7 files changed, 199 insertions, 43 deletions

diff --git a/crates/ra_hir_ty/src/display.rs b/crates/ra_hir_ty/src/display.rs
index dcca1bace..37def7c03 100644
--- a/crates/ra_hir_ty/src/display.rs
+++ b/crates/ra_hir_ty/src/display.rs
@@ -10,7 +10,7 @@ pub struct HirFormatter<'a, 'b, DB> {
     buf: String,
     curr_size: usize,
     max_size: Option<usize>,
-    should_display_default_types: bool,
+    omit_verbose_types: bool,
 }
 
 pub trait HirDisplay {
@@ -20,7 +20,7 @@ pub trait HirDisplay {
     where
         Self: Sized,
     {
-        HirDisplayWrapper(db, self, None, true)
+        HirDisplayWrapper(db, self, None, false)
     }
 
     fn display_truncated<'a, DB>(
@@ -31,7 +31,7 @@ pub trait HirDisplay {
     where
         Self: Sized,
     {
-        HirDisplayWrapper(db, self, max_size, false)
+        HirDisplayWrapper(db, self, max_size, true)
     }
 }
 
@@ -74,8 +74,8 @@ where
         }
     }
 
-    pub fn should_display_default_types(&self) -> bool {
-        self.should_display_default_types
+    pub fn omit_verbose_types(&self) -> bool {
+        self.omit_verbose_types
     }
 }
 
@@ -93,7 +93,7 @@ where
             buf: String::with_capacity(20),
             curr_size: 0,
             max_size: self.2,
-            should_display_default_types: self.3,
+            omit_verbose_types: self.3,
         })
     }
 }
diff --git a/crates/ra_hir_ty/src/infer.rs b/crates/ra_hir_ty/src/infer.rs
index e97b81473..32c0d07a5 100644
--- a/crates/ra_hir_ty/src/infer.rs
+++ b/crates/ra_hir_ty/src/infer.rs
@@ -37,8 +37,8 @@ use test_utils::tested_by;
 use super::{
     primitive::{FloatTy, IntTy},
     traits::{Guidance, Obligation, ProjectionPredicate, Solution},
-    ApplicationTy, InEnvironment, ProjectionTy, Substs, TraitEnvironment, TraitRef, Ty, TypeCtor,
-    TypeWalk, Uncertain,
+    ApplicationTy, GenericPredicate, InEnvironment, ProjectionTy, Substs, TraitEnvironment,
+    TraitRef, Ty, TypeCtor, TypeWalk, Uncertain,
 };
 use crate::{db::HirDatabase, infer::diagnostics::InferenceDiagnostic};
 
@@ -379,6 +379,25 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
     ) -> Ty {
         match assoc_ty {
             Some(res_assoc_ty) => {
+                // FIXME:
+                // Check if inner_ty is is `impl Trait` and contained input TypeAlias id
+                // this is a workaround while Chalk assoc type projection doesn't always work yet,
+                // but once that is fixed I don't think we should keep this
+                // (we'll probably change how associated types are resolved anyway)
+                if let Ty::Opaque(ref predicates) = inner_ty {
+                    for p in predicates.iter() {
+                        if let GenericPredicate::Projection(projection) = p {
+                            if projection.projection_ty.associated_ty == res_assoc_ty {
+                                if let ty_app!(_, params) = &projection.ty {
+                                    if params.len() == 0 {
+                                        return projection.ty.clone();
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+
                 let ty = self.table.new_type_var();
                 let builder = Substs::build_for_def(self.db, res_assoc_ty)
                     .push(inner_ty)
diff --git a/crates/ra_hir_ty/src/lib.rs b/crates/ra_hir_ty/src/lib.rs
index 48abf97c9..55b6dd836 100644
--- a/crates/ra_hir_ty/src/lib.rs
+++ b/crates/ra_hir_ty/src/lib.rs
@@ -821,6 +821,8 @@ impl TypeWalk for Ty {
     }
 }
 
+const TYPE_HINT_TRUNCATION: &str = "…";
+
 impl HirDisplay for &Ty {
     fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
         HirDisplay::hir_fmt(*self, f)
@@ -830,7 +832,7 @@ impl HirDisplay for &Ty {
 impl HirDisplay for ApplicationTy {
     fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
         if f.should_truncate() {
-            return write!(f, "…");
+            return write!(f, "{}", TYPE_HINT_TRUNCATION);
         }
 
         match self.ctor {
@@ -908,9 +910,7 @@ impl HirDisplay for ApplicationTy {
                     write!(f, "<")?;
 
                     let mut non_default_parameters = Vec::with_capacity(self.parameters.len());
-                    let parameters_to_write = if f.should_display_default_types() {
-                        self.parameters.0.as_ref()
-                    } else {
+                    let parameters_to_write = if f.omit_verbose_types() {
                         match self
                             .ctor
                             .as_generic_def()
@@ -935,6 +935,8 @@ impl HirDisplay for ApplicationTy {
                                 &non_default_parameters
                             }
                         }
+                    } else {
+                        self.parameters.0.as_ref()
                     };
 
                     f.write_joined(parameters_to_write, ", ")?;
@@ -959,9 +961,16 @@ impl HirDisplay for ApplicationTy {
                 let sig = self.parameters[0]
                     .callable_sig(f.db)
                     .expect("first closure parameter should contain signature");
-                write!(f, "|")?;
-                f.write_joined(sig.params(), ", ")?;
-                write!(f, "| -> {}", sig.ret().display(f.db))?;
+                let return_type_hint = sig.ret().display(f.db);
+                if sig.params().is_empty() {
+                    write!(f, "|| -> {}", return_type_hint)?;
+                } else if f.omit_verbose_types() {
+                    write!(f, "|{}| -> {}", TYPE_HINT_TRUNCATION, return_type_hint)?;
+                } else {
+                    write!(f, "|")?;
+                    f.write_joined(sig.params(), ", ")?;
+                    write!(f, "| -> {}", return_type_hint)?;
+                };
             }
         }
         Ok(())
@@ -971,7 +980,7 @@ impl HirDisplay for ApplicationTy {
 impl HirDisplay for ProjectionTy {
     fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
         if f.should_truncate() {
-            return write!(f, "…");
+            return write!(f, "{}", TYPE_HINT_TRUNCATION);
         }
 
         let trait_name = f.db.trait_data(self.trait_(f.db)).name.clone();
@@ -989,7 +998,7 @@ impl HirDisplay for ProjectionTy {
 impl HirDisplay for Ty {
     fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
         if f.should_truncate() {
-            return write!(f, "…");
+            return write!(f, "{}", TYPE_HINT_TRUNCATION);
         }
 
         match self {
@@ -1074,7 +1083,7 @@ impl HirDisplay for Ty {
 impl TraitRef {
     fn hir_fmt_ext(&self, f: &mut HirFormatter<impl HirDatabase>, use_as: bool) -> fmt::Result {
         if f.should_truncate() {
-            return write!(f, "…");
+            return write!(f, "{}", TYPE_HINT_TRUNCATION);
         }
 
         self.substs[0].hir_fmt(f)?;
@@ -1108,7 +1117,7 @@ impl HirDisplay for &GenericPredicate {
 impl HirDisplay for GenericPredicate {
     fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
         if f.should_truncate() {
-            return write!(f, "…");
+            return write!(f, "{}", TYPE_HINT_TRUNCATION);
         }
 
         match self {
diff --git a/crates/ra_hir_ty/src/tests.rs b/crates/ra_hir_ty/src/tests.rs
index d447b4571..d1f10e675 100644
--- a/crates/ra_hir_ty/src/tests.rs
+++ b/crates/ra_hir_ty/src/tests.rs
@@ -11,8 +11,8 @@ use std::fmt::Write;
 use std::sync::Arc;
 
 use hir_def::{
-    body::BodySourceMap, child_by_source::ChildBySource, db::DefDatabase, keys,
-    nameres::CrateDefMap, AssocItemId, DefWithBodyId, LocalModuleId, Lookup, ModuleDefId,
+    body::BodySourceMap, child_by_source::ChildBySource, db::DefDatabase, item_scope::ItemScope,
+    keys, nameres::CrateDefMap, AssocItemId, DefWithBodyId, LocalModuleId, Lookup, ModuleDefId,
 };
 use hir_expand::InFile;
 use insta::assert_snapshot;
@@ -163,35 +163,69 @@ fn visit_module(
     module_id: LocalModuleId,
     cb: &mut dyn FnMut(DefWithBodyId),
 ) {
-    for decl in crate_def_map[module_id].scope.declarations() {
-        match decl {
-            ModuleDefId::FunctionId(it) => cb(it.into()),
-            ModuleDefId::ConstId(it) => cb(it.into()),
-            ModuleDefId::StaticId(it) => cb(it.into()),
-            ModuleDefId::TraitId(it) => {
-                let trait_data = db.trait_data(it);
-                for &(_, item) in trait_data.items.iter() {
-                    match item {
-                        AssocItemId::FunctionId(it) => cb(it.into()),
-                        AssocItemId::ConstId(it) => cb(it.into()),
-                        AssocItemId::TypeAliasId(_) => (),
-                    }
-                }
-            }
-            ModuleDefId::ModuleId(it) => visit_module(db, crate_def_map, it.local_id, cb),
-            _ => (),
-        }
-    }
+    visit_scope(db, crate_def_map, &crate_def_map[module_id].scope, cb);
     for impl_id in crate_def_map[module_id].scope.impls() {
         let impl_data = db.impl_data(impl_id);
         for &item in impl_data.items.iter() {
             match item {
-                AssocItemId::FunctionId(it) => cb(it.into()),
-                AssocItemId::ConstId(it) => cb(it.into()),
+                AssocItemId::FunctionId(it) => {
+                    let def = it.into();
+                    cb(def);
+                    let body = db.body(def);
+                    visit_scope(db, crate_def_map, &body.item_scope, cb);
+                }
+                AssocItemId::ConstId(it) => {
+                    let def = it.into();
+                    cb(def);
+                    let body = db.body(def);
+                    visit_scope(db, crate_def_map, &body.item_scope, cb);
+                }
                 AssocItemId::TypeAliasId(_) => (),
             }
         }
     }
+
+    fn visit_scope(
+        db: &TestDB,
+        crate_def_map: &CrateDefMap,
+        scope: &ItemScope,
+        cb: &mut dyn FnMut(DefWithBodyId),
+    ) {
+        for decl in scope.declarations() {
+            match decl {
+                ModuleDefId::FunctionId(it) => {
+                    let def = it.into();
+                    cb(def);
+                    let body = db.body(def);
+                    visit_scope(db, crate_def_map, &body.item_scope, cb);
+                }
+                ModuleDefId::ConstId(it) => {
+                    let def = it.into();
+                    cb(def);
+                    let body = db.body(def);
+                    visit_scope(db, crate_def_map, &body.item_scope, cb);
+                }
+                ModuleDefId::StaticId(it) => {
+                    let def = it.into();
+                    cb(def);
+                    let body = db.body(def);
+                    visit_scope(db, crate_def_map, &body.item_scope, cb);
+                }
+                ModuleDefId::TraitId(it) => {
+                    let trait_data = db.trait_data(it);
+                    for &(_, item) in trait_data.items.iter() {
+                        match item {
+                            AssocItemId::FunctionId(it) => cb(it.into()),
+                            AssocItemId::ConstId(it) => cb(it.into()),
+                            AssocItemId::TypeAliasId(_) => (),
+                        }
+                    }
+                }
+                ModuleDefId::ModuleId(it) => visit_module(db, crate_def_map, it.local_id, cb),
+                _ => (),
+            }
+        }
+    }
 }
 
 fn ellipsize(mut text: String, max_len: usize) -> String {
diff --git a/crates/ra_hir_ty/src/tests/regression.rs b/crates/ra_hir_ty/src/tests/regression.rs
index 09d684ac2..8b3aa8564 100644
--- a/crates/ra_hir_ty/src/tests/regression.rs
+++ b/crates/ra_hir_ty/src/tests/regression.rs
@@ -1,7 +1,8 @@
-use super::infer;
 use insta::assert_snapshot;
 use test_utils::covers;
 
+use super::infer;
+
 #[test]
 fn bug_484() {
     assert_snapshot!(
@@ -331,3 +332,36 @@ pub fn main_loop() {
     "###
     );
 }
+
+#[test]
+fn issue_2669() {
+    assert_snapshot!(
+        infer(
+            r#"trait A {}
+    trait Write {}
+    struct Response<T> {}
+
+    trait D {
+        fn foo();
+    }
+
+    impl<T:A> D for Response<T> {
+        fn foo() {
+            end();
+            fn end<W: Write>() {
+                let _x: T =  loop {};
+            }
+        }
+    }"#
+        ),
+        @r###"
+    [147; 262) '{     ...     }': ()
+    [161; 164) 'end': fn end<{unknown}>() -> ()
+    [161; 166) 'end()': ()
+    [199; 252) '{     ...     }': ()
+    [221; 223) '_x': !
+    [230; 237) 'loop {}': !
+    [235; 237) '{}': ()
+    "###
+    )
+}
diff --git a/crates/ra_hir_ty/src/tests/simple.rs b/crates/ra_hir_ty/src/tests/simple.rs
index 3e5e163e3..00134c99b 100644
--- a/crates/ra_hir_ty/src/tests/simple.rs
+++ b/crates/ra_hir_ty/src/tests/simple.rs
@@ -1518,6 +1518,7 @@ fn test() {
     [167; 179) 'GLOBAL_CONST': u32
     [189; 191) 'id': u32
     [194; 210) 'Foo::A..._CONST': u32
+    [126; 128) '99': u32
     "###
     );
 }
@@ -1549,6 +1550,8 @@ fn test() {
     [233; 246) 'GLOBAL_STATIC': u32
     [256; 257) 'w': u32
     [260; 277) 'GLOBAL...IC_MUT': u32
+    [118; 120) '99': u32
+    [161; 163) '99': u32
     "###
     );
 }
diff --git a/crates/ra_hir_ty/src/tests/traits.rs b/crates/ra_hir_ty/src/tests/traits.rs
index ae316922b..0bc72644a 100644
--- a/crates/ra_hir_ty/src/tests/traits.rs
+++ b/crates/ra_hir_ty/src/tests/traits.rs
@@ -38,6 +38,63 @@ mod future {
 }
 
 #[test]
+fn infer_async() {
+    let (db, pos) = TestDB::with_position(
+        r#"
+//- /main.rs crate:main deps:std
+
+async fn foo() -> u64 {
+    128
+}
+
+fn test() {
+    let r = foo();
+    let v = r.await;
+    v<|>;
+}
+
+//- /std.rs crate:std
+#[prelude_import] use future::*;
+mod future {
+    trait Future {
+        type Output;
+    }
+}
+
+"#,
+    );
+    assert_eq!("u64", type_at_pos(&db, pos));
+}
+
+#[test]
+fn infer_desugar_async() {
+    let (db, pos) = TestDB::with_position(
+        r#"
+//- /main.rs crate:main deps:std
+
+async fn foo() -> u64 {
+    128
+}
+
+fn test() {
+    let r = foo();
+    r<|>;
+}
+
+//- /std.rs crate:std
+#[prelude_import] use future::*;
+mod future {
+    trait Future {
+        type Output;
+    }
+}
+
+"#,
+    );
+    assert_eq!("impl Future<Output = u64>", type_at_pos(&db, pos));
+}
+
+#[test]
 fn infer_try() {
     let (db, pos) = TestDB::with_position(
         r#"