method refs: propagate substitutor from method reference resolve to upper level inference (IDEA-91988)

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/methodRef/InferenceFromMethodReference.java

@@ -0,0 +1,21 @@
+class Test {
+    static <U> Iterable<U> map(Mapper<? super String, ? extends U> mapper) {
+        return null;
+    }
+
+    static void test() {
+        Integer next = map(String::length).iterator().next();
+        Integer next1 = map(Test::length).iterator().next();
+    }
+
+    public static <T> T length(T s) {
+      return null;
+    }
+
+    public static <T> int length(String s) {
+      return 0;
+    }
+}
+interface Mapper<T, U> {
+    U map(T t);
+}