Rollup merge of rust-lang#84945 - fee1-dead:E0583-better-message, r=petrochenkov

E0583: Include secondary path in error message

Fixes rust-lang#84819.

Author: GuillaumeGomez

compiler/rustc_expand/src/module.rs

@@ -36,7 +36,7 @@ crate struct ParsedExternalMod {
 pub enum ModError<'a> {
     CircularInclusion(Vec<PathBuf>),
     ModInBlock(Option<Ident>),
-    FileNotFound(Ident, PathBuf),
+    FileNotFound(Ident, PathBuf, PathBuf),
     MultipleCandidates(Ident, PathBuf, PathBuf),
     ParserError(DiagnosticBuilder<'a>),
 }
@@ -219,7 +219,7 @@ pub fn default_submod_path<'a>(
             file_path: secondary_path,
             dir_ownership: DirOwnership::Owned { relative: None },
         }),
-        (false, false) => Err(ModError::FileNotFound(ident, default_path)),
+        (false, false) => Err(ModError::FileNotFound(ident, default_path, secondary_path)),
         (true, true) => Err(ModError::MultipleCandidates(ident, default_path, secondary_path)),
     }
 }
@@ -247,7 +247,7 @@ impl ModError<'_> {
                 }
                 err
             }
-            ModError::FileNotFound(ident, default_path) => {
+            ModError::FileNotFound(ident, default_path, secondary_path) => {
                 let mut err = struct_span_err!(
                     diag,
                     span,
@@ -256,9 +256,10 @@ impl ModError<'_> {
                     ident,
                 );
                 err.help(&format!(
-                    "to create the module `{}`, create file \"{}\"",
+                    "to create the module `{}`, create file \"{}\" or \"{}\"",
                     ident,
                     default_path.display(),
+                    secondary_path.display(),
                 ));
                 err
             }

src/test/ui/error-codes/E0583.stderr

@@ -4,7 +4,7 @@ error[E0583]: file not found for module `module_that_doesnt_exist`
 LL | mod module_that_doesnt_exist;
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: to create the module `module_that_doesnt_exist`, create file "$DIR/module_that_doesnt_exist.rs"
+   = help: to create the module `module_that_doesnt_exist`, create file "$DIR/module_that_doesnt_exist.rs" or "$DIR/module_that_doesnt_exist/mod.rs"
 
 error: aborting due to previous error
 

src/test/ui/invalid-module-declaration/invalid-module-declaration.stderr

@@ -4,7 +4,7 @@ error[E0583]: file not found for module `baz`
 LL | pub mod baz;
    | ^^^^^^^^^^^^
    |
-   = help: to create the module `baz`, create file "$DIR/auxiliary/foo/bar/baz.rs"
+   = help: to create the module `baz`, create file "$DIR/auxiliary/foo/bar/baz.rs" or "$DIR/auxiliary/foo/bar/baz/mod.rs"
 
 error: aborting due to previous error
 

src/test/ui/missing_non_modrs_mod/missing_non_modrs_mod.stderr

@@ -4,7 +4,7 @@ error[E0583]: file not found for module `missing`
 LL | mod missing;
    | ^^^^^^^^^^^^
    |
-   = help: to create the module `missing`, create file "$DIR/foo/missing.rs"
+   = help: to create the module `missing`, create file "$DIR/foo/missing.rs" or "$DIR/foo/missing/mod.rs"
 
 error: aborting due to previous error
 

src/test/ui/missing_non_modrs_mod/missing_non_modrs_mod_inline.stderr

@@ -4,7 +4,7 @@ error[E0583]: file not found for module `missing`
 LL |     mod missing;
    |     ^^^^^^^^^^^^
    |
-   = help: to create the module `missing`, create file "$DIR/foo_inline/inline/missing.rs"
+   = help: to create the module `missing`, create file "$DIR/foo_inline/inline/missing.rs" or "$DIR/foo_inline/inline/missing/mod.rs"
 
 error: aborting due to previous error
 

src/test/ui/parser/mod_file_not_exist.stderr

@@ -4,7 +4,7 @@ error[E0583]: file not found for module `not_a_real_file`
 LL | mod not_a_real_file;
    | ^^^^^^^^^^^^^^^^^^^^
    |
-   = help: to create the module `not_a_real_file`, create file "$DIR/not_a_real_file.rs"
+   = help: to create the module `not_a_real_file`, create file "$DIR/not_a_real_file.rs" or "$DIR/not_a_real_file/mod.rs"
 
 error[E0433]: failed to resolve: use of undeclared crate or module `mod_file_aux`
   --> $DIR/mod_file_not_exist.rs:7:16

src/test/ui/parser/unsafe-mod.stderr

@@ -4,7 +4,7 @@ error[E0583]: file not found for module `n`
 LL | unsafe mod n;
    | ^^^^^^^^^^^^^
    |
-   = help: to create the module `n`, create file "$DIR/n.rs"
+   = help: to create the module `n`, create file "$DIR/n.rs" or "$DIR/n/mod.rs"
 
 error: module cannot be declared unsafe
   --> $DIR/unsafe-mod.rs:1:1

src/test/ui/rfc-2457/mod_file_nonascii_forbidden.stderr

@@ -4,7 +4,7 @@ error[E0583]: file not found for module `řųśť`
 LL | mod řųśť;
    | ^^^^^^^^^
    |
-   = help: to create the module `řųśť`, create file "$DIR/řųśť.rs"
+   = help: to create the module `řųśť`, create file "$DIR/řųśť.rs" or "$DIR/řųśť/mod.rs"
 
 error[E0754]: trying to load file for module `řųśť` with non-ascii identifier name
   --> $DIR/mod_file_nonascii_forbidden.rs:1:5