redundant cast: don't warn if functional expression corresponds to another interface method (IDEA-140218)

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/redundantCast/AnotherInterfaceMethodIsPointed.java

@@ -0,0 +1,26 @@
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.List;
+import java.util.function.Consumer;
+
+interface IoFunction<T> extends Consumer<T> {
+  @Override
+  default void accept(T t) {}
+
+  void acceptX(T t) throws IOException;
+}
+
+interface IFunction<T> extends Consumer<T> {
+  void accept(T t);
+}
+
+interface IIFunction<T> extends Consumer<T> {}
+
+class Test {
+  public static void main(String[] args) {
+    List<String> strings = Arrays.asList("a", "b", "c");
+    strings.forEach((IoFunction<String>) arg -> {throw new IOException();});
+    strings.forEach((<warning descr="Casting 'arg -> {}' to 'IFunction<String>' is redundant">IFunction<String></warning>) arg -> {});
+    strings.forEach((<warning descr="Casting 'arg -> {}' to 'IIFunction<String>' is redundant">IIFunction<String></warning>) arg -> {});
+  }
+}