing `extern crate core;`?
+   |     ^^^^ maybe a missing crate `core`?
 
-error[E0433]: failed to resolve: maybe a missing `extern crate core;`?
+error[E0433]: failed to resolve: maybe a missing crate `core`?
   --> $DIR/feature-gate-extern_absolute_paths.rs:4:19
    |
 LL |     let _: u8 = ::core::default::Default();
-   |                   ^^^^ maybe a missing `extern crate core;`?
+   |                   ^^^^ maybe a missing crate `core`?
 
 error: aborting due to 2 previous errors
 

src/test/ui/import3.stderr

@@ -2,7 +2,7 @@ error[E0432]: unresolved import `main`
   --> $DIR/import3.rs:2:5
    |
 LL | use main::bar;
-   |     ^^^^ maybe a missing `extern crate main;`?
+   |     ^^^^ maybe a missing crate `main`?
 
 error: aborting due to previous error
 

src/test/ui/imports/issue-53269.stderr

@@ -2,7 +2,7 @@ error[E0432]: unresolved import `nonexistent_module`
   --> $DIR/issue-53269.rs:6:9
    |
 LL |     use nonexistent_module::mac;
-   |         ^^^^^^^^^^^^^^^^^^ maybe a missing `extern crate nonexistent_module;`?
+   |         ^^^^^^^^^^^^^^^^^^ maybe a missing crate `nonexistent_module`?
 
 error[E0659]: `mac` is ambiguous (`macro_rules` vs non-`macro_rules` from other module)
   --> $DIR/issue-53269.rs:8:5

src/test/ui/imports/issue-55457.stderr

@@ -11,7 +11,7 @@ error[E0432]: unresolved import `non_existent`
   --> $DIR/issue-55457.rs:2:5
    |
 LL | use non_existent::non_existent;
-   |     ^^^^^^^^^^^^ maybe a missing `extern crate non_existent;`?
+   |     ^^^^^^^^^^^^ maybe a missing crate `non_existent`?
 
 error: cannot determine resolution for the derive macro `NonExistent`
   --> $DIR/issue-55457.rs:5:10

src/test/ui/imports/unresolved-imports-used.stderr

@@ -8,7 +8,7 @@ error[E0432]: unresolved import `foo`
   --> $DIR/unresolved-imports-used.rs:10:5
    |
 LL | use foo::bar;
-   |     ^^^ maybe a missing `extern crate foo;`?
+   |     ^^^ maybe a missing crate `foo`?
 
 error[E0603]: function `quz` is private
   --> $DIR/unresolved-imports-used.rs:8:10

src/test/ui/issues/issue-1697.rs

@@ -1,6 +1,6 @@
 // Testing that we don't fail abnormally after hitting the errors
 
 use unresolved::*; //~ ERROR unresolved import `unresolved` [E0432]
-                   //~^ maybe a missing `extern crate unresolved;`?
+                   //~^ maybe a missing crate `unresolved`?
 
 fn main() {}

src/test/ui/issues/issue-1697.stderr

@@ -2,7 +2,7 @@ error[E0432]: unresolved import `unresolved`
   --> $DIR/issue-1697.rs:3:5
    |
 LL | use unresolved::*;
-   |     ^^^^^^^^^^ maybe a missing `extern crate unresolved;`?
+   |     ^^^^^^^^^^ maybe a missing crate `unresolved`?
 
 error: aborting due to previous error