Module Resolution Fixes

src/modules.rs

@@ -92,11 +92,49 @@ pub(crate) enum ModuleResolutionErrorKind {
 #[derive(Clone)]
 enum SubModKind<'a, 'ast> {
     /// `mod foo;`
+    ///
+    /// Can optionally specify a path attribute to explicitly set the module path.
+    /// ```ignore
+    /// mod foo; // resolves to `./foo.rs` or `./foo/mod.rs`
+    ///
+    /// #[path = "baz.rs"]
+    /// mod foo; // explicitly resolves to `./baz.rs`
+    /// ```
     External(PathBuf, DirectoryOwnership, Module<'ast>),
-    /// `mod foo;` with multiple sources.
+    /// `mod foo;` with multiple `#[cfg_attr]` sources.
+    ///
+    /// ```ignore
+    /// #[cfg_attr(unix, path = "unix.rs")]
+    /// #[cfg_attr(not(unix), path = "not_unix.rs")]
+    /// mod foo; // explicitly resolves to both `./unix.rs` and `./not_unix.rs`
+    /// ```
     MultiExternal(Vec<(PathBuf, DirectoryOwnership, Module<'ast>)>),
     /// `mod foo {}`
+    ///
+    /// Can optionally specify a path attribute that changes resolution for nested modules.
+    /// ```ignore
+    /// mod foo {
+    ///     mod baz; // resolves to `./foo/baz.rs` or `./foo/baz/mod.rs`
+    /// }
+    ///
+    /// #[path = "bar"]
+    /// mod foo {
+    ///     mod baz; // resolves to  `./bar/baz.rs` or `./bar/baz/mod.rs`
+    /// }
+    /// ```
     Internal(&'a ast::Item),
+    /// `mod foo {}` with multiple `#[cfg_attr]` sources.
+    ///
+    /// ```ignore
+    /// #[cfg_attr(unix, path = "unix")]
+    /// #[cfg_attr(not(unix), path = "not_unix")]
+    /// mod foo {
+    ///     // explicitly resolves to `./unix/baz.rs` or `./unix/baz/mod.rs`
+    ///     // and `./not_unix/baz.rs` or `./not_unix/baz/mod.rs`
+    ///     mod baz;
+    /// }
+    /// ```
+    MultiInternal(Vec<PathBuf>),
 }
 
 impl<'ast, 'psess, 'c> ModResolver<'ast, 'psess> {
@@ -279,7 +317,24 @@ impl<'ast, 'psess, 'c> ModResolver<'ast, 'psess> {
             self.find_external_module(item.kind.ident().unwrap(), &item.attrs, sub_mod)
         } else {
             // An internal module (`mod foo { /* ... */ }`);
-            Ok(Some(SubModKind::Internal(item)))
+            let mut path_visitor = visitor::PathVisitor::default();
+            for attr in item.attrs.iter() {
+                if let Some(meta) = attr.meta() {
+                    path_visitor.visit_meta_item(&meta)
+                }
+            }
+
+            let cfg_attr_paths = path_visitor
+                .paths()
+                .iter()
+                .map(|path| self.directory.path.join(path))
+                .collect::<Vec<_>>();
+
+            if cfg_attr_paths.is_empty() {
+                Ok(Some(SubModKind::Internal(item)))
+            } else {
+                Ok(Some(SubModKind::MultiInternal(cfg_attr_paths)))
+            }
         }
     }
 
@@ -332,6 +387,16 @@ impl<'ast, 'psess, 'c> ModResolver<'ast, 'psess> {
                 }
                 Ok(())
             }
+            SubModKind::MultiInternal(cfg_attr_paths) => {
+                for path in cfg_attr_paths {
+                    let directory = Directory {
+                        path: path,
+                        ownership: DirectoryOwnership::UnownedViaBlock,
+                    };
+                    self.visit_sub_mod_after_directory_update(sub_mod.clone(), Some(directory))?;
+                }
+                Ok(())
+            }
         }
     }
 

src/test/mod_resolver.rs

@@ -80,3 +80,37 @@ fn fallback_and_try_to_resolve_external_submod_relative_to_current_dir_path() {
         ],
     )
 }
+
+#[test]
+fn inline_modules_with_path_attributes() {
+    verify_mod_resolution(
+        "tests/mod-resolver/inline_module_with_path_attribute/main.rs",
+        &[
+            "tests/mod-resolver/inline_module_with_path_attribute/bravo/charlie.rs",
+            "tests/mod-resolver/inline_module_with_path_attribute/bravo/echo/foxtrot/mod.rs",
+            "tests/mod-resolver/inline_module_with_path_attribute/bravo/hotel/india/juliet.rs",
+            "tests/mod-resolver/inline_module_with_path_attribute/bravo/hotel/india/lima.rs",
+            "tests/mod-resolver/inline_module_with_path_attribute/mike/november.rs",
+            "tests/mod-resolver/inline_module_with_path_attribute/oscar/papa.rs",
+            "tests/mod-resolver/inline_module_with_path_attribute/tango.rs",
+        ],
+    )
+}
+
+#[test]
+fn cfg_attr_path_on_inline_module() {
+    verify_mod_resolution(
+        "tests/mod-resolver/issue-7038/lib.rs",
+        &[
+            "tests/mod-resolver/issue-7038/meow/wasm/dog/woof.rs",
+            "tests/mod-resolver/issue-7038/meow/wasm/mrrp.rs",
+            "tests/mod-resolver/issue-7038/meow/wasm/y.rs",
+            "tests/mod-resolver/issue-7038/meow_unix/dog/woof.rs",
+            "tests/mod-resolver/issue-7038/meow_unix/mrrp.rs",
+            "tests/mod-resolver/issue-7038/meow_unix/y.rs",
+            "tests/mod-resolver/issue-7038/meow_windows/dog/woof.rs",
+            "tests/mod-resolver/issue-7038/meow_windows/mrrp/mod.rs",
+            "tests/mod-resolver/issue-7038/meow_windows/y.rs",
+        ],
+    )
+}

tests/mod-resolver/inline_module_with_path_attribute/bravo/charlie.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("inline_mod_alpha->bravo/charlie.rs")
+}

tests/mod-resolver/inline_module_with_path_attribute/bravo/echo/foxtrot/mod.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("inline_mod_alpha->inline_mod_delta->bravo/echo/fotxtrot/mod.rs")
+}

tests/mod-resolver/inline_module_with_path_attribute/bravo/hotel/india/juliet.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("inline_mod_alpha->inline_mod_golf->bravo/hotel/india/juliet.rs")
+}

tests/mod-resolver/inline_module_with_path_attribute/bravo/hotel/india/lima.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("inline_mod_alpha->inline_mod_golf->external_mod_kilo->bravo/hotel/india/lima.rs")
+}

tests/mod-resolver/inline_module_with_path_attribute/main.rs

@@ -0,0 +1,38 @@
+#[path = "bravo"]
+mod alpha {
+    mod charlie;
+
+    #[path = "echo"]
+    mod delta {
+        mod foxtrot;
+    }
+
+    #[path = "hotel/india"]
+    mod golf {
+        mod juliet;
+        #[path = "lima.rs"]
+        mod kilo;
+    }
+}
+
+mod mike {
+    mod november;
+}
+
+// Similar to issue https://github.com/rust-lang/rustfmt/issues/4076
+#[path = "oscar"]
+mod oscar {
+    mod papa;
+}
+
+// A more extreme case of https://github.com/rust-lang/rustfmt/issues/3901
+#[path = "."]
+mod quebec {
+    #[path = "."]
+    mod romeo {
+        #[path = "."]
+        mod sierra {
+            mod tango;
+        }
+    }
+}

tests/mod-resolver/inline_module_with_path_attribute/mike/november.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("inline_mod_mike->mike/november.rs")
+}

tests/mod-resolver/inline_module_with_path_attribute/oscar/papa.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("inline_mod_oscar->oscar/papa.rs")
+}

tests/mod-resolver/inline_module_with_path_attribute/tango.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("inline_mod_quebec->inline_mod_romeo->inline_mod_sierra->tango.rs")
+}

tests/mod-resolver/issue-7038/lib.rs

@@ -0,0 +1,14 @@
+#[cfg_attr(unix, path = "meow_unix")]
+#[cfg_attr(windows, path = "meow_windows")]
+#[cfg_attr(wasm, path = "meow/wasm")]
+mod meow {
+    mod mrrp;
+
+    #[path = "y.rs"]
+    mod x;
+
+    #[path = "dog"]
+    mod bark {
+        mod woof;
+    }
+}

tests/mod-resolver/issue-7038/meow/wasm/dog/woof.rs

@@ -0,0 +1 @@
+// meow/wasm/dog/woof.rs

tests/mod-resolver/issue-7038/meow/wasm/mrrp.rs

@@ -0,0 +1 @@
+// meow/wasm/mrrp.rs

tests/mod-resolver/issue-7038/meow/wasm/y.rs

@@ -0,0 +1 @@
+// meow/wasm/y.rs

tests/mod-resolver/issue-7038/meow_unix/dog/woof.rs

@@ -0,0 +1 @@
+// meow_unix/dog/woof.rs

tests/mod-resolver/issue-7038/meow_unix/mrrp.rs

@@ -0,0 +1 @@
+// meow_unix/mrrp.rs

tests/mod-resolver/issue-7038/meow_unix/y.rs

@@ -0,0 +1 @@
+// meow_unix/y.rs

tests/mod-resolver/issue-7038/meow_windows/dog/woof.rs

@@ -0,0 +1 @@
+// meow_windows/dog/woof.rs

tests/mod-resolver/issue-7038/meow_windows/mrrp/mod.rs

@@ -0,0 +1 @@
+// meow_windows/mrrp/mod.rs

tests/mod-resolver/issue-7038/meow_windows/y.rs

@@ -0,0 +1 @@
+// meow_windows/y.rs