Minor change to getStringLiteralType

Author: rbuckton

src/compiler/checker.ts

@@ -4531,8 +4531,7 @@ namespace ts {
  return links.resolvedType;
  }
 
- function getStringLiteralType(node: StringLiteral | StringLiteralTypeNode): StringLiteralType {
- const text = node.text;
+ function getStringLiteralType(text: string): StringLiteralType {
  if (hasProperty(stringLiteralTypes, text)) {
  return stringLiteralTypes[text];
  }
@@ -4545,7 +4544,7 @@ namespace ts {
  function getTypeFromStringLiteral(node: StringLiteral | StringLiteralTypeNode): Type {
  const links = getNodeLinks(node);
  if (!links.resolvedType) {
- links.resolvedType = getStringLiteralType(node);
+ links.resolvedType = getStringLiteralType(node.text);
  }
  return links.resolvedType;
  }
@@ -8747,7 +8746,7 @@ namespace ts {
  // for the argument. In that case, we should check the argument.
  if (argType === undefined) {
  argType = arg.kind === SyntaxKind.StringLiteral && !reportErrors
- ? getStringLiteralType(<StringLiteral>arg)
+ ? getStringLiteralType((<StringLiteral>arg).text)
  : checkExpressionWithContextualType(arg, paramType, excludeArgument && excludeArgument[i] ? identityMapper : undefined);
  }
 
@@ -8942,7 +8941,7 @@ namespace ts {
  case SyntaxKind.Identifier:
  case SyntaxKind.NumericLiteral:
  case SyntaxKind.StringLiteral:
- return getStringLiteralType(<StringLiteral>element.name);
+ return getStringLiteralType((<Identifier | LiteralExpression>element.name).text);
 
  case SyntaxKind.ComputedPropertyName:
  const nameType = checkComputedPropertyName(<ComputedPropertyName>element.name);
@@ -10564,7 +10563,8 @@ namespace ts {
  function checkStringLiteralExpression(node: StringLiteral): Type {
  const contextualType = getContextualType(node);
  if (contextualType && contextualTypeIsStringLiteralType(contextualType)) {
- return getStringLiteralType(node);
+ // TODO (drosen): Consider using getTypeFromStringLiteral instead
+ return getStringLiteralType(node.text);
  }
 
  return stringType;