Merge pull request #9407 from Microsoft/literalTypes

Number, enum, and boolean literal types

Author: ahejlsberg

src/compiler/binder.ts

@@ -618,18 +618,10 @@ namespace ts {
             return false;
         }
 
-        function isNarrowingNullCheckOperands(expr1: Expression, expr2: Expression) {
-            return (expr1.kind === SyntaxKind.NullKeyword || expr1.kind === SyntaxKind.Identifier && (<Identifier>expr1).text === "undefined") && isNarrowableOperand(expr2);
-        }
-
         function isNarrowingTypeofOperands(expr1: Expression, expr2: Expression) {
             return expr1.kind === SyntaxKind.TypeOfExpression && isNarrowableOperand((<TypeOfExpression>expr1).expression) && expr2.kind === SyntaxKind.StringLiteral;
         }
 
-        function isNarrowingDiscriminant(expr: Expression) {
-            return expr.kind === SyntaxKind.PropertyAccessExpression && isNarrowableReference((<PropertyAccessExpression>expr).expression);
-        }
-
         function isNarrowingBinaryExpression(expr: BinaryExpression) {
             switch (expr.operatorToken.kind) {
                 case SyntaxKind.EqualsToken:
@@ -638,9 +630,8 @@ namespace ts {
                 case SyntaxKind.ExclamationEqualsToken:
                 case SyntaxKind.EqualsEqualsEqualsToken:
                 case SyntaxKind.ExclamationEqualsEqualsToken:
-                    return isNarrowingNullCheckOperands(expr.right, expr.left) || isNarrowingNullCheckOperands(expr.left, expr.right) ||
-                        isNarrowingTypeofOperands(expr.right, expr.left) || isNarrowingTypeofOperands(expr.left, expr.right) ||
-                        isNarrowingDiscriminant(expr.left) || isNarrowingDiscriminant(expr.right);
+                    return isNarrowableOperand(expr.left) || isNarrowableOperand(expr.right) ||
+                        isNarrowingTypeofOperands(expr.right, expr.left) || isNarrowingTypeofOperands(expr.left, expr.right);
                 case SyntaxKind.InstanceOfKeyword:
                     return isNarrowableOperand(expr.left);
                 case SyntaxKind.CommaToken:
@@ -664,11 +655,6 @@ namespace ts {
             return isNarrowableReference(expr);
         }
 
-        function isNarrowingSwitchStatement(switchStatement: SwitchStatement) {
-            const expr = switchStatement.expression;
-            return expr.kind === SyntaxKind.PropertyAccessExpression && isNarrowableReference((<PropertyAccessExpression>expr).expression);
-        }
-
         function createBranchLabel(): FlowLabel {
             return {
                 flags: FlowFlags.BranchLabel,
@@ -718,7 +704,7 @@ namespace ts {
         }
 
         function createFlowSwitchClause(antecedent: FlowNode, switchStatement: SwitchStatement, clauseStart: number, clauseEnd: number): FlowNode {
-            if (!isNarrowingSwitchStatement(switchStatement)) {
+            if (!isNarrowingExpression(switchStatement.expression)) {
                 return antecedent;
             }
             setFlowNodeReferenced(antecedent);
@@ -1983,7 +1969,7 @@ namespace ts {
         function bindThisPropertyAssignment(node: BinaryExpression) {
             // Declare a 'member' in case it turns out the container was an ES5 class or ES6 constructor
             let assignee: Node;
-            if (container.kind === SyntaxKind.FunctionDeclaration || container.kind === SyntaxKind.FunctionDeclaration) {
+            if (container.kind === SyntaxKind.FunctionDeclaration || container.kind === SyntaxKind.FunctionExpression) {
                 assignee = container;
             }
             else if (container.kind === SyntaxKind.Constructor) {

src/compiler/checker.ts

@@ -93,10 +93,10 @@ namespace ts {
         return undefined;
     }
 
-    export function contains<T>(array: T[], value: T, areEqual?: (a: T, b: T) => boolean): boolean {
+    export function contains<T>(array: T[], value: T): boolean {
         if (array) {
             for (const v of array) {
-                if (areEqual ? areEqual(v, value) : v === value) {
+                if (v === value) {
                     return true;
                 }
             }
@@ -182,10 +182,13 @@ namespace ts {
         let result: T[];
         if (array) {
             result = [];
-            for (const item of array) {
-                if (!contains(result, item, areEqual)) {
-                    result.push(item);
+            loop: for (const item of array) {
+                for (const res of result) {
+                    if (areEqual ? areEqual(res, item) : res === item) {
+                        continue loop;
+                    }
                 }
+                result.push(item);
             }
         }
         return result;

src/compiler/core.ts

@@ -397,7 +397,7 @@ namespace ts {
                 case SyntaxKind.NullKeyword:
                 case SyntaxKind.NeverKeyword:
                 case SyntaxKind.ThisType:
-                case SyntaxKind.StringLiteralType:
+                case SyntaxKind.LiteralType:
                     return writeTextOfNode(currentText, type);
                 case SyntaxKind.ExpressionWithTypeArguments:
                     return emitExpressionWithTypeArguments(<ExpressionWithTypeArguments>type);

src/compiler/declarationEmitter.ts

@@ -1755,6 +1755,10 @@
         "category": "Error",
         "code": 2534
     },
+    "Enum type '{0}' has members with initializers that are not literals.": {
+        "category": "Error",
+        "code": 2535
+    },
     "JSX element attributes type '{0}' may not be a union type.": {
         "category": "Error",
         "code": 2600

src/compiler/diagnosticMessages.json

@@ -6045,7 +6045,7 @@ const _super = (function (geti, seti) {
                             return;
 
                         case SyntaxKind.StringKeyword:
-                        case SyntaxKind.StringLiteralType:
+                        case SyntaxKind.LiteralType:
                             write("String");
                             return;