Add basic custom derive lowering

11 files changed, 152 insertions, 28 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 908319f87..d61343657 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1082,6 +1082,14 @@ dependencies = [
 ]
 
 [[package]]
+name = "ra_proc_macro"
+version = "0.1.0"
+dependencies = [
+ "ra_mbe",
+ "ra_tt",
+]
+
+[[package]]
 name = "ra_prof"
 version = "0.1.0"
 dependencies = [
diff --git a/crates/ra_hir_def/src/lib.rs b/crates/ra_hir_def/src/lib.rs
index 516dd773e..b3e811671 100644
--- a/crates/ra_hir_def/src/lib.rs
+++ b/crates/ra_hir_def/src/lib.rs
@@ -475,6 +475,9 @@ impl AsMacroCall for AstIdWithPath<ast::ModuleItem> {
         resolver: impl Fn(path::ModPath) -> Option<MacroDefId>,
     ) -> Option<MacroCallId> {
         let def = resolver(self.path.clone())?;
-        Some(def.as_lazy_macro(db.upcast(), MacroCallKind::Attr(self.ast_id)).into())
+        Some(
+            def.as_lazy_macro(db.upcast(), MacroCallKind::Attr(self.ast_id, self.path.to_string()))
+                .into(),
+        )
     }
 }
diff --git a/crates/ra_hir_def/src/nameres/collector.rs b/crates/ra_hir_def/src/nameres/collector.rs
index 5b292c250..76be71a30 100644
--- a/crates/ra_hir_def/src/nameres/collector.rs
+++ b/crates/ra_hir_def/src/nameres/collector.rs
@@ -7,6 +7,7 @@ use hir_expand::{
     builtin_derive::find_builtin_derive,
     builtin_macro::find_builtin_macro,
     name::{name, AsName, Name},
+    proc_macro::ProcMacroExpander,
     HirFileId, MacroCallId, MacroDefId, MacroDefKind,
 };
 use ra_cfg::CfgOptions;
@@ -238,6 +239,18 @@ impl DefCollector<'_> {
         self.def_map.modules[module_id].scope.define_legacy_macro(name, mac);
     }
 
+    /// Define a proc macro
+    ///
+    /// A proc macro is similar to normal macro scope, but it would not visiable in legacy textual scoped.
+    /// And unconditionally exported.
+    fn define_proc_macro(&mut self, name: Name, macro_: MacroDefId) {
+        self.update(
+            self.def_map.root,
+            &[(name, PerNs::macros(macro_, Visibility::Public))],
+            Visibility::Public,
+        );
+    }
+
     /// Import macros from `#[macro_use] extern crate`.
     fn import_macros_from_extern_crate(
         &mut self,
@@ -537,8 +550,9 @@ impl DefCollector<'_> {
             true
         });
         attribute_macros.retain(|directive| {
-            if let Some(call_id) =
-                directive.ast_id.as_call_id(self.db, |path| self.resolve_attribute_macro(&path))
+            if let Some(call_id) = directive
+                .ast_id
+                .as_call_id(self.db, |path| self.resolve_attribute_macro(&directive, &path))
             {
                 resolved.push((directive.module_id, call_id, 0));
                 res = ReachedFixedPoint::No;
@@ -562,9 +576,11 @@ impl DefCollector<'_> {
         res
     }
 
-    fn resolve_attribute_macro(&self, path: &ModPath) -> Option<MacroDefId> {
-        // FIXME this is currently super hacky, just enough to support the
-        // built-in derives
+    fn resolve_attribute_macro(
+        &self,
+        directive: &DeriveDirective,
+        path: &ModPath,
+    ) -> Option<MacroDefId> {
         if let Some(name) = path.as_ident() {
             // FIXME this should actually be handled with the normal name
             // resolution; the std lib defines built-in stubs for the derives,
@@ -573,7 +589,15 @@ impl DefCollector<'_> {
                 return Some(def_id);
             }
         }
-        None
+        let resolved_res = self.def_map.resolve_path_fp_with_macro(
+            self.db,
+            ResolveMode::Other,
+            directive.module_id,
+            &path,
+            BuiltinShadowMode::Module,
+        );
+
+        resolved_res.resolved_def.take_macros()
     }
 
     fn collect_macro_expansion(
@@ -776,8 +800,8 @@ impl ModCollector<'_, '_> {
         // FIXME: check attrs to see if this is an attribute macro invocation;
         // in which case we don't add the invocation, just a single attribute
         // macro invocation
-
         self.collect_derives(attrs, def);
+        self.collect_proc_macro(attrs);
 
         let name = def.name.clone();
         let container = ContainerId::ModuleId(module);
@@ -854,6 +878,28 @@ impl ModCollector<'_, '_> {
         }
     }
 
+    fn collect_proc_macro(&mut self, attrs: &Attrs) {
+        if let Some(derive_subtree) = attrs.by_key("proc_macro_derive").tt_values().next() {
+            if let Some(tt) = derive_subtree.token_trees.get(0) {
+                let ident = match &tt {
+                    tt::TokenTree::Leaf(tt::Leaf::Ident(ident)) => ident,
+                    _ => return, // anything else would be an error (which we currently ignore)
+                };
+                let name = ident.as_name();
+                let krate = self.def_collector.def_map.krate;
+                let expander = ProcMacroExpander::new(krate);
+
+                let macro_id = MacroDefId {
+                    ast_id: None,
+                    krate: Some(krate),
+                    kind: MacroDefKind::ProcMacro(expander),
+                };
+
+                self.def_collector.define_proc_macro(name.clone(), macro_id);
+            }
+        }
+    }
+
     fn collect_macro(&mut self, mac: &raw::MacroData) {
         let mut ast_id = AstIdWithPath::new(self.file_id, mac.ast_id, mac.path.clone());
 
diff --git a/crates/ra_hir_expand/src/builtin_derive.rs b/crates/ra_hir_expand/src/builtin_derive.rs
index a5b50a832..7f753bbca 100644
--- a/crates/ra_hir_expand/src/builtin_derive.rs
+++ b/crates/ra_hir_expand/src/builtin_derive.rs
@@ -229,9 +229,12 @@ fn partial_ord_expand(
 mod tests {
     use super::*;
     use crate::{test_db::TestDB, AstId, MacroCallId, MacroCallKind, MacroCallLoc};
+    use name::Name;
     use ra_db::{fixture::WithFixture, SourceDatabase};
 
-    fn expand_builtin_derive(s: &str, expander: BuiltinDeriveExpander) -> String {
+    fn expand_builtin_derive(s: &str, name: Name) -> String {
+        let def = find_builtin_derive(&name).unwrap();
+
         let (db, file_id) = TestDB::with_single_file(&s);
         let parsed = db.parse(file_id);
         let items: Vec<_> =
@@ -239,14 +242,9 @@ mod tests {
 
         let ast_id_map = db.ast_id_map(file_id.into());
 
-        // the first one should be a macro_rules
-        let def =
-            MacroDefId { krate: None, ast_id: None, kind: MacroDefKind::BuiltInDerive(expander) };
+        let attr_id = AstId::new(file_id.into(), ast_id_map.ast_id(&items[0]));
 
-        let loc = MacroCallLoc {
-            def,
-            kind: MacroCallKind::Attr(AstId::new(file_id.into(), ast_id_map.ast_id(&items[0]))),
-        };
+        let loc = MacroCallLoc { def, kind: MacroCallKind::Attr(attr_id, name.to_string()) };
 
         let id: MacroCallId = db.intern_macro(loc).into();
         let parsed = db.parse_or_expand(id.as_file()).unwrap();
@@ -263,7 +261,7 @@ mod tests {
         #[derive(Copy)]
         struct Foo;
 "#,
-            BuiltinDeriveExpander::Copy,
+            name::known::Copy,
         );
 
         assert_eq!(expanded, "impl< >std::marker::CopyforFoo< >{}");
@@ -276,7 +274,7 @@ mod tests {
         #[derive(Copy)]
         struct Foo<A, B>;
 "#,
-            BuiltinDeriveExpander::Copy,
+            name::known::Copy,
         );
 
         assert_eq!(
@@ -292,7 +290,7 @@ mod tests {
         #[derive(Copy)]
         struct Foo<A, B, 'a, 'b>;
 "#,
-            BuiltinDeriveExpander::Copy,
+            name::known::Copy,
         );
 
         // We currently just ignore lifetimes
@@ -310,7 +308,7 @@ mod tests {
         #[derive(Clone)]
         struct Foo<A, B>;
 "#,
-            BuiltinDeriveExpander::Clone,
+            name::known::Clone,
         );
 
         assert_eq!(
diff --git a/crates/ra_hir_expand/src/db.rs b/crates/ra_hir_expand/src/db.rs
index 5a696542f..c2eb75ee5 100644
--- a/crates/ra_hir_expand/src/db.rs
+++ b/crates/ra_hir_expand/src/db.rs
@@ -11,7 +11,7 @@ use ra_syntax::{algo::diff, AstNode, Parse, SyntaxKind::*, SyntaxNode};
 use crate::{
     ast_id_map::AstIdMap, BuiltinDeriveExpander, BuiltinFnLikeExpander, EagerCallLoc, EagerMacroId,
     HirFileId, HirFileIdRepr, LazyMacroId, MacroCallId, MacroCallLoc, MacroDefId, MacroDefKind,
-    MacroFile,
+    MacroFile, ProcMacroExpander,
 };
 
 #[derive(Debug, Clone, Eq, PartialEq)]
@@ -19,6 +19,7 @@ pub enum TokenExpander {
     MacroRules(mbe::MacroRules),
     Builtin(BuiltinFnLikeExpander),
     BuiltinDerive(BuiltinDeriveExpander),
+    ProcMacro(ProcMacroExpander),
 }
 
 impl TokenExpander {
@@ -33,6 +34,7 @@ impl TokenExpander {
             // FIXME switch these to ExpandResult as well
             TokenExpander::Builtin(it) => it.expand(db, id, tt).into(),
             TokenExpander::BuiltinDerive(it) => it.expand(db, id, tt).into(),
+            TokenExpander::ProcMacro(it) => it.expand(db, id, tt).into(),
         }
     }
 
@@ -41,6 +43,7 @@ impl TokenExpander {
             TokenExpander::MacroRules(it) => it.map_id_down(id),
             TokenExpander::Builtin(..) => id,
             TokenExpander::BuiltinDerive(..) => id,
+            TokenExpander::ProcMacro(..) => id,
         }
     }
 
@@ -49,6 +52,7 @@ impl TokenExpander {
             TokenExpander::MacroRules(it) => it.map_id_up(id),
             TokenExpander::Builtin(..) => (id, mbe::Origin::Call),
             TokenExpander::BuiltinDerive(..) => (id, mbe::Origin::Call),
+            TokenExpander::ProcMacro(..) => (id, mbe::Origin::Call),
         }
     }
 }
@@ -130,7 +134,10 @@ pub(crate) fn macro_def(
         MacroDefKind::BuiltInDerive(expander) => {
             Some(Arc::new((TokenExpander::BuiltinDerive(expander), mbe::TokenMap::default())))
         }
-        MacroDefKind::BuiltInEager(_expander) => None,
+        MacroDefKind::BuiltInEager(_) => None,
+        MacroDefKind::ProcMacro(expander) => {
+            Some(Arc::new((TokenExpander::ProcMacro(expander), mbe::TokenMap::default())))
+        }
     }
 }
 
diff --git a/crates/ra_hir_expand/src/eager.rs b/crates/ra_hir_expand/src/eager.rs
index 687d40294..9ff743b9e 100644
--- a/crates/ra_hir_expand/src/eager.rs
+++ b/crates/ra_hir_expand/src/eager.rs
@@ -112,7 +112,8 @@ fn eager_macro_recur(
             }
             MacroDefKind::Declarative
             | MacroDefKind::BuiltIn(_)
-            | MacroDefKind::BuiltInDerive(_) => {
+            | MacroDefKind::BuiltInDerive(_)
+            | MacroDefKind::ProcMacro(_) => {
                 let expanded = lazy_expand(db, &def, curr.with_value(child.clone()))?;
                 // replace macro inside
                 eager_macro_recur(db, expanded, macro_resolver)?
diff --git a/crates/ra_hir_expand/src/hygiene.rs b/crates/ra_hir_expand/src/hygiene.rs
index dfbac494f..182c08eb3 100644
--- a/crates/ra_hir_expand/src/hygiene.rs
+++ b/crates/ra_hir_expand/src/hygiene.rs
@@ -30,6 +30,7 @@ impl Hygiene {
                         MacroDefKind::BuiltIn(_) => None,
                         MacroDefKind::BuiltInDerive(_) => None,
                         MacroDefKind::BuiltInEager(_) => None,
+                        MacroDefKind::ProcMacro(_) => None,
                     }
                 }
                 MacroCallId::EagerMacro(_id) => None,
diff --git a/crates/ra_hir_expand/src/lib.rs b/crates/ra_hir_expand/src/lib.rs
index 6b59ea4c9..ac1d12252 100644
--- a/crates/ra_hir_expand/src/lib.rs
+++ b/crates/ra_hir_expand/src/lib.rs
@@ -11,6 +11,7 @@ pub mod hygiene;
 pub mod diagnostics;
 pub mod builtin_derive;
 pub mod builtin_macro;
+pub mod proc_macro;
 pub mod quote;
 pub mod eager;
 
@@ -27,6 +28,7 @@ use ra_syntax::{
 use crate::ast_id_map::FileAstId;
 use crate::builtin_derive::BuiltinDeriveExpander;
 use crate::builtin_macro::{BuiltinFnLikeExpander, EagerExpander};
+use crate::proc_macro::ProcMacroExpander;
 
 #[cfg(test)]
 mod test_db;
@@ -217,6 +219,7 @@ pub enum MacroDefKind {
     // FIXME: maybe just Builtin and rename BuiltinFnLikeExpander to BuiltinExpander
     BuiltInDerive(BuiltinDeriveExpander),
     BuiltInEager(EagerExpander),
+    ProcMacro(ProcMacroExpander),
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
@@ -228,21 +231,23 @@ pub struct MacroCallLoc {
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum MacroCallKind {
     FnLike(AstId<ast::MacroCall>),
-    Attr(AstId<ast::ModuleItem>),
+    Attr(AstId<ast::ModuleItem>, String),
 }
 
 impl MacroCallKind {
     pub fn file_id(&self) -> HirFileId {
         match self {
             MacroCallKind::FnLike(ast_id) => ast_id.file_id,
-            MacroCallKind::Attr(ast_id) => ast_id.file_id,
+            MacroCallKind::Attr(ast_id, _) => ast_id.file_id,
         }
     }
 
     pub fn node(&self, db: &dyn db::AstDatabase) -> InFile<SyntaxNode> {
         match self {
             MacroCallKind::FnLike(ast_id) => ast_id.with_value(ast_id.to_node(db).syntax().clone()),
-            MacroCallKind::Attr(ast_id) => ast_id.with_value(ast_id.to_node(db).syntax().clone()),
+            MacroCallKind::Attr(ast_id, _) => {
+                ast_id.with_value(ast_id.to_node(db).syntax().clone())
+            }
         }
     }
 
@@ -251,7 +256,7 @@ impl MacroCallKind {
             MacroCallKind::FnLike(ast_id) => {
                 Some(ast_id.to_node(db).token_tree()?.syntax().clone())
             }
-            MacroCallKind::Attr(ast_id) => Some(ast_id.to_node(db).syntax().clone()),
+            MacroCallKind::Attr(ast_id, _) => Some(ast_id.to_node(db).syntax().clone()),
         }
     }
 }
diff --git a/crates/ra_hir_expand/src/proc_macro.rs b/crates/ra_hir_expand/src/proc_macro.rs
new file mode 100644
index 000000000..68c828790
--- /dev/null
+++ b/crates/ra_hir_expand/src/proc_macro.rs
@@ -0,0 +1,32 @@
+//! Proc Macro Expander stub
+
+use crate::{db::AstDatabase, LazyMacroId, MacroCallKind, MacroCallLoc};
+use ra_db::CrateId;
+
+#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
+pub struct ProcMacroExpander {
+    krate: CrateId,
+}
+
+impl ProcMacroExpander {
+    pub fn new(krate: CrateId) -> ProcMacroExpander {
+        ProcMacroExpander { krate }
+    }
+
+    pub fn expand(
+        &self,
+        db: &dyn AstDatabase,
+        id: LazyMacroId,
+        _tt: &tt::Subtree,
+    ) -> Result<tt::Subtree, mbe::ExpandError> {
+        let loc: MacroCallLoc = db.lookup_intern_macro(id);
+        let name = match loc.kind {
+            MacroCallKind::FnLike(_) => return Err(mbe::ExpandError::ConversionError),
+            MacroCallKind::Attr(_, name) => name,
+        };
+
+        dbg!(name);
+
+        unimplemented!()
+    }
+}
diff --git a/crates/ra_hir_ty/src/tests/macros.rs b/crates/ra_hir_ty/src/tests/macros.rs
index 2e309a379..d59e4eea6 100644
--- a/crates/ra_hir_ty/src/tests/macros.rs
+++ b/crates/ra_hir_ty/src/tests/macros.rs
@@ -639,3 +639,26 @@ mod clone {
     );
     assert_eq!("(Wrapper<S>, {unknown})", type_at_pos(&db, pos));
 }
+
+#[test]
+fn infer_custom_derive_simple() {
+    let (db, pos) = TestDB::with_position(
+        r#"
+//- /main.rs crate:main deps:foo
+use foo::Foo;
+
+#[derive(Foo)]
+struct S{}
+
+fn test() {
+    S{}<|>;
+}
+
+//- /lib.rs crate:foo
+#[proc_macro_derive(Foo)]
+pub fn derive_foo(_item: TokenStream) -> TokenStream {    
+}
+"#,
+    );
+    assert_eq!("S", type_at_pos(&db, pos));
+}
diff --git a/crates/ra_mbe/src/syntax_bridge.rs b/crates/ra_mbe/src/syntax_bridge.rs
index e3cde9eed..8e8ae2b29 100644
--- a/crates/ra_mbe/src/syntax_bridge.rs
+++ b/crates/ra_mbe/src/syntax_bridge.rs
@@ -33,7 +33,7 @@ impl TokenTextRange {
 }
 
 /// Maps `tt::TokenId` to the relative range of the original token.
-#[derive(Debug, PartialEq, Eq, Default)]
+#[derive(Debug, PartialEq, Eq, Clone, Default)]
 pub struct TokenMap {
     /// Maps `tt::TokenId` to the *relative* source range.
     entries: Vec<(tt::TokenId, TokenTextRange)>,