Make error message clearer about creating new module

#69492

Author: kornelski

src/librustc_parse/parser/diagnostics.rs

@@ -18,6 +18,7 @@ use rustc_span::{MultiSpan, Span, SpanSnippetError, DUMMY_SP};
 
 use log::{debug, trace};
 use std::mem;
+use std::path::PathBuf;
 
 const TURBOFISH: &'static str = "use `::<...>` instead of `<...>` to specify type arguments";
 
@@ -42,9 +43,7 @@ pub(super) fn dummy_arg(ident: Ident) -> Param {
 pub enum Error {
     FileNotFoundForModule {
         mod_name: String,
-        default_path: String,
-        secondary_path: String,
-        dir_path: String,
+        default_path: PathBuf,
     },
     DuplicatePaths {
         mod_name: String,
@@ -60,8 +59,6 @@ impl Error {
             Error::FileNotFoundForModule {
                 ref mod_name,
                 ref default_path,
-                ref secondary_path,
-                ref dir_path,
             } => {
                 let mut err = struct_span_err!(
                     handler,
@@ -71,8 +68,8 @@ impl Error {
                     mod_name,
                 );
                 err.help(&format!(
-                    "name the file either {} or {} inside the directory \"{}\"",
-                    default_path, secondary_path, dir_path,
+                    "to create the module `{}`, create file \"{}\"",
+                    mod_name, default_path.display(),
                 ));
                 err
             }

src/librustc_parse/parser/module.rs

@@ -236,9 +236,7 @@ impl<'a> Parser<'a> {
             }),
             (false, false) => Err(Error::FileNotFoundForModule {
                 mod_name: mod_name.clone(),
-                default_path: default_path_str,
-                secondary_path: secondary_path_str,
-                dir_path: dir_path.display().to_string(),
+                default_path,
             }),
             (true, true) => Err(Error::DuplicatePaths {
                 mod_name: mod_name.clone(),

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: name the file either module_that_doesnt_exist.rs or module_that_doesnt_exist/mod.rs inside the directory "$DIR"
+   = help: to create the module `module_that_doesnt_exist`, create file "$DIR/module_that_doesnt_exist.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: name the file either bar/baz.rs or bar/baz/mod.rs inside the directory "$DIR/auxiliary/foo"
+   = help: to create the module `baz`, create file "$DIR/auxiliary/foo/bar/baz.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: name the file either foo/missing.rs or foo/missing/mod.rs inside the directory "$DIR"
+   = help: to create the module `missing`, create file "$DIR/foo/missing.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: name the file either missing.rs or missing/mod.rs inside the directory "$DIR/foo_inline/inline"
+   = help: to create the module `missing`, create file "$DIR/foo_inline/inline/missing.rs"
 
 error: aborting due to previous error
 

src/test/ui/parser/mod_file_not_exist.rs

@@ -1,7 +1,7 @@
 // ignore-windows
 
 mod not_a_real_file; //~ ERROR file not found for module `not_a_real_file`
-//~^ HELP name the file either not_a_real_file.rs or not_a_real_file/mod.rs inside the directory
+//~^ HELP to create the module `not_a_real_file`, create file "
 
 fn main() {
     assert_eq!(mod_file_aux::bar(), 10);

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: name the file either not_a_real_file.rs or not_a_real_file/mod.rs inside the directory "$DIR"
+   = help: to create the module `not_a_real_file`, create file "$DIR/not_a_real_file.rs"
 
 error: aborting due to previous error
 

src/test/ui/parser/mod_file_not_exist_windows.stderr

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