Remove redundant feature detection in Parser. These features are alre…

…ady detected in IRFactory.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=160658161

src/com/google/javascript/jscomp/parsing/IRFactory.java

@@ -1021,6 +1021,7 @@ Node processObjectPattern(ObjectPatternTree tree) {
     }
 
     Node processAssignmentRestElement(AssignmentRestElementTree tree) {
+      maybeWarnForFeature(tree, Feature.ARRAY_PATTERN_REST);
       return newNode(Token.REST, transformNodeWithInlineJsDoc(tree.assignmentTarget));
     }
 

src/com/google/javascript/jscomp/parsing/parser/Parser.java

@@ -948,7 +948,6 @@ private ParseTree parseAsyncMethod() {
   }
 
   private ParseTree parseAsyncMethod(PartialClassElement partial) {
-    features = features.with(Feature.ASYNC_FUNCTIONS);
     eatPredefinedString(ASYNC);
     if (peekIdOrKeyword()) {
       IdentifierToken name = eatIdOrKeywordAsId();
@@ -1214,7 +1213,6 @@ private ParseTree parseFunctionExpression() {
 
   private ParseTree parseAsyncFunctionDeclaration() {
     SourcePosition start = getTreeStartLocation();
-    features = features.with(Feature.ASYNC_FUNCTIONS);
     eatAsyncFunctionStart();
 
     if (peek(TokenType.STAR)) {
@@ -1234,7 +1232,6 @@ private ParseTree parseAsyncFunctionDeclaration() {
 
   private ParseTree parseAsyncFunctionExpression() {
     SourcePosition start = getTreeStartLocation();
-    features = features.with(Feature.ASYNC_FUNCTIONS);
     eatAsyncFunctionStart();
 
     if (peek(TokenType.STAR)) {
@@ -1314,7 +1311,6 @@ private ParseTree parseParameter(ParamContext context) {
     if (context == ParamContext.IMPLEMENTATION
         && !parameter.isRestParameter()
         && peek(TokenType.EQUAL)) {
-      features = features.with(Feature.DEFAULT_PARAMETERS);
       eat(TokenType.EQUAL);
       ParseTree defaultValue = parseAssignmentExpression();
       parameter = new DefaultParameterTree(getTreeLocation(start), parameter, defaultValue);
@@ -1329,7 +1325,6 @@ && peek(TokenType.EQUAL)) {
   }
 
   private ParseTree parseRestParameter() {
-    features = features.with(Feature.REST_PARAMETERS);
     SourcePosition start = getTreeStartLocation();
     eat(TokenType.SPREAD);
     return new RestParameterTree(
@@ -1709,17 +1704,11 @@ private VariableDeclarationListTree parseVariableDeclarationList(
     TokenType token = peekType();
 
     switch (token) {
-    case CONST:
-      features = features.with(Feature.CONST_DECLARATIONS);
-      eat(token);
-      break;
-    case LET:
-      features = features.with(Feature.LET_DECLARATIONS);
-      eat(token);
-      break;
-    case VAR:
-      eat(token);
-      break;
+      case CONST:
+      case LET:
+      case VAR:
+        eat(token);
+        break;
     default:
       reportError(peekToken(), "expected declaration");
       return null;
@@ -1926,10 +1915,8 @@ private void checkVanillaForInitializers(VariableDeclarationListTree variables)
   /** Reports if declaration requires an initializer, assuming initializer is absent. */
   private void maybeReportNoInitializer(TokenType token, ParseTree lvalue) {
     if (token == TokenType.CONST) {
-      features = features.with(Feature.CONST_DECLARATIONS);
       reportError("const variables must have an initializer");
     } else if (lvalue.isPattern()) {
-      features = features.with(Feature.DESTRUCTURING);
       reportError("destructuring must have an initializer");
     }
   }
@@ -2828,9 +2815,6 @@ private ParseTree parseAssignment(Expression expressionIn) {
         reportError("invalid assignment target");
       }
       Token operator = nextToken();
-      if (TokenType.STAR_STAR_EQUAL.equals(operator.type)) {
-        features = features.with(Feature.EXPONENT_OP);
-      }
       ParseTree right = parseAssignment(expressionIn);
       return new BinaryOperatorTree(getTreeLocation(start), left, operator, right);
     }
@@ -2877,7 +2861,6 @@ private ParseTree completeAssignmentExpressionParseAtArrow(
 
   private ParseTree completeArrowFunctionParseAtArrow(
       ParseTree leftOfArrow, Expression expressionIn) {
-    features = features.with(Feature.ARROW_FUNCTIONS);
     FormalParameterListTree arrowFormalParameters = transformToArrowFormalParameters(leftOfArrow);
     if (peekImplicitSemiColon()) {
       reportError("No newline allowed before '=>'");
@@ -2939,7 +2922,6 @@ private ParseTree completeAssignmentExpressionParseAtArrow(CallExpressionTree ca
 
   private ParseTree parseAsyncArrowFunction(Expression expressionIn) {
     SourcePosition start = getTreeStartLocation();
-    features = features.with(Feature.ARROW_FUNCTIONS, Feature.ASYNC_FUNCTIONS);
     eatPredefinedString(ASYNC);
     if (peekImplicitSemiColon()) {
       reportError("No newline allowed between `async` and arrow function parameter list");
@@ -3275,7 +3257,6 @@ private ParseTree parseExponentiationExpression() {
             "Unary operator '%s' requires parentheses before '**'",
             left.asUnaryExpression().operator);
       }
-      features = features.with(Feature.EXPONENT_OP);
       Token operator = nextToken();
       ParseTree right = parseExponentiationExpression();
       return new BinaryOperatorTree(getTreeLocation(start), left, operator, right);
@@ -3471,7 +3452,6 @@ private ParseTree parseNewExpression() {
 
   private ParseTree parseNewDotSomething() {
     // currently only "target" is valid after "new."
-    features = features.with(Feature.NEW_TARGET);
     SourcePosition start = getTreeStartLocation();
     eat(TokenType.NEW);
     eat(TokenType.PERIOD);
@@ -3540,7 +3520,6 @@ private boolean peekPatternStart() {
   }
 
   private ParseTree parsePattern(PatternKind kind) {
-    features = features.with(Feature.DESTRUCTURING);
     switch (peekType()) {
       case OPEN_SQUARE:
         return parseArrayPattern(kind);
@@ -3566,7 +3545,6 @@ private ParseTree parseArrayPatternElement(PatternKind patternKind) {
   }
 
   private ParseTree parseArrayPatternRest(PatternKind patternKind) {
-    features = features.with(Feature.ARRAY_PATTERN_REST);
     SourcePosition start = getTreeStartLocation();
     eat(TokenType.SPREAD);
     ParseTree patternAssignmentTarget = parseRestAssignmentTarget(patternKind);
@@ -3583,7 +3561,6 @@ private ParseTree parseRestAssignmentTarget(PatternKind patternKind) {
 
   // Pattern ::= ... | "[" Element? ("," Element?)* "]"
   private ParseTree parseArrayPattern(PatternKind kind) {
-    features = features.with(Feature.DESTRUCTURING);
     SourcePosition start = getTreeStartLocation();
     ImmutableList.Builder<ParseTree> elements = ImmutableList.builder();
     eat(TokenType.OPEN_SQUARE);
@@ -3613,7 +3590,6 @@ private ParseTree parseArrayPattern(PatternKind kind) {
 
   // Pattern ::= "{" (Field ("," Field)* ","?)? "}" | ...
   private ParseTree parseObjectPattern(PatternKind kind) {
-    features = features.with(Feature.DESTRUCTURING);
     SourcePosition start = getTreeStartLocation();
     ImmutableList.Builder<ParseTree> fields = ImmutableList.builder();
     eat(TokenType.OPEN_CURLY);