From 2745cb37c16600c99083cefdf5eb45a5205dd86d Mon Sep 17 00:00:00 2001
From: Florian Diebold <florian.diebold@freiheit.com>
Date: Fri, 19 Jun 2020 16:29:38 +0200
Subject: Use correct substs for super trait assoc types

When referring to an associated type of a super trait, we used the substs of the
subtrait. That led to the #4931 crash if the subtrait had less parameters, but
it could also lead to other incorrectness if just the order was different.

Fixes #4931.
---
 crates/ra_hir_ty/src/tests/regression.rs | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

(limited to 'crates/ra_hir_ty/src/tests/regression.rs')

diff --git a/crates/ra_hir_ty/src/tests/regression.rs b/crates/ra_hir_ty/src/tests/regression.rs
index ed43df484..8dc5603b7 100644
--- a/crates/ra_hir_ty/src/tests/regression.rs
+++ b/crates/ra_hir_ty/src/tests/regression.rs
@@ -665,3 +665,31 @@ impl Foo<i64> {
     "###
     );
 }
+
+#[test]
+fn issue_4931() {
+    assert_snapshot!(
+        infer(r#"
+trait Div<T> {
+    type Output;
+}
+
+trait CheckedDiv: Div<()> {}
+
+trait PrimInt: CheckedDiv<Output = ()> {
+    fn pow(self);
+}
+
+fn check<T: PrimInt>(i: T) {
+    i.pow();
+}
+"#),
+        @r###"
+    118..122 'self': Self
+    149..150 'i': T
+    155..171 '{     ...w(); }': ()
+    161..162 'i': T
+    161..168 'i.pow()': ()
+    "###
+    );
+}
-- 
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