diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index eb6fa4240a4..5a7c6fa29e5 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -7158,11 +7158,10 @@ namespace ts {
                             inferFromTypes(source, t);
                         }
                     }
-                    // Next, if target is a union type containing a single naked type parameter, make a
-                    // secondary inference to that type parameter. We don't do this for intersection types
-                    // because in a target type like Foo & T we don't know how which parts of the source type
-                    // should be matched by Foo and which should be inferred to T.
-                    if (target.flags & TypeFlags.Union && typeParameterCount === 1) {
+                    // Next, if target containings a single naked type parameter, make a secondary inference to that type
+                    // parameter. This gives meaningful results for union types in co-variant positions and intersection
+                    // types in contra-variant positions (such as callback parameters).
+                    if (typeParameterCount === 1) {
                         inferiority++;
                         inferFromTypes(source, typeParameter);
                         inferiority--;