Remove error message when compile time constants used in +,-,/,* expressions

compiler/java/com/google/dart/compiler/resolver/CompileTimeConstantAnalyzer.java

Index: compiler/java/com/google/dart/compiler/resolver/CompileTimeConstantAnalyzer.java
diff --git a/compiler/java/com/google/dart/compiler/resolver/CompileTimeConstantAnalyzer.java b/compiler/java/com/google/dart/compiler/resolver/CompileTimeConstantAnalyzer.java
index a57418f8dd9d9d0f54af561be7fbe69badd37f8c..bfe7a3b95ae7afc7fc1489e938762c231e17f13f 100644
--- a/compiler/java/com/google/dart/compiler/resolver/CompileTimeConstantAnalyzer.java
+++ b/compiler/java/com/google/dart/compiler/resolver/CompileTimeConstantAnalyzer.java
@@ -215,19 +215,22 @@ public class CompileTimeConstantAnalyzer {
 
         case ADD:
           if (lhsType.equals(stringType)) {
+            // TODO(zundel): remove this when + no longer acceptable as string concat operator
             if (checkString(rhs, rhsType)) {
               rememberInferredType(x, stringType);
             }
-          } else if (checkNumber(lhs, lhsType) && checkNumber(rhs, rhsType)) {
-            rememberInferredType(x, numType);
+          } else {
+            checkMathExpression(x, lhs, rhs, lhsType, rhsType);
           }
           break;
         case SUB:
         case MUL:
         case DIV:
+          checkMathExpression(x, lhs, rhs, lhsType, rhsType);
+          break;
         case MOD:
           if (checkNumber(lhs, lhsType) && checkNumber(rhs, rhsType)) {
-            rememberInferredType(x, numType);
+            rememberInferredType(x, intType);
           }
           break;
         case LT:
@@ -246,6 +249,23 @@ public class CompileTimeConstantAnalyzer {
       return null;
     }
 
+    private void checkMathExpression(DartBinaryExpression x,
+                                     DartExpression lhs, DartExpression rhs,
+                                     Type lhsType, Type rhsType) {
+      if (checkNumber(lhs, lhsType) && checkNumber(rhs, rhsType)) {
+        if (lhsType.equals(intType) && rhsType.equals(intType)) {
+          rememberInferredType(x, intType);
+        } else if (lhsType.equals(doubleType) && rhsType.equals(doubleType)) {
+          rememberInferredType(x, doubleType);
+        } else  if (lhsType.equals(doubleType) && rhsType.equals(intType) 
+            || lhsType.equals(intType) && rhsType.equals(doubleType)) {
+          rememberInferredType(x, doubleType);
+        } else {
+          rememberInferredType(x, numType);
+        }
+      }
+    }
+
     @Override
     public Void visitBooleanLiteral(DartBooleanLiteral x) {
       rememberInferredType(x, boolType);