3 files changed, 44 insertions, 5 deletions

diff --git a/crates/ra_hir/src/ty/infer.rs b/crates/ra_hir/src/ty/infer.rs
index 7ca1ff595..c7772a7f6 100644
--- a/crates/ra_hir/src/ty/infer.rs
+++ b/crates/ra_hir/src/ty/infer.rs
@@ -462,6 +462,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
         let remaining_index = remaining_index.unwrap_or(path.segments.len());
         let mut actual_def_ty: Option<Ty> = None;
 
+        let krate = resolver.krate()?;
         // resolve intermediate segments
         for (i, segment) in path.segments[remaining_index..].iter().enumerate() {
             let ty = match resolved {
@@ -500,9 +501,10 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
             // Attempt to find an impl_item for the type which has a name matching
             // the current segment
             log::debug!("looking for path segment: {:?}", segment);
+
             actual_def_ty = Some(ty.clone());
 
-            let item: crate::ModuleDef = ty.iterate_impl_items(self.db, |item| {
+            let item: crate::ModuleDef = ty.iterate_impl_items(self.db, krate, |item| {
                 let matching_def: Option<crate::ModuleDef> = match item {
                     crate::ImplItem::Method(func) => {
                         let sig = func.signature(self.db);
diff --git a/crates/ra_hir/src/ty/method_resolution.rs b/crates/ra_hir/src/ty/method_resolution.rs
index 667b66095..ea6e0dc0f 100644
--- a/crates/ra_hir/src/ty/method_resolution.rs
+++ b/crates/ra_hir/src/ty/method_resolution.rs
@@ -14,6 +14,7 @@ use crate::{
     resolve::Resolver,
     traits::TraitItem,
     generics::HasGenericParams,
+    ty::primitive::{UncertainIntTy, UncertainFloatTy}
 };
 use super::{TraitRef, Substs};
 
@@ -110,10 +111,19 @@ impl CrateImplBlocks {
     }
 }
 
-fn def_crate(db: &impl HirDatabase, ty: &Ty) -> Option<Crate> {
+fn def_crate(db: &impl HirDatabase, cur_crate: Crate, ty: &Ty) -> Option<Crate> {
     match ty {
         Ty::Apply(a_ty) => match a_ty.ctor {
             TypeCtor::Adt(def_id) => def_id.krate(db),
+            TypeCtor::Bool => db.lang_item(cur_crate, "bool".into())?.krate(db),
+            TypeCtor::Char => db.lang_item(cur_crate, "char".into())?.krate(db),
+            TypeCtor::Float(UncertainFloatTy::Known(f)) => {
+                db.lang_item(cur_crate, f.ty_to_string().into())?.krate(db)
+            }
+            TypeCtor::Int(UncertainIntTy::Known(i)) => {
+                db.lang_item(cur_crate, i.ty_to_string().into())?.krate(db)
+            }
+            TypeCtor::Str => db.lang_item(cur_crate, "str".into())?.krate(db),
             _ => None,
         },
         _ => None,
@@ -150,8 +160,11 @@ impl Ty {
         // find in the end takes &self, we still do the autoderef step (just as
         // rustc does an autoderef and then autoref again).
 
+        let krate = resolver.krate()?;
         for derefed_ty in self.autoderef(db) {
-            if let Some(result) = derefed_ty.iterate_inherent_methods(db, name, &mut callback) {
+            if let Some(result) =
+                derefed_ty.iterate_inherent_methods(db, name, krate, &mut callback)
+            {
                 return Some(result);
             }
             if let Some(result) =
@@ -208,9 +221,10 @@ impl Ty {
         &self,
         db: &impl HirDatabase,
         name: Option<&Name>,
+        krate: Crate,
         mut callback: impl FnMut(&Ty, Function) -> Option<T>,
     ) -> Option<T> {
-        let krate = match def_crate(db, self) {
+        let krate = match def_crate(db, krate, self) {
             Some(krate) => krate,
             None => return None,
         };
@@ -239,9 +253,10 @@ impl Ty {
     pub fn iterate_impl_items<T>(
         self,
         db: &impl HirDatabase,
+        krate: Crate,
         mut callback: impl FnMut(ImplItem) -> Option<T>,
     ) -> Option<T> {
-        let krate = def_crate(db, &self)?;
+        let krate = def_crate(db, krate, &self)?;
         let impls = db.impls_in_crate(krate);
 
         for impl_block in impls.lookup_impl_blocks(&self) {
diff --git a/crates/ra_hir/src/ty/tests.rs b/crates/ra_hir/src/ty/tests.rs
index 8d8a0eaaa..86f18b487 100644
--- a/crates/ra_hir/src/ty/tests.rs
+++ b/crates/ra_hir/src/ty/tests.rs
@@ -627,6 +627,28 @@ fn test(a: A) {
 }
 
 #[test]
+fn infer_inherent_method_str() {
+    assert_snapshot_matches!(
+        infer(r#"
+#[lang = "str"]
+impl str {
+    fn foo(&self) -> i32 {}
+}
+
+fn test() {
+    "foo".foo();
+}
+"#),
+        @r###"
+[40; 44) 'self': &str
+[53; 55) '{}': ()
+[69; 89) '{     ...o(); }': ()
+[75; 80) '"foo"': &str
+[75; 86) '"foo".foo()': i32"###
+    );
+}
+
+#[test]
 fn infer_tuple() {
     assert_snapshot_matches!(
         infer(r#"