2 files changed, 67 insertions, 0 deletions

diff --git a/crates/ra_hir_ty/src/tests/patterns.rs b/crates/ra_hir_ty/src/tests/patterns.rs
index 07cbc521a..6ea51d5d3 100644
--- a/crates/ra_hir_ty/src/tests/patterns.rs
+++ b/crates/ra_hir_ty/src/tests/patterns.rs
@@ -455,3 +455,29 @@ fn test() {
     "###
     );
 }
+
+#[test]
+fn infer_guard() {
+    assert_snapshot!(
+        infer(r#"
+struct S;
+impl S { fn foo(&self) -> bool { false } }
+
+fn main() {
+    match S {
+        s if s.foo() => (),
+    }
+}
+    "#), @"
+        [28; 32) 'self': &S
+        [42; 51) '{ false }': bool
+        [44; 49) 'false': bool
+        [65; 116) '{     ...   } }': ()
+        [71; 114) 'match ...     }': ()
+        [77; 78) 'S': S
+        [89; 90) 's': S
+        [94; 95) 's': S
+        [94; 101) 's.foo()': bool
+        [105; 107) '()': ()
+    ")
+}
diff --git a/crates/ra_hir_ty/src/tests/regression.rs b/crates/ra_hir_ty/src/tests/regression.rs
index 61284d672..61a6801fc 100644
--- a/crates/ra_hir_ty/src/tests/regression.rs
+++ b/crates/ra_hir_ty/src/tests/regression.rs
@@ -533,3 +533,44 @@ fn foo(b: Bar) {
     "###
     );
 }
+
+#[test]
+fn issue_4053_diesel_where_clauses() {
+    assert_snapshot!(
+        infer(r#"
+trait BoxedDsl<DB> {
+    type Output;
+    fn internal_into_boxed(self) -> Self::Output;
+}
+
+struct SelectStatement<From, Select, Distinct, Where, Order, LimitOffset, GroupBy, Locking> {
+    order: Order,
+}
+
+trait QueryFragment<DB: Backend> {}
+
+trait Into<T> { fn into(self) -> T; }
+
+impl<F, S, D, W, O, LOf, DB> BoxedDsl<DB>
+    for SelectStatement<F, S, D, W, O, LOf, G>
+where
+    O: Into<dyn QueryFragment<DB>>,
+{
+    type Output = XXX;
+
+    fn internal_into_boxed(self) -> Self::Output {
+        self.order.into();
+    }
+}
+"#),
+        @r###"
+    [66; 70) 'self': Self
+    [268; 272) 'self': Self
+    [467; 471) 'self': SelectStatement<F, S, D, W, O, LOf, {unknown}, {unknown}>
+    [489; 523) '{     ...     }': ()
+    [499; 503) 'self': SelectStatement<F, S, D, W, O, LOf, {unknown}, {unknown}>
+    [499; 509) 'self.order': O
+    [499; 516) 'self.o...into()': dyn QueryFragment<DB>
+    "###
+    );
+}