feat: Implement module_path macro

crates/base-db/src/input.rs

@@ -272,6 +272,7 @@ impl ReleaseChannel {
     }
 }
 
+#[non_exhaustive]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct CrateData {
     pub root_file_id: FileId,

crates/hir-def/src/data.rs

@@ -748,8 +748,9 @@ impl<'a> AssocItemCollector<'a> {
                     &AstIdWithPath::new(file_id, ast_id, Clone::clone(path)),
                     ctxt,
                     expand_to,
-                    self.expander.krate(),
+                    self.expander.module,
                     resolver,
+                    |module| module.def_map(self.db).path_for_module(self.db, module),
                 ) {
                     Ok(Some(call_id)) => {
                         let res =

crates/hir-def/src/expander.rs

@@ -69,9 +69,12 @@ impl Expander {
 
         let result = self.within_limit(db, |this| {
             let macro_call = this.in_file(&macro_call);
-            match macro_call.as_call_id_with_errors(db.upcast(), this.module.krate(), |path| {
-                resolver(path).map(|it| db.macro_def(it))
-            }) {
+            match macro_call.as_call_id(
+                db.upcast(),
+                this.module,
+                |path| resolver(path).map(|it| db.macro_def(it)),
+                |module| this.module.def_map(db).path_for_module(db, module),
+            ) {
                 Ok(call_id) => call_id,
                 Err(resolve_err) => {
                     unresolved_macro_err = Some(resolve_err);

crates/hir-def/src/lib.rs

@@ -77,7 +77,7 @@ use base_db::{
 use hir_expand::{
     builtin::{BuiltinAttrExpander, BuiltinDeriveExpander, BuiltinFnLikeExpander, EagerExpander},
     db::ExpandDatabase,
-    eager::expand_eager_macro_input,
+    eager::{expand_eager_macro_input, expand_module_path_as_eager},
     impl_intern_lookup,
     name::Name,
     proc_macro::{CustomProcMacroExpander, ProcMacroKind},
@@ -1400,26 +1400,19 @@ pub trait AsMacroCall {
     fn as_call_id(
         &self,
         db: &dyn ExpandDatabase,
-        krate: CrateId,
-        resolver: impl Fn(&path::ModPath) -> Option<MacroDefId> + Copy,
-    ) -> Option<MacroCallId> {
-        self.as_call_id_with_errors(db, krate, resolver).ok()?.value
-    }
-
-    fn as_call_id_with_errors(
-        &self,
-        db: &dyn ExpandDatabase,
-        krate: CrateId,
+        module: ModuleId,
         resolver: impl Fn(&path::ModPath) -> Option<MacroDefId> + Copy,
+        mod_path: impl FnOnce(ModuleId) -> String,
     ) -> Result<ExpandResult<Option<MacroCallId>>, UnresolvedMacro>;
 }
 
 impl AsMacroCall for InFile<&ast::MacroCall> {
-    fn as_call_id_with_errors(
+    fn as_call_id(
         &self,
         db: &dyn ExpandDatabase,
-        krate: CrateId,
+        module: ModuleId,
         resolver: impl Fn(&path::ModPath) -> Option<MacroDefId> + Copy,
+        mod_path: impl FnOnce(ModuleId) -> String,
     ) -> Result<ExpandResult<Option<MacroCallId>>, UnresolvedMacro> {
         let expands_to = hir_expand::ExpandTo::from_call_site(self.value);
         let ast_id = AstId::new(self.file_id, db.ast_id_map(self.file_id).ast_id(self.value));
@@ -1446,9 +1439,10 @@ impl AsMacroCall for InFile<&ast::MacroCall> {
             &path,
             call_site.ctx,
             expands_to,
-            krate,
+            module,
             resolver,
             resolver,
+            mod_path,
         )
     }
 }
@@ -1475,18 +1469,20 @@ fn macro_call_as_call_id(
     call: &AstIdWithPath<ast::MacroCall>,
     call_site: SyntaxContextId,
     expand_to: ExpandTo,
-    krate: CrateId,
+    module: ModuleId,
     resolver: impl Fn(&path::ModPath) -> Option<MacroDefId> + Copy,
+    mod_path: impl FnOnce(ModuleId) -> String,
 ) -> Result<Option<MacroCallId>, UnresolvedMacro> {
     macro_call_as_call_id_with_eager(
         db,
         call.ast_id,
         &call.path,
         call_site,
         expand_to,
-        krate,
+        module,
         resolver,
         resolver,
+        mod_path,
     )
     .map(|res| res.value)
 }
@@ -1497,16 +1493,26 @@ fn macro_call_as_call_id_with_eager(
     path: &path::ModPath,
     call_site: SyntaxContextId,
     expand_to: ExpandTo,
-    krate: CrateId,
+    module: ModuleId,
     resolver: impl FnOnce(&path::ModPath) -> Option<MacroDefId>,
     eager_resolver: impl Fn(&path::ModPath) -> Option<MacroDefId>,
+    mod_path: impl FnOnce(ModuleId) -> String,
 ) -> Result<ExpandResult<Option<MacroCallId>>, UnresolvedMacro> {
     let def = resolver(path).ok_or_else(|| UnresolvedMacro { path: path.clone() })?;
 
     let res = match def.kind {
+        MacroDefKind::BuiltInEager(_, EagerExpander::ModulePath) => expand_module_path_as_eager(
+            db,
+            module.krate,
+            mod_path(module),
+            &ast_id.to_node(db),
+            ast_id,
+            def,
+            call_site,
+        ),
         MacroDefKind::BuiltInEager(..) => expand_eager_macro_input(
             db,
-            krate,
+            module.krate,
             &ast_id.to_node(db),
             ast_id,
             def,
@@ -1516,7 +1522,7 @@ fn macro_call_as_call_id_with_eager(
         _ if def.is_fn_like() => ExpandResult {
             value: Some(def.make_call(
                 db,
-                krate,
+                module.krate,
                 MacroCallKind::FnLike { ast_id, expand_to, eager: None },
                 call_site,
             )),

crates/hir-def/src/macro_expansion_tests/mod.rs

@@ -95,11 +95,16 @@ pub fn identity_when_valid(_attr: TokenStream, item: TokenStream) -> TokenStream
     for macro_call in source_file.syntax().descendants().filter_map(ast::MacroCall::cast) {
         let macro_call = InFile::new(source.file_id, &macro_call);
         let res = macro_call
-            .as_call_id_with_errors(&db, krate, |path| {
-                resolver
-                    .resolve_path_as_macro(&db, path, Some(MacroSubNs::Bang))
-                    .map(|(it, _)| db.macro_def(it))
-            })
+            .as_call_id(
+                &db,
+                resolver.module(),
+                |path| {
+                    resolver
+                        .resolve_path_as_macro(&db, path, Some(MacroSubNs::Bang))
+                        .map(|(it, _)| db.macro_def(it))
+                },
+                |module| def_map.path_for_module(&db, module),
+            )
             .unwrap();
         let macro_call_id = res.value.unwrap();
         let macro_file = MacroFileId { macro_call_id };

crates/hir-def/src/nameres.rs

@@ -63,7 +63,7 @@ use base_db::CrateId;
 use hir_expand::{
     name::Name, proc_macro::ProcMacroKind, ErasedAstId, HirFileId, InFile, MacroCallId, MacroDefId,
 };
-use intern::Symbol;
+use intern::{sym, Symbol};
 use itertools::Itertools;
 use la_arena::Arena;
 use rustc_hash::{FxHashMap, FxHashSet};
@@ -139,6 +139,7 @@ pub struct DefMap {
 /// Data that belongs to a crate which is shared between a crate's def map and all its block def maps.
 #[derive(Clone, Debug, PartialEq, Eq)]
 struct DefMapCrateData {
+    crate_name: Option<Symbol>,
     /// The extern prelude which contains all root modules of external crates that are in scope.
     extern_prelude: FxIndexMap<Name, (CrateRootModuleId, Option<ExternCrateId>)>,
 
@@ -164,6 +165,7 @@ struct DefMapCrateData {
 impl DefMapCrateData {
     fn new(edition: Edition) -> Self {
         Self {
+            crate_name: None,
             extern_prelude: FxIndexMap::default(),
             exported_derives: FxHashMap::default(),
             fn_proc_macro_mapping: FxHashMap::default(),
@@ -186,6 +188,7 @@ impl DefMapCrateData {
             registered_attrs,
             registered_tools,
             unstable_features,
+            crate_name: _,
             rustc_coherence_is_core: _,
             no_core: _,
             no_std: _,
@@ -443,6 +446,28 @@ impl DefMap {
         self.modules.iter()
     }
 
+    pub fn path_for_module(&self, db: &dyn DefDatabase, mut module: ModuleId) -> String {
+        debug_assert!(module.krate == self.krate && module.block == self.block.map(|b| b.block));
+        let mut parts = vec![];
+        if let Some(name) = module.name(db) {
+            parts.push(name.symbol().clone());
+        }
+        while let Some(parent) = module.def_map(db).containing_module(module.local_id) {
+            module = parent;
+            if let Some(name) = module.name(db) {
+                parts.push(name.symbol().clone());
+            }
+            if parts.len() > 10 {
+                break;
+            }
+        }
+        parts.push(match &self.data.crate_name {
+            Some(name) => name.clone(),
+            None => sym::crate_.clone(),
+        });
+        parts.into_iter().rev().format("::").to_string()
+    }
+
     pub fn derive_helpers_in_scope(
         &self,
         id: AstId<ast::Adt>,

crates/hir-def/src/nameres/collector.rs

@@ -247,18 +247,23 @@ impl DefCollector<'_> {
         let _p = tracing::info_span!("seed_with_top_level").entered();
 
         let crate_graph = self.db.crate_graph();
+        let crate_data = Arc::get_mut(&mut self.def_map.data).unwrap();
+        crate_data.crate_name = crate_graph[self.def_map.krate]
+            .display_name
+            .as_ref()
+            .map(|it| it.crate_name().symbol().clone());
+
         let file_id = crate_graph[self.def_map.krate].root_file_id();
         let item_tree = self.db.file_item_tree(file_id.into());
         let attrs = item_tree.top_level_attrs(self.db, self.def_map.krate);
-        let crate_data = Arc::get_mut(&mut self.def_map.data).unwrap();
 
-        let mut process = true;
+        let mut crate_cged_out = false;
 
         // Process other crate-level attributes.
         for attr in &*attrs {
             if let Some(cfg) = attr.cfg() {
                 if self.cfg_options.check(&cfg) == Some(false) {
-                    process = false;
+                    crate_cged_out = true;
                     break;
                 }
             }
@@ -272,6 +277,11 @@ impl DefCollector<'_> {
                         }
                     }
                 }
+                () if *attr_name == sym::crate_name.clone() => {
+                    if let Some(name) = attr.string_value().cloned() {
+                        crate_data.crate_name = Some(name);
+                    }
+                }
                 () if *attr_name == sym::crate_type.clone() => {
                     if attr.string_value() == Some(&sym::proc_dash_macro) {
                         self.is_proc_macro = true;
@@ -337,7 +347,7 @@ impl DefCollector<'_> {
 
         self.inject_prelude();
 
-        if !process {
+        if crate_cged_out {
             return;
         }
 
@@ -1207,8 +1217,9 @@ impl DefCollector<'_> {
                         ast_id,
                         *call_site,
                         *expand_to,
-                        self.def_map.krate,
+                        self.def_map.module_id(directive.module_id),
                         resolver_def_id,
+                        |module| self.def_map.path_for_module(self.db, module),
                     );
                     if let Ok(Some(call_id)) = call_id {
                         self.def_map.modules[directive.module_id]
@@ -1486,7 +1497,7 @@ impl DefCollector<'_> {
                         ast_id,
                         *call_site,
                         *expand_to,
-                        self.def_map.krate,
+                        self.def_map.module_id(directive.module_id),
                         |path| {
                             let resolved_res = self.def_map.resolve_path_fp_with_macro(
                                 self.db,
@@ -1498,6 +1509,7 @@ impl DefCollector<'_> {
                             );
                             resolved_res.resolved_def.take_macros().map(|it| self.db.macro_def(it))
                         },
+                        |module| self.def_map.path_for_module(self.db, module),
                     );
                     if let Err(UnresolvedMacro { path }) = macro_call_as_call_id {
                         self.def_map.diagnostics.push(DefDiagnostic::unresolved_macro_call(
@@ -2351,7 +2363,7 @@ impl ModCollector<'_, '_> {
             &ast_id.path,
             ctxt,
             expand_to,
-            self.def_collector.def_map.krate,
+            self.def_collector.def_map.module_id(self.module_id),
             |path| {
                 path.as_ident().and_then(|name| {
                     let def_map = &self.def_collector.def_map;
@@ -2381,6 +2393,7 @@ impl ModCollector<'_, '_> {
                 );
                 resolved_res.resolved_def.take_macros().map(|it| db.macro_def(it))
             },
+            |module| self.def_collector.def_map.path_for_module(self.def_collector.db, module),
         ) {
             // FIXME: if there were errors, this might've been in the eager expansion from an
             // unresolved macro, so we need to push this into late macro resolution. see fixme above

crates/hir-expand/src/builtin.rs

@@ -1,6 +1,6 @@
 //! Builtin macros and attributes
 #[macro_use]
-mod quote;
+pub(crate) mod quote;
 
 mod attr_macro;
 mod derive_macro;

crates/hir-expand/src/builtin/fn_macro.rs

@@ -116,7 +116,6 @@ register_builtin! {
     (column, Column) => line_expand,
     (file, File) => file_expand,
     (line, Line) => line_expand,
-    (module_path, ModulePath) => module_path_expand,
     (assert, Assert) => assert_expand,
     (stringify, Stringify) => stringify_expand,
     (llvm_asm, LlvmAsm) => asm_expand,
@@ -142,7 +141,10 @@ register_builtin! {
     (include_bytes, IncludeBytes) => include_bytes_expand,
     (include_str, IncludeStr) => include_str_expand,
     (env, Env) => env_expand,
-    (option_env, OptionEnv) => option_env_expand
+    (option_env, OptionEnv) => option_env_expand,
+    // This isn't really eager, we have no inputs, but we abuse the fact how eager macros are
+    // handled in r-a to be able to thread the module path through.
+    (module_path, ModulePath) => module_path_expand
 }
 
 fn mk_pound(span: Span) -> tt::Subtree {
@@ -157,18 +159,6 @@ fn mk_pound(span: Span) -> tt::Subtree {
     )
 }
 
-fn module_path_expand(
-    _db: &dyn ExpandDatabase,
-    _id: MacroCallId,
-    _tt: &tt::Subtree,
-    span: Span,
-) -> ExpandResult<tt::Subtree> {
-    // Just return a dummy result.
-    ExpandResult::ok(quote! {span =>
-         "module::path"
-    })
-}
-
 fn line_expand(
     _db: &dyn ExpandDatabase,
     _id: MacroCallId,
@@ -904,6 +894,18 @@ fn option_env_expand(
     ExpandResult::ok(expanded)
 }
 
+fn module_path_expand(
+    _db: &dyn ExpandDatabase,
+    _id: MacroCallId,
+    tt: &tt::Subtree,
+    span: Span,
+) -> ExpandResult<tt::Subtree> {
+    // Note: The actual implementation of this is in crates\hir-expand\src\eager.rs
+    ExpandResult::ok(quote! {span =>
+         #tt
+    })
+}
+
 fn quote_expand(
     _db: &dyn ExpandDatabase,
     _arg_id: MacroCallId,