Add --no-declaration-casts option to analyzer.

pkg/analyzer/lib/src/generated/error_verifier.dart

Index: pkg/analyzer/lib/src/generated/error_verifier.dart
diff --git a/pkg/analyzer/lib/src/generated/error_verifier.dart b/pkg/analyzer/lib/src/generated/error_verifier.dart
index 0e15b058dcfbc56d01ba1aabaf5d835bf7730732..50513f74be7c9b4b34d9a864b80799d318001ad6 100644
--- a/pkg/analyzer/lib/src/generated/error_verifier.dart
+++ b/pkg/analyzer/lib/src/generated/error_verifier.dart
@@ -1205,7 +1205,8 @@ class ErrorVerifier extends RecursiveAstVisitor<Object> {
     SimpleIdentifier nameNode = node.name;
     Expression initializerNode = node.initializer;
     // do checks
-    _checkForInvalidAssignment(nameNode, initializerNode);
+    _checkForInvalidAssignment(nameNode, initializerNode,
+        isDeclarationCast: true);
     _checkForImplicitDynamicIdentifier(node, nameNode);
     // visit name
     nameNode.accept(this);
@@ -2504,20 +2505,24 @@ class ErrorVerifier extends RecursiveAstVisitor<Object> {
   }
 
   bool _checkForAssignableExpression(
-      Expression expression, DartType expectedStaticType, ErrorCode errorCode) {
+      Expression expression, DartType expectedStaticType, ErrorCode errorCode,
+      {bool isDeclarationCast = false}) {
     DartType actualStaticType = getStaticType(expression);
     return actualStaticType != null &&
         _checkForAssignableExpressionAtType(
-            expression, actualStaticType, expectedStaticType, errorCode);
+            expression, actualStaticType, expectedStaticType, errorCode,
+            isDeclarationCast: isDeclarationCast);
   }
 
   bool _checkForAssignableExpressionAtType(
       Expression expression,
       DartType actualStaticType,
       DartType expectedStaticType,
-      ErrorCode errorCode) {
+      ErrorCode errorCode,
+      {bool isDeclarationCast = false}) {
     if (!_expressionIsAssignableAtType(
-        expression, actualStaticType, expectedStaticType)) {
+        expression, actualStaticType, expectedStaticType,
+        isDeclarationCast: isDeclarationCast)) {
       _errorReporter.reportTypeErrorForNode(
           errorCode, expression, [actualStaticType, expectedStaticType]);
       return false;
@@ -4272,7 +4277,8 @@ class ErrorVerifier extends RecursiveAstVisitor<Object> {
           StaticTypeWarningCode.FOR_IN_OF_INVALID_TYPE,
           node.iterable,
           [iterableType, loopTypeName]);
-    } else if (!_typeSystem.isAssignableTo(bestIterableType, variableType)) {
+    } else if (!_typeSystem.isAssignableTo(bestIterableType, variableType,
+        isDeclarationCast: true)) {
       _errorReporter.reportTypeErrorForNode(
           StaticTypeWarningCode.FOR_IN_OF_INVALID_ELEMENT_TYPE,
           node.iterable,
@@ -4426,7 +4432,8 @@ class ErrorVerifier extends RecursiveAstVisitor<Object> {
    *
    * See [StaticTypeWarningCode.INVALID_ASSIGNMENT].
    */
-  void _checkForInvalidAssignment(Expression lhs, Expression rhs) {
+  void _checkForInvalidAssignment(Expression lhs, Expression rhs,
+      {bool isDeclarationCast = false}) {
     if (lhs == null || rhs == null) {
       return;
     }
@@ -4435,7 +4442,8 @@ class ErrorVerifier extends RecursiveAstVisitor<Object> {
         ? getStaticType(lhs)
         : leftVariableElement.type;
     _checkForAssignableExpression(
-        rhs, leftType, StaticTypeWarningCode.INVALID_ASSIGNMENT);
+        rhs, leftType, StaticTypeWarningCode.INVALID_ASSIGNMENT,
+        isDeclarationCast: isDeclarationCast);
   }
 
   /**
@@ -6318,13 +6326,15 @@ class ErrorVerifier extends RecursiveAstVisitor<Object> {
   }
 
   bool _expressionIsAssignableAtType(Expression expression,
-      DartType actualStaticType, DartType expectedStaticType) {
+      DartType actualStaticType, DartType expectedStaticType,
+      {isDeclarationCast: false}) {
     bool concrete = _options.strongMode && checker.hasStrictArrow(expression);
     if (concrete && actualStaticType is FunctionType) {
       actualStaticType =
           _typeSystem.functionTypeToConcreteType(actualStaticType);
     }
-    return _typeSystem.isAssignableTo(actualStaticType, expectedStaticType);
+    return _typeSystem.isAssignableTo(actualStaticType, expectedStaticType,
+        isDeclarationCast: isDeclarationCast);
   }
 
   MethodElement _findOverriddenMemberThatMustCallSuper(MethodDeclaration node) {