fix #26141, add support for type arguments to constants

pkg/analyzer/lib/src/dart/constant/evaluation.dart

Index: pkg/analyzer/lib/src/dart/constant/evaluation.dart
diff --git a/pkg/analyzer/lib/src/dart/constant/evaluation.dart b/pkg/analyzer/lib/src/dart/constant/evaluation.dart
index 57eee8973823954d54ef94305c1c0136612c826c..fcc14e114871f6141ba89614b895a02ca94c587a 100644
--- a/pkg/analyzer/lib/src/dart/constant/evaluation.dart
+++ b/pkg/analyzer/lib/src/dart/constant/evaluation.dart
@@ -75,6 +75,9 @@ class ConstantEvaluationEngine {
    */
   final ConstantEvaluationValidator validator;
 
+  /** Whether we are running in strong mode. */
+  final bool strongMode;
+
   /**
    * Initialize a newly created [ConstantEvaluationEngine].  The [typeProvider]
    * is used to access known types.  [_declaredVariables] is the set of
@@ -82,9 +85,12 @@ class ConstantEvaluationEngine {
    * given, is used to verify correct dependency analysis when running unit
    * tests.
    */
-  ConstantEvaluationEngine(this.typeProvider, this._declaredVariables,
+  ConstantEvaluationEngine(TypeProvider typeProvider, this._declaredVariables,
       {ConstantEvaluationValidator validator, TypeSystem typeSystem})
-      : validator =
+      : typeProvider = typeProvider,
+        strongMode =
+            typeProvider.objectType.element.context.analysisOptions.strongMode,
+        validator =
             validator ?? new ConstantEvaluationValidator_ForProduction(),
         typeSystem = typeSystem ?? new TypeSystemImpl();
 
@@ -231,6 +237,7 @@ class ConstantEvaluationEngine {
             new ConstantVisitor(this, errorReporter);
         DartObjectImpl result = evaluateConstructorCall(
             constNode,
+            [],
             constNode.arguments.arguments,
             element,
             constantVisitor,
@@ -409,7 +416,8 @@ class ConstantEvaluationEngine {
 
   DartObjectImpl evaluateConstructorCall(
       AstNode node,
-      NodeList<Expression> arguments,
+      List<DartType> typeArguments,
+      List<Expression> arguments,
       ConstructorElement constructor,
       ConstantVisitor constantVisitor,
       ErrorReporter errorReporter) {
@@ -515,25 +523,41 @@ class ConstantEvaluationEngine {
       // so consider it an unknown value to suppress further errors.
       return new DartObjectImpl.validWithUnknownValue(definingClass);
     }
-    HashMap<String, DartObjectImpl> fieldMap =
-        new HashMap<String, DartObjectImpl>();
+    var fieldMap = new HashMap<String, DartObjectImpl>();
+    var typeArgumentMap = new HashMap<String, DartObjectImpl>.fromIterables(
+        (constructor.returnType as ParameterizedType)
+            .typeParameters
+            .map((t) => t.name),
+        typeArguments.map((t) =>
+            new DartObjectImpl(typeProvider.typeType, new TypeState(t))));
+
+    var fieldInitVisitor = new ConstantVisitor(this, errorReporter,
+        lexicalEnvironment: typeArgumentMap);
     // Start with final fields that are initialized at their declaration site.
-    for (FieldElement field in constructor.enclosingElement.fields) {
+    List<FieldElement> fields = constructor.enclosingElement.fields;
+    for (int i = 0; i < fields.length; i++) {
+      FieldElement field = fields[i];
       if ((field.isFinal || field.isConst) &&
           !field.isStatic &&
           field is ConstFieldElementImpl) {
         validator.beforeGetFieldEvaluationResult(field);
-        EvaluationResultImpl evaluationResult = field.evaluationResult;
+
+        DartObjectImpl fieldValue;
+        if (strongMode) {
+          var fieldInit = constructorBase.fieldInitializers[i].initializer;
+          fieldValue = fieldInit.accept(fieldInitVisitor);
+        } else {
+          fieldValue = field.evaluationResult?.value;
+        }
         // It is possible that the evaluation result is null.
         // This happens for example when we have duplicate fields.
         // class Test {final x = 1; final x = 2; const Test();}
-        if (evaluationResult == null) {
+        if (fieldValue == null) {
           continue;
         }
         // Match the value and the type.
         DartType fieldType =
             FieldMember.from(field, constructor.returnType).type;
-        DartObjectImpl fieldValue = evaluationResult.value;
         if (fieldValue != null && !runtimeTypeMatch(fieldValue, fieldType)) {
           errorReporter.reportErrorForNode(
               CheckedModeCompileTimeErrorCode
@@ -549,6 +573,14 @@ class ConstantEvaluationEngine {
         new HashMap<String, DartObjectImpl>();
     List<ParameterElement> parameters = constructor.parameters;
     int parameterCount = parameters.length;
+
+    HashMap<ParameterElement, DefaultFormalParameter> parameterDefaultMap;
+    if (strongMode) {
+      parameterDefaultMap = new HashMap.fromIterable(
+          constructorBase.parameterInitializers,
+          key: (p) => p.parameter.element);
+    }
+
     for (int i = 0; i < parameterCount; i++) {
       ParameterElement parameter = parameters[i];
       ParameterElement baseParameter = parameter;
@@ -574,12 +606,22 @@ class ConstantEvaluationEngine {
         // The parameter is an optional positional parameter for which no value
         // was provided, so use the default value.
         validator.beforeGetParameterDefault(baseParameter);
-        EvaluationResultImpl evaluationResult = baseParameter.evaluationResult;
-        if (evaluationResult == null) {
-          // No default was provided, so the default value is null.
-          argumentValue = typeProvider.nullObject;
-        } else if (evaluationResult.value != null) {
-          argumentValue = evaluationResult.value;
+        if (strongMode) {
+          var defaultValue = parameterDefaultMap[parameter]?.defaultValue;
+          if (defaultValue == null) {
+            argumentValue = typeProvider.nullObject;
+          } else {
+            argumentValue = defaultValue.accept(fieldInitVisitor);
+          }
+        } else {
+          EvaluationResultImpl evaluationResult =
+              baseParameter.evaluationResult;
+          if (evaluationResult == null) {
+            // No default was provided, so the default value is null.
+            argumentValue = typeProvider.nullObject;
+          } else if (evaluationResult.value != null) {
+            argumentValue = evaluationResult.value;
+          }
         }
       }
       if (argumentValue != null) {
@@ -661,6 +703,7 @@ class ConstantEvaluationEngine {
         if (constructor != null && constructor.isConst) {
           return evaluateConstructorCall(
               node,
+              typeArguments,
               initializer.argumentList.arguments,
               constructor,
               initializerVisitor,
@@ -677,8 +720,15 @@ class ConstantEvaluationEngine {
         if (superArguments == null) {
           superArguments = new NodeList<Expression>(null);
         }
-        evaluateSuperConstructorCall(node, fieldMap, superConstructor,
-            superArguments, initializerVisitor, errorReporter);
+
+        evaluateSuperConstructorCall(
+            node,
+            fieldMap,
+            superConstructor,
+            superclass.typeArguments,
+            superArguments,
+            initializerVisitor,
+            errorReporter);
       }
     }
     return new DartObjectImpl(definingClass, new GenericState(fieldMap));
@@ -688,12 +738,18 @@ class ConstantEvaluationEngine {
       AstNode node,
       HashMap<String, DartObjectImpl> fieldMap,
       ConstructorElement superConstructor,
-      NodeList<Expression> superArguments,
+      List<DartType> superTypeArguments,
+      List<Expression> superArguments,
       ConstantVisitor initializerVisitor,
       ErrorReporter errorReporter) {
     if (superConstructor != null && superConstructor.isConst) {
-      DartObjectImpl evaluationResult = evaluateConstructorCall(node,
-          superArguments, superConstructor, initializerVisitor, errorReporter);
+      DartObjectImpl evaluationResult = evaluateConstructorCall(
+          node,
+          superTypeArguments,
+          superArguments,
+          superConstructor,
+          initializerVisitor,
+          errorReporter);
       if (evaluationResult != null) {
         fieldMap[GenericState.SUPERCLASS_FIELD] = evaluationResult;
       }
@@ -1231,8 +1287,25 @@ class ConstantVisitor extends UnifyingAstVisitor<DartObjectImpl> {
       // problem - the error has already been reported.
       return null;
     }
-    return evaluationEngine.evaluateConstructorCall(
-        node, node.argumentList.arguments, constructor, this, _errorReporter);
+
+    var type = constructor.returnType as ParameterizedType;
+    var typeArguments = type.typeArguments.map((t) {
+      if (t is TypeParameterType && _lexicalEnvironment != null) {
+        return _lexicalEnvironment[t.name]?.toTypeValue() ?? t;
+      }
+      return t;
+    }).toList();
+
+    if (constructor is ConstructorMember) {
+      constructor = (constructor as ConstructorMember).baseElement;
+    }
+
+    constructor = ConstructorMember.from(
+        constructor,
+        type.substitute2(typeArguments, type.typeArguments));
+
+    return evaluationEngine.evaluateConstructorCall(node, typeArguments,
+        node.argumentList.arguments, constructor, this, _errorReporter);
   }
 
   @override
@@ -1465,6 +1538,16 @@ class ConstantVisitor extends UnifyingAstVisitor<DartObjectImpl> {
         _typeProvider.symbolType, new SymbolState(buffer.toString()));
   }
 
+  @override
+  DartObjectImpl visitTypeName(TypeName node) {
+    // TODO(jmesserly): what to do about type arguments?
+    String name = node.name.name;
+    if (_lexicalEnvironment != null && _lexicalEnvironment.containsKey(name)) {
+      return _lexicalEnvironment[name];
+    }
+    return new DartObjectImpl(_typeProvider.typeType, new TypeState(node.type));
+  }
+
   /**
    * Create an error associated with the given [node]. The error will have the
    * given error [code].
@@ -1497,10 +1580,9 @@ class ConstantVisitor extends UnifyingAstVisitor<DartObjectImpl> {
         }
         return new DartObjectImpl(functionType, new FunctionState(function));
       }
-    } else if (variableElement is ClassElement ||
-        variableElement is FunctionTypeAliasElement ||
-        variableElement is DynamicElementImpl) {
-      return new DartObjectImpl(_typeProvider.typeType, new TypeState(element));
+    } else if (variableElement is TypeDefiningElement) {
+      return new DartObjectImpl(
+          _typeProvider.typeType, new TypeState(variableElement.type));
     }
     // TODO(brianwilkerson) Figure out which error to report.
     _error(node, null);