java redundant cast: forbid changing of substitutor if cast is removed (IDEA-184330)

this way neighbour functional expressions can't be broken

GitOrigin-RevId: c13823eca79157030f3dde53fa6a6d496be9c2b7

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

@@ -0,0 +1,58 @@
+import java.util.function.*;
+
+class A {
+  <T> void f(T a, Consumer<T> b) { }
+
+  void g(Object o) {
+    f((String) o, (t) -> t.charAt(0));
+  }
+}
+
+class Foo {
+
+  class Base { public int sub; }
+
+  class Sub1 extends Base { }
+
+  class Sub2 extends Base { }
+
+  public <T> void doSomething(T thing, BiConsumer<String, T> action) {
+    action.accept("HELLO", thing);
+  }
+
+  private Sub1 s1;
+  private Sub2 s2;
+
+  public void foo(Base base) {
+    if (base.sub == 1)
+      doSomething((Sub1) base, (s, b) -> { System.out.println(s); this.s1 = b; });
+    if (base.sub == 2)
+      doSomething((Sub2) base, (s, b) -> { System.out.println(s); this.s2 = b; });
+  }
+
+}
+
+class UnnecessaryCastError {
+
+  public static void main(String args[]) {
+    Env<String> env = new Env<>();
+
+    map((String) env.getArgument("to"), x -> parse(x));
+  }
+
+  public static <T, U> U map(T t, Function<T, U> mapper) {
+    return null;
+  }
+
+  public static String parse(String text) {
+    return null;
+  }
+
+  static class Env<T> {
+    <T> T getArgument(String s) {
+      return (<warning descr="Casting 'null' to 'T' is redundant">T</warning>) null;
+    }
+  }
+}
+
+