5 files changed, 82 insertions, 89 deletions

diff --git a/crates/ra_hir/src/code_model.rs b/crates/ra_hir/src/code_model.rs
index a177cebca..346118350 100644
--- a/crates/ra_hir/src/code_model.rs
+++ b/crates/ra_hir/src/code_model.rs
@@ -21,8 +21,8 @@ use hir_expand::{
     MacroDefId,
 };
 use hir_ty::{
-    autoderef, display::HirFormatter, expr::ExprValidator, ApplicationTy, Canonical, InEnvironment,
-    TraitEnvironment, Ty, TyDefId, TypeCtor, TypeWalk,
+    autoderef, display::HirFormatter, expr::ExprValidator, method_resolution::implements_trait,
+    ApplicationTy, Canonical, InEnvironment, TraitEnvironment, Ty, TyDefId, TypeCtor, TypeWalk,
 };
 use ra_db::{CrateId, Edition, FileId};
 use ra_prof::profile;
@@ -878,6 +878,22 @@ impl Type {
         }
     }
 
+    /// Checks that particular type `ty` implements `std::future::Future`.
+    /// This function is used in `.await` syntax completion.
+    pub fn impls_future(&self, db: &impl HirDatabase) -> bool {
+        let krate = self.krate;
+
+        let std_future_trait =
+            db.lang_item(krate, "future_trait".into()).and_then(|it| it.as_trait());
+        let std_future_trait = match std_future_trait {
+            Some(it) => it,
+            None => return false,
+        };
+
+        let canonical_ty = Canonical { value: self.ty.value.clone(), num_vars: 0 };
+        implements_trait(&canonical_ty, db, self.ty.environment.clone(), krate, std_future_trait)
+    }
+
     // FIXME: this method is broken, as it doesn't take closures into account.
     pub fn as_callable(&self) -> Option<CallableDef> {
         Some(self.ty.value.as_callable()?.0)
diff --git a/crates/ra_hir/src/lib.rs b/crates/ra_hir/src/lib.rs
index 3d13978d4..a1cf89010 100644
--- a/crates/ra_hir/src/lib.rs
+++ b/crates/ra_hir/src/lib.rs
@@ -27,7 +27,7 @@ macro_rules! impl_froms {
 }
 
 pub mod db;
-pub mod source_binder;
+pub mod source_analyzer;
 
 pub mod diagnostics;
 
@@ -46,7 +46,7 @@ pub use crate::{
     },
     from_source::FromSource,
     has_source::HasSource,
-    source_binder::{PathResolution, ScopeEntryWithSyntax, SourceAnalyzer},
+    source_analyzer::{PathResolution, ScopeEntryWithSyntax, SourceAnalyzer},
 };
 
 pub use hir_def::{
diff --git a/crates/ra_hir/src/source_binder.rs b/crates/ra_hir/src/source_analyzer.rs
index a2a9d968c..3df48842d 100644
--- a/crates/ra_hir/src/source_binder.rs
+++ b/crates/ra_hir/src/source_analyzer.rs
@@ -15,17 +15,13 @@ use hir_def::{
     },
     expr::{ExprId, PatId},
     nameres::ModuleSource,
-    path::path,
     resolver::{self, resolver_for_scope, HasResolver, Resolver, TypeNs, ValueNs},
     AssocItemId, DefWithBodyId,
 };
 use hir_expand::{
     hygiene::Hygiene, name::AsName, AstId, HirFileId, InFile, MacroCallId, MacroCallKind,
 };
-use hir_ty::{
-    method_resolution::{self, implements_trait},
-    Canonical, InEnvironment, InferenceResult, TraitEnvironment, Ty,
-};
+use hir_ty::{method_resolution, Canonical, InEnvironment, InferenceResult, TraitEnvironment, Ty};
 use ra_prof::profile;
 use ra_syntax::{
     ast::{self, AstNode},
@@ -40,64 +36,6 @@ use crate::{
     TypeParam,
 };
 
-fn try_get_resolver_for_node(db: &impl HirDatabase, node: InFile<&SyntaxNode>) -> Option<Resolver> {
-    match_ast! {
-        match (node.value) {
-            ast::Module(it) => {
-                let src = node.with_value(it);
-                Some(crate::Module::from_declaration(db, src)?.id.resolver(db))
-            },
-             ast::SourceFile(it) => {
-                let src = node.with_value(ModuleSource::SourceFile(it));
-                Some(crate::Module::from_definition(db, src)?.id.resolver(db))
-            },
-            ast::StructDef(it) => {
-                let src = node.with_value(it);
-                Some(Struct::from_source(db, src)?.id.resolver(db))
-            },
-            ast::EnumDef(it) => {
-                let src = node.with_value(it);
-                Some(Enum::from_source(db, src)?.id.resolver(db))
-            },
-            ast::ImplBlock(it) => {
-                let src = node.with_value(it);
-                Some(ImplBlock::from_source(db, src)?.id.resolver(db))
-            },
-            ast::TraitDef(it) => {
-                let src = node.with_value(it);
-                Some(Trait::from_source(db, src)?.id.resolver(db))
-            },
-            _ => match node.value.kind() {
-                FN_DEF | CONST_DEF | STATIC_DEF => {
-                    let def = def_with_body_from_child_node(db, node)?;
-                    let def = DefWithBodyId::from(def);
-                    Some(def.resolver(db))
-                }
-                // FIXME add missing cases
-                _ => None
-            }
-        }
-    }
-}
-
-fn def_with_body_from_child_node(
-    db: &impl HirDatabase,
-    child: InFile<&SyntaxNode>,
-) -> Option<DefWithBody> {
-    let _p = profile("def_with_body_from_child_node");
-    child.cloned().ancestors_with_macros(db).find_map(|node| {
-        let n = &node.value;
-        match_ast! {
-            match n {
-                ast::FnDef(def)  => { return Function::from_source(db, node.with_value(def)).map(DefWithBody::from); },
-                ast::ConstDef(def) => { return Const::from_source(db, node.with_value(def)).map(DefWithBody::from); },
-                ast::StaticDef(def) => { return Static::from_source(db, node.with_value(def)).map(DefWithBody::from); },
-                _ => { None },
-            }
-        }
-    })
-}
-
 /// `SourceAnalyzer` is a convenience wrapper which exposes HIR API in terms of
 /// original source files. It should not be used inside the HIR itself.
 #[derive(Debug)]
@@ -454,25 +392,6 @@ impl SourceAnalyzer {
         )
     }
 
-    /// Checks that particular type `ty` implements `std::future::Future`.
-    /// This function is used in `.await` syntax completion.
-    pub fn impls_future(&self, db: &impl HirDatabase, ty: Type) -> bool {
-        let std_future_path = path![std::future::Future];
-
-        let std_future_trait = match self.resolver.resolve_known_trait(db, &std_future_path) {
-            Some(it) => it.into(),
-            _ => return false,
-        };
-
-        let krate = match self.resolver.krate() {
-            Some(krate) => krate,
-            _ => return false,
-        };
-
-        let canonical_ty = Canonical { value: ty.ty.value, num_vars: 0 };
-        implements_trait(&canonical_ty, db, &self.resolver, krate.into(), std_future_trait)
-    }
-
     pub fn expand(
         &self,
         db: &impl HirDatabase,
@@ -487,6 +406,64 @@ impl SourceAnalyzer {
     }
 }
 
+fn try_get_resolver_for_node(db: &impl HirDatabase, node: InFile<&SyntaxNode>) -> Option<Resolver> {
+    match_ast! {
+        match (node.value) {
+            ast::Module(it) => {
+                let src = node.with_value(it);
+                Some(crate::Module::from_declaration(db, src)?.id.resolver(db))
+            },
+             ast::SourceFile(it) => {
+                let src = node.with_value(ModuleSource::SourceFile(it));
+                Some(crate::Module::from_definition(db, src)?.id.resolver(db))
+            },
+            ast::StructDef(it) => {
+                let src = node.with_value(it);
+                Some(Struct::from_source(db, src)?.id.resolver(db))
+            },
+            ast::EnumDef(it) => {
+                let src = node.with_value(it);
+                Some(Enum::from_source(db, src)?.id.resolver(db))
+            },
+            ast::ImplBlock(it) => {
+                let src = node.with_value(it);
+                Some(ImplBlock::from_source(db, src)?.id.resolver(db))
+            },
+            ast::TraitDef(it) => {
+                let src = node.with_value(it);
+                Some(Trait::from_source(db, src)?.id.resolver(db))
+            },
+            _ => match node.value.kind() {
+                FN_DEF | CONST_DEF | STATIC_DEF => {
+                    let def = def_with_body_from_child_node(db, node)?;
+                    let def = DefWithBodyId::from(def);
+                    Some(def.resolver(db))
+                }
+                // FIXME add missing cases
+                _ => None
+            }
+        }
+    }
+}
+
+fn def_with_body_from_child_node(
+    db: &impl HirDatabase,
+    child: InFile<&SyntaxNode>,
+) -> Option<DefWithBody> {
+    let _p = profile("def_with_body_from_child_node");
+    child.cloned().ancestors_with_macros(db).find_map(|node| {
+        let n = &node.value;
+        match_ast! {
+            match n {
+                ast::FnDef(def)  => { return Function::from_source(db, node.with_value(def)).map(DefWithBody::from); },
+                ast::ConstDef(def) => { return Const::from_source(db, node.with_value(def)).map(DefWithBody::from); },
+                ast::StaticDef(def) => { return Static::from_source(db, node.with_value(def)).map(DefWithBody::from); },
+                _ => { None },
+            }
+        }
+    })
+}
+
 fn scope_for(
     scopes: &ExprScopes,
     source_map: &BodySourceMap,
diff --git a/crates/ra_hir_ty/src/method_resolution.rs b/crates/ra_hir_ty/src/method_resolution.rs
index 888dc3116..55435e6ea 100644
--- a/crates/ra_hir_ty/src/method_resolution.rs
+++ b/crates/ra_hir_ty/src/method_resolution.rs
@@ -465,7 +465,7 @@ fn transform_receiver_ty(
 pub fn implements_trait(
     ty: &Canonical<Ty>,
     db: &impl HirDatabase,
-    resolver: &Resolver,
+    env: Arc<TraitEnvironment>,
     krate: CrateId,
     trait_: TraitId,
 ) -> bool {
@@ -474,7 +474,6 @@ pub fn implements_trait(
         // anyway, but currently Chalk doesn't implement `dyn/impl Trait` yet
         return true;
     }
-    let env = TraitEnvironment::lower(db, resolver);
     let goal = generic_implements_goal(db, env, trait_, ty.clone());
     let solution = db.trait_solve(krate.into(), goal);
 
diff --git a/crates/ra_ide/src/completion/complete_dot.rs b/crates/ra_ide/src/completion/complete_dot.rs
index 210a685e4..9ab43644e 100644
--- a/crates/ra_ide/src/completion/complete_dot.rs
+++ b/crates/ra_ide/src/completion/complete_dot.rs
@@ -27,7 +27,7 @@ pub(super) fn complete_dot(acc: &mut Completions, ctx: &CompletionContext) {
     complete_methods(acc, ctx, &receiver_ty);
 
     // Suggest .await syntax for types that implement Future trait
-    if ctx.analyzer.impls_future(ctx.db, receiver_ty) {
+    if receiver_ty.impls_future(ctx.db) {
         CompletionItem::new(CompletionKind::Keyword, ctx.source_range(), "await")
             .detail("expr.await")
             .insert_text("await")
@@ -525,6 +525,7 @@ mod tests {
 
             //- /std/lib.rs
             pub mod future {
+                #[lang = "future_trait"]
                 pub trait Future {}
             }
             "###, CompletionKind::Keyword),