Merge pull request #14443 from Microsoft/specific_types

Use more specific types in a few cases

Author: Andy

src/compiler/factory.ts

@@ -1486,7 +1486,7 @@ namespace ts {
 
     // Clauses
 
-    export function createHeritageClause(token: SyntaxKind, types: ExpressionWithTypeArguments[]) {
+    export function createHeritageClause(token: HeritageClause["token"], types: ExpressionWithTypeArguments[]) {
         const node = <HeritageClause>createSynthesizedNode(SyntaxKind.HeritageClause);
         node.token = token;
         node.types = createNodeArray(types);

src/compiler/parser.ts

@@ -5437,9 +5437,10 @@ namespace ts {
         }
 
         function parseHeritageClause(): HeritageClause | undefined {
-            if (token() === SyntaxKind.ExtendsKeyword || token() === SyntaxKind.ImplementsKeyword) {
+            const tok = token();
+            if (tok === SyntaxKind.ExtendsKeyword || tok === SyntaxKind.ImplementsKeyword) {
                 const node = <HeritageClause>createNode(SyntaxKind.HeritageClause);
-                node.token = token();
+                node.token = tok;
                 nextToken();
                 node.types = parseDelimitedList(ParsingContext.HeritageClauseElement, parseExpressionWithTypeArguments);
                 return finishNode(node);

src/compiler/types.ts

@@ -863,15 +863,13 @@ namespace ts {
         kind: SyntaxKind.ThisType;
     }
 
-    export interface FunctionOrConstructorTypeNode extends TypeNode, SignatureDeclaration {
-        kind: SyntaxKind.FunctionType | SyntaxKind.ConstructorType;
-    }
+    export type FunctionOrConstructorTypeNode = FunctionTypeNode | ConstructorTypeNode;
 
-    export interface FunctionTypeNode extends FunctionOrConstructorTypeNode {
+    export interface FunctionTypeNode extends TypeNode, SignatureDeclaration {
         kind: SyntaxKind.FunctionType;
     }
 
-    export interface ConstructorTypeNode extends FunctionOrConstructorTypeNode {
+    export interface ConstructorTypeNode extends TypeNode, SignatureDeclaration {
         kind: SyntaxKind.ConstructorType;
     }
 
@@ -908,17 +906,16 @@ namespace ts {
         elementTypes: NodeArray<TypeNode>;
     }
 
-    export interface UnionOrIntersectionTypeNode extends TypeNode {
-        kind: SyntaxKind.UnionType | SyntaxKind.IntersectionType;
-        types: NodeArray<TypeNode>;
-    }
+    export type UnionOrIntersectionTypeNode = UnionTypeNode | IntersectionTypeNode;
 
-    export interface UnionTypeNode extends UnionOrIntersectionTypeNode {
+    export interface UnionTypeNode extends TypeNode {
         kind: SyntaxKind.UnionType;
+        types: NodeArray<TypeNode>;
     }
 
-    export interface IntersectionTypeNode extends UnionOrIntersectionTypeNode {
+    export interface IntersectionTypeNode extends TypeNode {
         kind: SyntaxKind.IntersectionType;
+        types: NodeArray<TypeNode>;
     }
 
     export interface ParenthesizedTypeNode extends TypeNode {
@@ -1779,7 +1776,7 @@ namespace ts {
     export interface HeritageClause extends Node {
         kind: SyntaxKind.HeritageClause;
         parent?: InterfaceDeclaration | ClassDeclaration | ClassExpression;
-        token: SyntaxKind;
+        token: SyntaxKind.ExtendsKeyword | SyntaxKind.ImplementsKeyword;
         types?: NodeArray<ExpressionWithTypeArguments>;
     }