Start implementing checked mode compile time errors in analyzer.

editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/verifier/ErrorVerifier.java

Index: editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/verifier/ErrorVerifier.java
diff --git a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/verifier/ErrorVerifier.java b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/verifier/ErrorVerifier.java
index 2adc8e05b9a075050e35eb187922b984b68f8f09..6e144abda6e8467c7f6164c78454116a846bf409 100644
--- a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/verifier/ErrorVerifier.java
+++ b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/verifier/ErrorVerifier.java
@@ -99,6 +99,7 @@ import com.google.dart.engine.ast.WhileStatement;
 import com.google.dart.engine.ast.WithClause;
 import com.google.dart.engine.ast.YieldStatement;
 import com.google.dart.engine.ast.visitor.RecursiveAstVisitor;
+import com.google.dart.engine.context.AnalysisOptions;
 import com.google.dart.engine.element.ClassElement;
 import com.google.dart.engine.element.ConstructorElement;
 import com.google.dart.engine.element.Element;
@@ -420,6 +421,12 @@ public class ErrorVerifier extends RecursiveAstVisitor<Void> {
   private final InterfaceType[] DISALLOWED_TYPES_TO_EXTEND_OR_IMPLEMENT;
 
   /**
+   * A flag indicating whether we should generate errors when there are type errors in the
+   * evaluation of constants.
+   */
+  private boolean enableTypeChecks;
+
+  /**
    * Static final string with value {@code "getter "} used in the construction of the
    * {@link StaticWarningCode#NON_ABSTRACT_CLASS_INHERITS_ABSTRACT_MEMBER_ONE}, and similar, error
    * code messages.
@@ -448,6 +455,8 @@ public class ErrorVerifier extends RecursiveAstVisitor<Void> {
     this.hasExtUri = currentLibrary.hasExtUri();
     this.typeProvider = typeProvider;
     this.inheritanceManager = inheritanceManager;
+    AnalysisOptions options = currentLibrary.getContext().getAnalysisOptions();
+    this.enableTypeChecks = options.getEnableTypeChecks();
     isEnclosingConstructorConst = false;
     isInCatchClause = false;
     isInStaticVariableDeclaration = false;
@@ -3414,7 +3423,13 @@ public class ErrorVerifier extends RecursiveAstVisitor<Void> {
       return false;
     }
     // report problem
-    if (isEnclosingConstructorConst) {
+    if (isEnclosingConstructorConst && enableTypeChecks) {
+      // TODO(paulberry): this error should be based on the actual type of the constant, not the
+      // static type.  See dartbug.com/21119.
+      // TODO(paulberry): in the long run, we would prefer to implement this by having the analysis
+      // engine output a new type of error that means "error if run in checked mode", rather than
+      // having the analysis engine choose whether to issue the error based on whether checked mode
+      // is enabled.
       errorReporter.reportTypeErrorForNode(
           CompileTimeErrorCode.CONST_FIELD_INITIALIZER_NOT_ASSIGNABLE,
           expression,