Issue 5652. Suggest to use effective integer division ~/, warning and Quick Fix.

compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java

Index: compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java
diff --git a/compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java b/compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java
index 28ebdb486e6366ebd4334f13acbc513117972c64..d198622ef75e976594156ed90c4f57cfb3283dee 100644
--- a/compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java
+++ b/compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java
@@ -1465,9 +1465,30 @@ public class TypeAnalyzer implements DartCompilationPhase {
       FunctionType methodType = getMethodType(receiver, member, name, nameNode);
       Type returnType = checkInvocation(node, nameNode, name, methodType);
       returnType = ExternalTypeAnalyzers.resolve(types, node, element, returnType);
+      warningEffectiveIntegerDivision(node, element);
       return returnType;
     }
 
+    /**
+     * http://code.google.com/p/dart/issues/detail?id=5652
+     */
+    private void warningEffectiveIntegerDivision(DartMethodInvocation node, Element element) {
+      if (element != null && element.getName().equals("toInt")
+          && element.getEnclosingElement() != null
+          && element.getEnclosingElement().getName().equals("num")) {
+        DartExpression target = node.getTarget();
+        while (target instanceof DartParenthesizedExpression) {
+          target = ((DartParenthesizedExpression) target).getExpression();
+        }
+        if (target instanceof DartBinaryExpression) {
+          DartBinaryExpression binary = (DartBinaryExpression) target;
+          if (binary.getOperator() == Token.DIV) {
+            typeError(node, TypeErrorCode.USE_INTEGER_DIVISION);
+          }
+        }
+      }
+    }
+
     private void checkIllegalPrivateAccess(DartNode diagnosticNode, Element element, String name) {
       if (DartIdentifier.isPrivateName(name)) {
         if (element != null) {