4 files changed, 56 insertions, 39 deletions

diff --git a/crates/ra_hir/src/ty/method_resolution.rs b/crates/ra_hir/src/ty/method_resolution.rs
index 37bc3f38c..2282286b0 100644
--- a/crates/ra_hir/src/ty/method_resolution.rs
+++ b/crates/ra_hir/src/ty/method_resolution.rs
@@ -7,17 +7,16 @@ use std::sync::Arc;
 use rustc_hash::FxHashMap;
 
 use crate::{
-    HirDatabase, module_tree::ModuleId, Module, Crate, Name, Function,
+    HirDatabase, module_tree::ModuleId, Module, Crate, Name, Function, Trait,
+    ids::TraitId,
     impl_block::{ImplId, ImplBlock, ImplItem},
-    generics::GenericParams,
-    ty::{AdtDef, Ty}
+    ty::{AdtDef, Ty},
 };
 
 /// This is used as a key for indexing impls.
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub enum TyFingerprint {
-    Adt(AdtDef),
-    // we'll also want to index impls for primitive types etc.
+    Adt(AdtDef), // we'll also want to index impls for primitive types etc.
 }
 
 impl TyFingerprint {
@@ -37,6 +36,7 @@ pub struct CrateImplBlocks {
     /// To make sense of the ModuleIds, we need the source root.
     krate: Crate,
     impls: FxHashMap<TyFingerprint, Vec<(ModuleId, ImplId)>>,
+    impls_by_trait: FxHashMap<TraitId, Vec<(ModuleId, ImplId)>>,
 }
 
 impl CrateImplBlocks {
@@ -60,30 +60,46 @@ impl CrateImplBlocks {
             })
     }
 
+    pub fn lookup_impl_blocks_for_trait<'a>(
+        &'a self,
+        db: &'a impl HirDatabase,
+        tr: &Trait,
+    ) -> impl Iterator<Item = (Module, ImplBlock)> + 'a {
+        let id = tr.id;
+        self.impls_by_trait
+            .get(&id)
+            .into_iter()
+            .flat_map(|i| i.iter())
+            .map(move |(module_id, impl_id)| {
+                let module = Module {
+                    krate: self.krate,
+                    module_id: *module_id,
+                };
+                let module_impl_blocks = db.impls_in_module(module);
+                (module, ImplBlock::from_id(module_impl_blocks, *impl_id))
+            })
+    }
+
     fn collect_recursive(&mut self, db: &impl HirDatabase, module: &Module) {
         let module_impl_blocks = db.impls_in_module(module.clone());
 
-        for (impl_id, impl_data) in module_impl_blocks.impls.iter() {
+        for (impl_id, _) in module_impl_blocks.impls.iter() {
             let impl_block = ImplBlock::from_id(Arc::clone(&module_impl_blocks), impl_id);
 
-            if let Some(_target_trait) = impl_data.target_trait() {
-                // ignore for now
-            } else {
-                // TODO provide generics of impl
-                let generics = GenericParams::default();
-                let target_ty = Ty::from_hir(
-                    db,
-                    &module,
-                    Some(&impl_block),
-                    &generics,
-                    impl_data.target_type(),
-                );
-                if let Some(target_ty_fp) = TyFingerprint::for_impl(&target_ty) {
-                    self.impls
-                        .entry(target_ty_fp)
-                        .or_insert_with(Vec::new)
-                        .push((module.module_id, impl_id));
-                }
+            let target_ty = impl_block.target_ty(db);
+
+            if let Some(target_ty_fp) = TyFingerprint::for_impl(&target_ty) {
+                self.impls
+                    .entry(target_ty_fp)
+                    .or_insert_with(Vec::new)
+                    .push((module.module_id, impl_id));
+            }
+
+            if let Some(tr) = impl_block.target_trait(db) {
+                self.impls_by_trait
+                    .entry(tr.id)
+                    .or_insert_with(Vec::new)
+                    .push((module.module_id, impl_id));
             }
         }
 
@@ -99,6 +115,7 @@ impl CrateImplBlocks {
         let mut crate_impl_blocks = CrateImplBlocks {
             krate: krate.clone(),
             impls: FxHashMap::default(),
+            impls_by_trait: FxHashMap::default(),
         };
         if let Some(module) = krate.root_module(db) {
             crate_impl_blocks.collect_recursive(db, &module);
diff --git a/crates/ra_hir/src/ty/snapshots/tests__infer_function_generics.snap b/crates/ra_hir/src/ty/snapshots/tests__infer_function_generics.snap
index 8ff6e55a6..91c48897c 100644
--- a/crates/ra_hir/src/ty/snapshots/tests__infer_function_generics.snap
+++ b/crates/ra_hir/src/ty/snapshots/tests__infer_function_generics.snap
@@ -1,12 +1,12 @@
 ---
-created: "2019-01-26T18:16:16.530712344+00:00"
+created: "2019-01-27T14:52:29.934503829+00:00"
 creator: [email protected]
 expression: "&result"
 source: crates/ra_hir/src/ty/tests.rs
 ---
-[10; 11) 't': [unknown]
-[21; 26) '{ t }': [unknown]
-[23; 24) 't': [unknown]
+[10; 11) 't': T
+[21; 26) '{ t }': T
+[23; 24) 't': T
 [38; 98) '{     ...(1); }': ()
 [44; 46) 'id': fn id<u32>(T) -> T
 [44; 52) 'id(1u32)': u32
diff --git a/crates/ra_hir/src/ty/snapshots/tests__infer_generic_chain.snap b/crates/ra_hir/src/ty/snapshots/tests__infer_generic_chain.snap
index f21bffa75..626f31252 100644
--- a/crates/ra_hir/src/ty/snapshots/tests__infer_generic_chain.snap
+++ b/crates/ra_hir/src/ty/snapshots/tests__infer_generic_chain.snap
@@ -1,5 +1,5 @@
 ---
-created: "2019-01-26T17:46:03.866825843+00:00"
+created: "2019-01-27T14:52:29.938713255+00:00"
 creator: [email protected]
 expression: "&result"
 source: crates/ra_hir/src/ty/tests.rs
@@ -8,9 +8,9 @@ source: crates/ra_hir/src/ty/tests.rs
 [65; 87) '{     ...     }': [unknown]
 [75; 79) 'self': A<[unknown]>
 [75; 81) 'self.x': [unknown]
-[99; 100) 't': [unknown]
-[110; 115) '{ t }': [unknown]
-[112; 113) 't': [unknown]
+[99; 100) 't': T
+[110; 115) '{ t }': T
+[112; 113) 't': T
 [135; 261) '{     ....x() }': i128
 [146; 147) 'x': i32
 [150; 151) '1': i32
diff --git a/crates/ra_hir/src/ty/snapshots/tests__infer_type_param.snap b/crates/ra_hir/src/ty/snapshots/tests__infer_type_param.snap
index a99323264..216d1e41f 100644
--- a/crates/ra_hir/src/ty/snapshots/tests__infer_type_param.snap
+++ b/crates/ra_hir/src/ty/snapshots/tests__infer_type_param.snap
@@ -1,15 +1,15 @@
 ---
-created: "2019-01-27T16:54:18.368427685+00:00"
+created: "2019-01-27T20:38:32.153717698+00:00"
 creator: [email protected]
 expression: "&result"
 source: crates/ra_hir/src/ty/tests.rs
 ---
-[10; 11) 'x': [unknown]
-[21; 30) '{     x }': [unknown]
-[27; 28) 'x': [unknown]
-[44; 45) 'x': &[unknown]
-[56; 65) '{     x }': &[unknown]
-[62; 63) 'x': &[unknown]
+[10; 11) 'x': T
+[21; 30) '{     x }': T
+[27; 28) 'x': T
+[44; 45) 'x': &T
+[56; 65) '{     x }': &T
+[62; 63) 'x': &T
 [77; 157) '{     ...(1); }': ()
 [87; 88) 'y': u32
 [91; 96) '10u32': u32