Better JSDoc generic errors and faster isInJSDoc

Author: sandersn

src/compiler/checker.ts

@@ -18454,8 +18454,9 @@ namespace ts {
 
         function checkTypeReferenceNode(node: TypeReferenceNode | ExpressionWithTypeArguments) {
             checkGrammarTypeArguments(node, node.typeArguments);
-            if (node.kind === SyntaxKind.TypeReference && node.typeName.jsdocDot && !isInJavaScriptFile(node) && !findAncestor(node, n => n.kind === SyntaxKind.JSDocTypeExpression)) {
-                grammarErrorOnNode(node, Diagnostics.JSDoc_types_can_only_be_used_inside_documentation_comments);
+            if (node.kind === SyntaxKind.TypeReference && node.typeName.jsdocDotPos !== undefined && !isInJavaScriptFile(node) && !isInJSDoc(node)) {
+                grammarErrorAtPos(getSourceFileOfNode(node), node.typeName.jsdocDotPos, 1, Diagnostics.JSDoc_types_can_only_be_used_inside_documentation_comments);
+
             }
             const type = getTypeFromTypeReference(node);
             if (type !== unknownType) {
@@ -22046,7 +22047,7 @@ namespace ts {
                 case SyntaxKind.JSDocNullableType:
                 case SyntaxKind.JSDocAllType:
                 case SyntaxKind.JSDocUnknownType:
-                    if (!isInJavaScriptFile(node) && !findAncestor(node, n => n.kind === SyntaxKind.JSDocTypeExpression)) {
+                    if (!isInJavaScriptFile(node) && !isInJSDoc(node)) {
                         grammarErrorOnNode(node, Diagnostics.JSDoc_types_can_only_be_used_inside_documentation_comments);
                     }
                     return;

src/compiler/parser.ts

@@ -1925,10 +1925,11 @@ namespace ts {
         // The allowReservedWords parameter controls whether reserved words are permitted after the first dot
         function parseEntityName(allowReservedWords: boolean, diagnosticMessage?: DiagnosticMessage): EntityName {
             let entity: EntityName = allowReservedWords ? parseIdentifierName() : parseIdentifier(diagnosticMessage);
+            let dotPos = scanner.getStartPos();
             while (parseOptional(SyntaxKind.DotToken)) {
                 if (token() === SyntaxKind.LessThanToken) {
-                    // the entity is part of a JSDoc-style generic, so record this for later in case it's an error
-                    entity.jsdocDot = true;
+                    // the entity is part of a JSDoc-style generic, so record the trailing dot for later error reporting
+                    entity.jsdocDotPos = dotPos;
                     break;
                 }
                 const node: QualifiedName = <QualifiedName>createNode(SyntaxKind.QualifiedName, entity.pos);

src/compiler/types.ts

@@ -576,7 +576,7 @@ namespace ts {
         /*@internal*/ autoGenerateId?: number;                    // Ensures unique generated identifiers get unique names, but clones get the same name.
         isInJSDocNamespace?: boolean;                             // if the node is a member in a JSDoc namespace
         /*@internal*/ typeArguments?: NodeArray<TypeNode>;        // Only defined on synthesized nodes. Though not syntactically valid, used in emitting diagnostics.
-        /*@internal*/ jsdocDot?: boolean;                         // Identifier occurs in JSDoc-style generic: Id.<T>
+        /*@internal*/ jsdocDotPos?: number;                       // Identifier occurs in JSDoc-style generic: Id.<T>
     }
 
     // Transient identifier node (marked by id === -1)
@@ -596,7 +596,7 @@ namespace ts {
         kind: SyntaxKind.QualifiedName;
         left: EntityName;
         right: Identifier;
-        /*@internal*/ jsdocDot?: boolean; // Identifier occurs in JSDoc-style generic: Id1.Id2.<T>
+        /*@internal*/ jsdocDotPos?: number;                      // QualifiedName occurs in JSDoc-style generic: Id1.Id2.<T>
     }
 
     export type EntityName = Identifier | QualifiedName;

src/compiler/utilities.ts

@@ -1292,6 +1292,10 @@ namespace ts {
         return node && !!(node.flags & NodeFlags.JavaScriptFile);
     }
 
+    export function isInJSDoc(node: Node): boolean {
+        return node && !!(node.flags & NodeFlags.JSDoc);
+    }
+
     /**
      * Returns true if the node is a CallExpression to the identifier 'require' with
      * exactly one argument (of the form 'require("name")').
@@ -3299,7 +3303,7 @@ namespace ts {
     }
 
     export function isJSDocTypeReference(node: TypeReferenceType): node is TypeReferenceNode {
-        return node.kind === SyntaxKind.TypeReference && !!findAncestor(node, n => n.kind === SyntaxKind.JSDocTypeExpression);
+        return node.flags & NodeFlags.JSDoc && node.kind === SyntaxKind.TypeReference;
     }
 
     /**