Adds more specific type binding information to MethodInvocation nodes…

…. The specific type of the expression may differ from the return type of its method binding. This helps CastResolver omit cast checks on arrays in some cases.

	Change on 2015/11/20 by kstanger <kstanger@google.com>
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=108337719

translator/src/main/java/com/google/devtools/j2objc/ast/MethodInvocation.java

@@ -27,13 +27,16 @@
 public class MethodInvocation extends Expression {
 
   private IMethodBinding methodBinding = null;
+  // The context-specific known type of this expression.
+  private ITypeBinding typeBinding = null;
   private ChildLink<Expression> expression = ChildLink.create(Expression.class, this);
   private ChildLink<SimpleName> name = ChildLink.create(SimpleName.class, this);
   private ChildList<Expression> arguments = ChildList.create(Expression.class, this);
 
   public MethodInvocation(org.eclipse.jdt.core.dom.MethodInvocation jdtNode) {
     super(jdtNode);
     methodBinding = jdtNode.resolveMethodBinding();
+    typeBinding = jdtNode.resolveTypeBinding();
     expression.set((Expression) TreeConverter.convert(jdtNode.getExpression()));
     name.set((SimpleName) TreeConverter.convert(jdtNode.getName()));
     for (Object argument : jdtNode.arguments()) {
@@ -44,17 +47,23 @@ public MethodInvocation(org.eclipse.jdt.core.dom.MethodInvocation jdtNode) {
   public MethodInvocation(MethodInvocation other) {
     super(other);
     methodBinding = other.getMethodBinding();
+    typeBinding = other.getTypeBinding();
     expression.copyFrom(other.getExpression());
     name.copyFrom(other.getName());
     arguments.copyFrom(other.getArguments());
   }
 
-  public MethodInvocation(IMethodBinding binding, Expression expression) {
+  public MethodInvocation(IMethodBinding binding, ITypeBinding typeBinding, Expression expression) {
     methodBinding = binding;
+    this.typeBinding = typeBinding;
     this.expression.set(expression);
     name.set(new SimpleName(binding));
   }
 
+  public MethodInvocation(IMethodBinding binding, Expression expression) {
+    this(binding, binding.getReturnType(), expression);
+  }
+
   @Override
   public Kind getKind() {
     return Kind.METHOD_INVOCATION;
@@ -70,7 +79,11 @@ public void setMethodBinding(IMethodBinding newMethodBinding) {
 
   @Override
   public ITypeBinding getTypeBinding() {
-    return methodBinding != null ? methodBinding.getReturnType() : null;
+    return typeBinding;
+  }
+
+  public void setTypeBinding(ITypeBinding newTypeBinding) {
+    typeBinding = newTypeBinding;
   }
 
   public Expression getExpression() {

translator/src/main/java/com/google/devtools/j2objc/translate/ArrayRewriter.java

@@ -86,7 +86,7 @@ private MethodInvocation newInitializedArrayInvocation(
       methodBinding.addParameter(typeEnv.getIOSClass());
     }
     MethodInvocation invocation =
-        new MethodInvocation(methodBinding, new SimpleName(iosArrayBinding));
+        new MethodInvocation(methodBinding, arrayType, new SimpleName(iosArrayBinding));
 
     // Create the array initializer and add it as the first parameter.
     ArrayInitializer arrayInit = new ArrayInitializer(arrayType);
@@ -150,7 +150,7 @@ private MethodInvocation newSingleDimensionArrayInvocation(
       methodBinding.addParameter(typeEnv.getIOSClass());
     }
     MethodInvocation invocation =
-        new MethodInvocation(methodBinding, new SimpleName(iosArrayBinding));
+        new MethodInvocation(methodBinding, arrayType, new SimpleName(iosArrayBinding));
 
     // Add the array length argument.
     invocation.getArguments().add(dimensionExpr.copy());
@@ -164,8 +164,9 @@ private MethodInvocation newSingleDimensionArrayInvocation(
   }
 
   private MethodInvocation newMultiDimensionArrayInvocation(
-      ITypeBinding componentType, List<Expression> dimensions, boolean retainedResult) {
+      ITypeBinding arrayType, List<Expression> dimensions, boolean retainedResult) {
     assert dimensions.size() > 1;
+    ITypeBinding componentType = arrayType;
     for (int i = 0; i < dimensions.size(); i++) {
       componentType = componentType.getComponentType();
     }
@@ -174,7 +175,7 @@ private MethodInvocation newMultiDimensionArrayInvocation(
     IOSMethodBinding methodBinding = getMultiDimensionMethod(
         componentType, iosArrayBinding, retainedResult);
     MethodInvocation invocation =
-        new MethodInvocation(methodBinding, new SimpleName(iosArrayBinding));
+        new MethodInvocation(methodBinding, arrayType, new SimpleName(iosArrayBinding));
 
     // Add the dimension count argument.
     invocation.getArguments().add(NumberLiteral.newIntLiteral(dimensions.size(), typeEnv));
@@ -195,12 +196,12 @@ private MethodInvocation newMultiDimensionArrayInvocation(
   }
 
   private IOSMethodBinding getMultiDimensionMethod(
-      ITypeBinding componentType, IOSTypeBinding arrayType, boolean retainedResult) {
+      ITypeBinding componentType, IOSTypeBinding iosArrayType, boolean retainedResult) {
     String selector = (retainedResult ? "newArray" : "array") + "WithDimensions:lengths:"
         + (componentType.isPrimitive() ? "" : "type:");
     IOSMethodBinding binding = IOSMethodBinding.newMethod(
         selector, Modifier.PUBLIC | Modifier.STATIC, typeEnv.resolveIOSType("IOSObjectArray"),
-        arrayType);
+        iosArrayType);
     ITypeBinding intType = typeEnv.resolveJavaType("int");
     binding.addParameter(intType);
     binding.addParameter(GeneratedTypeBinding.newArrayType(intType));

translator/src/main/java/com/google/devtools/j2objc/translate/CastResolver.java

@@ -165,7 +165,7 @@ private boolean needsCast(Expression expr, ITypeBinding expectedType, boolean sh
         // In most cases we don't need to cast from an id type. However, if the
         // expression is being dereferenced then the compiler needs the type
         // info.
-        || (declaredType == typeEnv.getIdType() && !shouldCastFromId)
+        || (typeEnv.isIdType(declaredType) && !shouldCastFromId)
         // If the declared type can be assigned into the actual type, or the
         // expected type, then the compiler already has sufficient type info.
         || typeEnv.isIdType(exprType) || typeEnv.isIdType(expectedType)

translator/src/test/java/com/google/devtools/j2objc/translate/CastResolverTest.java

@@ -222,8 +222,11 @@ public void testInterfaceComparisons() throws IOException {
 
   public void testGenericArrayCast() throws IOException {
     String translation = translateSourceFile(
-        "class Test<E> { E[] test(Object[] o) { return (E[])o; } }", "Test", "Test.m");
-    // No need to check the cast because the erasure of E[] is Object[].
+        "class Test<E> { E[] test(Object[] o) { E[] e = (E[]) new Object[0]; return (E[])o; } }",
+        "Test", "Test.m");
+    // No need to check either cast because the erasure of E[] is Object[].
+    assertTranslation(translation,
+        "IOSObjectArray *e = [IOSObjectArray arrayWithLength:0 type:NSObject_class_()];");
     assertTranslation(translation, "return o;");
     translation = translateSourceFile(
         "class Test<E extends String> { E[] test(Object[] o) { return (E[])o; } }",