Fix mod from inline mod in non-mod-rs.

This works under the assumption that filesystem paths should match mod paths.

When a mod is loaded from within an inline mod, it was using the wrong path when
inside a non-mod-rs file. It was not including the path components from the
non-mod-rs file.

This change also includes:
- Added a test to the run-pass test.
- Added a test to verify the error message when missing.
- Remove unused `non_modrs_mods` for feature gate diagnostics.
- Fixes the run-pass test, it was accidentally removed during stabilization.
- Remove the vestiges of the feature gate tests in `test/ui`.
- Enable the diagnostic test on windows, there didn't seem to be a reason to
  disable it.

Author: ehuss

src/libsyntax/parse/lexer/mod.rs

@@ -1869,7 +1869,6 @@ mod tests {
             missing_fragment_specifiers: Lock::new(FxHashSet::default()),
             raw_identifier_spans: Lock::new(Vec::new()),
             registered_diagnostics: Lock::new(ErrorMap::new()),
-            non_modrs_mods: Lock::new(vec![]),
             buffered_lints: Lock::new(vec![]),
         }
     }

src/libsyntax/parse/mod.rs

@@ -52,9 +52,6 @@ pub struct ParseSess {
     pub raw_identifier_spans: Lock<Vec<Span>>,
     /// The registered diagnostics codes
     crate registered_diagnostics: Lock<ErrorMap>,
-    // Spans where a `mod foo;` statement was included in a non-mod.rs file.
-    // These are used to issue errors if the non_modrs_mods feature is not enabled.
-    pub non_modrs_mods: Lock<Vec<(ast::Ident, Span)>>,
     /// Used to determine and report recursive mod inclusions
     included_mod_stack: Lock<Vec<PathBuf>>,
     code_map: Lrc<SourceMap>,
@@ -81,7 +78,6 @@ impl ParseSess {
             registered_diagnostics: Lock::new(ErrorMap::new()),
             included_mod_stack: Lock::new(vec![]),
             code_map,
-            non_modrs_mods: Lock::new(vec![]),
             buffered_lints: Lock::new(vec![]),
         }
     }

src/libsyntax/parse/parser.rs

@@ -6426,6 +6426,10 @@ impl<'a> Parser<'a> {
             self.directory.path.to_mut().push(&path.as_str());
             self.directory.ownership = DirectoryOwnership::Owned { relative: None };
         } else {
+            if let DirectoryOwnership::Owned{ relative: Some(id) } = self.directory.ownership {
+                self.directory.path.to_mut().push(id.as_str());
+                self.directory.ownership = DirectoryOwnership::Owned { relative: None };
+            }
             self.directory.path.to_mut().push(&id.as_str());
         }
     }
@@ -6533,16 +6537,7 @@ impl<'a> Parser<'a> {
         }
 
         let relative = match self.directory.ownership {
-            DirectoryOwnership::Owned { relative } => {
-                // Push the usage onto the list of non-mod.rs mod uses.
-                // This is used later for feature-gate error reporting.
-                if let Some(cur_file_ident) = relative {
-                    self.sess
-                        .non_modrs_mods.borrow_mut()
-                        .push((cur_file_ident, id_sp));
-                }
-                relative
-            },
+            DirectoryOwnership::Owned { relative } => relative,
             DirectoryOwnership::UnownedViaBlock |
             DirectoryOwnership::UnownedViaMod(_) => None,
         };

src/test/run-pass/non_modrs_mods/foors_mod.rs

@@ -12,3 +12,8 @@
 
 pub mod inner_modrs_mod;
 pub mod inner_foors_mod;
+pub mod block {
+    pub mod block_inner {
+        pub mod block_inner_inner;
+    }
+}

src/test/run-pass/non_modrs_mods/foors_mod/block/block_inner/block_inner_inner.rs

@@ -0,0 +1 @@
+pub fn foo() {}

src/test/run-pass/non_modrs_mods/non_modrs_mods.rs

@@ -0,0 +1,15 @@
+// run-pass
+//
+// ignore-pretty issue #37195
+pub mod modrs_mod;
+pub mod foors_mod;
+#[path = "some_crazy_attr_mod_dir/arbitrary_name.rs"]
+pub mod attr_mod;
+pub fn main() {
+    modrs_mod::inner_modrs_mod::innest::foo();
+    modrs_mod::inner_foors_mod::innest::foo();
+    foors_mod::inner_modrs_mod::innest::foo();
+    foors_mod::inner_foors_mod::innest::foo();
+    foors_mod::block::block_inner::block_inner_inner::foo();
+    attr_mod::inner_modrs_mod::innest::foo();
+}

src/test/ui/missing_non_modrs_mod/foo_inline.rs

@@ -0,0 +1,5 @@
+// ignore-test this is just a helper for the real test in this dir
+
+mod inline {
+    mod missing;
+}

src/test/ui/missing_non_modrs_mod/missing_non_modrs_mod.rs

@@ -8,7 +8,5 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// ignore-windows
-
 mod foo;
 fn main() {}

src/test/ui/missing_non_modrs_mod/missing_non_modrs_mod_inline.rs

@@ -0,0 +1,2 @@
+mod foo_inline;
+fn main() {}

src/test/ui/missing_non_modrs_mod/missing_non_modrs_mod_inline.stderr

@@ -0,0 +1,11 @@
+error[E0583]: file not found for module `missing`
+  --> $DIR/foo_inline.rs:4:9
+   |
+LL |     mod missing;
+   |         ^^^^^^^
+   |
+   = help: name the file either missing.rs or missing/mod.rs inside the directory "$DIR/foo_inline/inline"
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0583`.