Merge #1499

1499: processing attribute #[path] of module  r=matklad a=andreevlex

support two cases
- simple name file `foo.rs`
- declaration in mod.rs

#1211 

Co-authored-by: Alexander Andreev <andreevlex.as@gmail.com>

Author: bors[bot]

crates/ra_hir/src/nameres.rs

@@ -1,6 +1,6 @@
 /// This module implements import-resolution/macro expansion algorithm.
 ///
-/// The result of this module is `CrateDefMap`: a datastructure which contains:
+/// The result of this module is `CrateDefMap`: a data structure which contains:
 ///
 ///   * a tree of modules for the crate
 ///   * for each module, a set of items visible in the module (directly declared
@@ -76,7 +76,7 @@ pub use self::{
     raw::ImportId,
 };
 
-/// Contans all top-level defs from a macro-expanded crate
+/// Contains all top-level defs from a macro-expanded crate
 #[derive(Debug, PartialEq, Eq)]
 pub struct CrateDefMap {
     krate: Crate,

crates/ra_hir/src/nameres/collector.rs

@@ -1,6 +1,6 @@
 use arrayvec::ArrayVec;
 use ra_db::FileId;
-use ra_syntax::ast;
+use ra_syntax::{ast, SmolStr};
 use relative_path::RelativePathBuf;
 use rustc_hash::FxHashMap;
 use test_utils::tested_by;
@@ -508,11 +508,17 @@ where
                 }
                 .collect(&*items);
             }
-            // out of line module, resovle, parse and recurse
-            raw::ModuleData::Declaration { name, ast_id } => {
+            // out of line module, resolve, parse and recurse
+            raw::ModuleData::Declaration { name, ast_id, attr_path } => {
                 let ast_id = ast_id.with_file_id(self.file_id);
                 let is_root = self.def_collector.def_map.modules[self.module_id].parent.is_none();
-                match resolve_submodule(self.def_collector.db, self.file_id, name, is_root) {
+                match resolve_submodule(
+                    self.def_collector.db,
+                    self.file_id,
+                    name,
+                    is_root,
+                    attr_path.as_ref(),
+                ) {
                     Ok(file_id) => {
                         let module_id = self.push_child_module(name.clone(), ast_id, Some(file_id));
                         let raw_items = self.def_collector.db.raw_items(file_id.into());
@@ -626,6 +632,7 @@ fn resolve_submodule(
     file_id: HirFileId,
     name: &Name,
     is_root: bool,
+    attr_path: Option<&SmolStr>,
 ) -> Result<FileId, RelativePathBuf> {
     // FIXME: handle submodules of inline modules properly
     let file_id = file_id.original_file(db);
@@ -639,7 +646,13 @@ fn resolve_submodule(
     let file_mod = dir_path.join(format!("{}.rs", name));
     let dir_mod = dir_path.join(format!("{}/mod.rs", name));
     let file_dir_mod = dir_path.join(format!("{}/{}.rs", mod_name, name));
-    let mut candidates = ArrayVec::<[_; 2]>::new();
+    let mut candidates = ArrayVec::<[_; 3]>::new();
+    let file_attr_mod = attr_path.map(|file_path| {
+        let file_attr_mod = dir_path.join(file_path.to_string());
+        candidates.push(file_attr_mod.clone());
+
+        file_attr_mod
+    });
     if is_dir_owner {
         candidates.push(file_mod.clone());
         candidates.push(dir_mod);
@@ -651,7 +664,13 @@ fn resolve_submodule(
     // FIXME: handle ambiguity
     match points_to.next() {
         Some(file_id) => Ok(file_id),
-        None => Err(if is_dir_owner { file_mod } else { file_dir_mod }),
+        None => {
+            if let Some(file_attr_mod) = file_attr_mod {
+                Err(file_attr_mod)
+            } else {
+                Err(if is_dir_owner { file_mod } else { file_dir_mod })
+            }
+        }
     }
 }
 

crates/ra_hir/src/nameres/raw.rs

@@ -3,7 +3,7 @@ use std::{ops::Index, sync::Arc};
 use ra_arena::{impl_arena_id, map::ArenaMap, Arena, RawId};
 use ra_syntax::{
     ast::{self, AttrsOwner, NameOwner},
-    AstNode, AstPtr, SourceFile, TreeArc,
+    AstNode, AstPtr, SmolStr, SourceFile, TreeArc,
 };
 use test_utils::tested_by;
 
@@ -130,7 +130,7 @@ impl_arena_id!(Module);
 
 #[derive(Debug, PartialEq, Eq)]
 pub(super) enum ModuleData {
-    Declaration { name: Name, ast_id: FileAstId<ast::Module> },
+    Declaration { name: Name, ast_id: FileAstId<ast::Module>, attr_path: Option<SmolStr> },
     Definition { name: Name, ast_id: FileAstId<ast::Module>, items: Vec<RawItem> },
 }
 
@@ -255,9 +255,12 @@ impl RawItemsCollector {
             Some(it) => it.as_name(),
             None => return,
         };
+
+        let attr_path = extract_mod_path_attribute(module);
         let ast_id = self.source_ast_id_map.ast_id(module);
         if module.has_semi() {
-            let item = self.raw_items.modules.alloc(ModuleData::Declaration { name, ast_id });
+            let item =
+                self.raw_items.modules.alloc(ModuleData::Declaration { name, ast_id, attr_path });
             self.push_item(current_module, RawItem::Module(item));
             return;
         }
@@ -339,3 +342,16 @@ impl RawItemsCollector {
         .push(item)
     }
 }
+
+fn extract_mod_path_attribute(module: &ast::Module) -> Option<SmolStr> {
+    module.attrs().into_iter().find_map(|attr| {
+        attr.as_key_value().and_then(|(name, value)| {
+            let is_path = name == "path";
+            if is_path {
+                Some(value)
+            } else {
+                None
+            }
+        })
+    })
+}

crates/ra_hir/src/nameres/tests.rs

@@ -2,6 +2,7 @@ mod macros;
 mod globs;
 mod incremental;
 mod primitives;
+mod mods;
 
 use std::sync::Arc;
 
@@ -312,83 +313,6 @@ fn edition_2015_imports() {
     "###);
 }
 
-#[test]
-fn module_resolution_works_for_non_standard_filenames() {
-    let map = def_map_with_crate_graph(
-        "
-        //- /my_library.rs
-        mod foo;
-        use self::foo::Bar;
-
-        //- /foo/mod.rs
-        pub struct Bar;
-        ",
-        crate_graph! {
-            "my_library": ("/my_library.rs", []),
-        },
-    );
-
-    assert_snapshot_matches!(map, @r###"
-        ⋮crate
-        ⋮Bar: t v
-        ⋮foo: t
-        ⋮
-        ⋮crate::foo
-        ⋮Bar: t v
-    "###);
-}
-
-#[test]
-fn module_resolution_works_for_raw_modules() {
-    let map = def_map_with_crate_graph(
-        "
-        //- /library.rs
-        mod r#async;
-        use self::r#async::Bar;
-
-        //- /async.rs
-        pub struct Bar;
-        ",
-        crate_graph! {
-            "library": ("/library.rs", []),
-        },
-    );
-
-    assert_snapshot_matches!(map, @r###"
-        ⋮crate
-        ⋮Bar: t v
-        ⋮async: t
-        ⋮
-        ⋮crate::async
-        ⋮Bar: t v
-    "###);
-}
-
-#[test]
-fn name_res_works_for_broken_modules() {
-    covers!(name_res_works_for_broken_modules);
-    let map = def_map(
-        "
-        //- /lib.rs
-        mod foo // no `;`, no body
-
-        use self::foo::Baz;
-
-        //- /foo/mod.rs
-        pub mod bar;
-
-        pub use self::bar::Baz;
-
-        //- /foo/bar.rs
-        pub struct Baz;
-        ",
-    );
-    assert_snapshot_matches!(map, @r###"
-        ⋮crate
-        ⋮Baz: _
-    "###);
-}
-
 #[test]
 fn item_map_using_self() {
     let map = def_map(
@@ -581,22 +505,3 @@ fn values_dont_shadow_extern_crates() {
         ⋮foo: v
     "###);
 }
-
-#[test]
-fn unresolved_module_diagnostics() {
-    let diagnostics = MockDatabase::with_files(
-        r"
-        //- /lib.rs
-        mod foo;
-        mod bar;
-        mod baz {}
-        //- /foo.rs
-        ",
-    )
-    .diagnostics();
-
-    assert_snapshot_matches!(diagnostics, @r###"
-"mod bar;": unresolved module
-"###
-    );
-}