[ann] IDEA-69688 (unrestricted cast of return types of JSR-292 "polymorphic" methods)

java/java-impl/src/com/intellij/codeInsight/daemon/impl/analysis/HighlightUtil.java

@@ -17,6 +17,7 @@ package com.intellij.codeInsight.daemon.impl.analysis;
 
 import com.google.common.collect.Lists;
 import com.google.common.collect.Sets;
+import com.intellij.codeInsight.AnnotationUtil;
 import com.intellij.codeInsight.ExceptionUtil;
 import com.intellij.codeInsight.daemon.JavaErrorMessages;
 import com.intellij.codeInsight.daemon.impl.HighlightInfo;
@@ -337,16 +338,36 @@ public class HighlightUtil {
 
   @Nullable
   static HighlightInfo checkInconvertibleTypeCast(PsiTypeCastExpression expression) {
+    PsiTypeElement castTypeElement = expression.getCastType();
+    if (castTypeElement == null) return null;
+    PsiType castType = castTypeElement.getType();
+
     PsiExpression operand = expression.getOperand();
-    PsiType castType = expression.getCastType().getType();
-    PsiType operandType = operand == null ? null : operand.getType();
+    if (operand == null || isPolymorphicCall(operand)) return null;
+    PsiType operandType = operand.getType();
+
     if (operandType != null && !TypeConversionUtil.areTypesConvertible(operandType, castType)) {
       String message = JavaErrorMessages.message("inconvertible.type.cast", formatType(operandType), formatType(castType));
       return HighlightInfo.createHighlightInfo(HighlightInfoType.ERROR, expression, message);
     }
+
     return null;
   }
 
+  /**
+   * <a href="http://download.java.net/jdk7/docs/api/java/lang/invoke/MethodHandle.html#sigpoly">Signature polymorphism</a>
+   */
+  private static boolean isPolymorphicCall(final PsiExpression expression) {
+    if (PsiUtil.isLanguageLevel7OrHigher(expression) &&
+        expression instanceof PsiMethodCallExpression) {
+      final PsiElement method = ((PsiMethodCallExpression)expression).getMethodExpression().resolve();
+      if (method instanceof PsiMethod &&
+          AnnotationUtil.isAnnotated((PsiMethod)method, CommonClassNames.JAVA_LANG_INVOKE_MH_POLYMORPHIC, false, true)) {
+        return true;
+      }
+    }
+    return false;
+  }
 
   @Nullable
   static HighlightInfo checkVariableExpected(PsiExpression expression) {

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlighting7/PolymorphicTypeCast.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2000-2011 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodType;
+
+class C {
+  // from http://download.java.net/jdk7/docs/api/java/lang/invoke/MethodHandle.html, "Usage examples"
+  void m() throws Throwable {
+    Object x, y; String s; int i;
+    MethodType mt; MethodHandle mh;
+    MethodHandles.Lookup lookup = MethodHandles.lookup();
+
+// mt is (char,char)String
+    mt = MethodType.methodType(String.class, char.class, char.class);
+    mh = lookup.findVirtual(String.class, "replace", mt);
+    s = (String) mh.invokeExact("daddy",'d','n');
+
+// invokeExact(Ljava/lang/String;CC)Ljava/lang/String;
+    assert(s.equals("nanny"));
+
+// weakly typed invocation (using MHs.invoke)
+    s = (String) mh.invokeWithArguments("sappy", 'p', 'v');
+    assert(s.equals("savvy"));
+
+// mt is (Object[])List
+    mt = MethodType.methodType(java.util.List.class, Object[].class);
+    mh = lookup.findStatic(java.util.Arrays.class, "asList", mt);
+    assert(mh.isVarargsCollector());
+    x = mh.invokeGeneric("one", "two");
+
+// invokeGeneric(Ljava/lang/String;Ljava/lang/String;)Ljava/lang/Object;
+    assert(x.equals(java.util.Arrays.asList("one","two")));
+
+// mt is (Object,Object,Object)Object
+    mt = MethodType.genericMethodType(3);
+    mh = mh.asType(mt);
+    x = mh.invokeExact((Object)1, (Object)2, (Object)3);
+
+// invokeExact(Ljava/lang/Object;Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;
+    assert(x.equals(java.util.Arrays.asList(1,2,3)));
+
+// mt is int()
+    mt = MethodType.methodType(int.class);
+    mh = lookup.findVirtual(java.util.List.class, "size", mt);
+    i = (int) mh.invokeExact(java.util.Arrays.asList(1,2,3));
+
+// invokeExact(Ljava/util/List;)I
+    assert(i == 3);
+    mt = MethodType.methodType(void.class, String.class);
+    mh = lookup.findVirtual(java.io.PrintStream.class, "println", mt);
+    mh.invokeExact(System.out, "Hello, world.");
+// invokeExact(Ljava/io/PrintStream;Ljava/lang/String;)V
+  }
+
+  void unsupported() {
+    Object o = 42;
+    int i = <error descr="Inconvertible types; cannot cast 'java.lang.Object' to 'int'">(int) o</error>;
+    System.out.println(i);
+    m(<error descr="Inconvertible types; cannot cast 'java.lang.Object' to 'int'">(int) o</error>);
+    if (<error descr="Inconvertible types; cannot cast 'java.lang.Object' to 'int'">o instanceof int</error>) {
+      i = (Integer) o;
+      System.out.println(i);
+    }
+  }
+
+  void m(int i) { }
+}

java/java-tests/testSrc/com/intellij/codeInsight/daemon/LightAdvHighlightingJdk7Test.java

@@ -260,4 +260,9 @@ public class LightAdvHighlightingJdk7Test extends LightDaemonAnalyzerTestCase {
   public void testJavacQuirks() throws Exception {
     doTest(true, false);
   }
+
+  public void testPolymorphicTypeCast() throws Exception {
+    Object o = null;
+    doTest(false, false);
+  }
 }

java/openapi/src/com/intellij/psi/CommonClassNames.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2009 JetBrains s.r.o.
+ * Copyright 2000-2011 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -80,4 +80,6 @@ public interface CommonClassNames {
 
   @NonNls String JAVA_UTIL_CONCURRENT_FUTURE = "java.util.concurrent.Future";
   @NonNls String JAVA_UTIL_ARRAY_LIST = "java.util.ArrayList";
+
+  @NonNls String JAVA_LANG_INVOKE_MH_POLYMORPHIC = "java.lang.invoke.MethodHandle.PolymorphicSignature";
 }