Ensure that JSDoc parsing happens within a ParsingContext

Author: jakebailey

src/compiler/parser.ts

@@ -1446,6 +1446,8 @@ namespace Parser {
     let identifiers: Map<string, string>;
     let identifierCount: number;
 
+    // TODO(jakebailey): This type is a lie; this value actually contains the result
+    // of ORing a bunch of `1 << ParsingContext.XYZ`.
     let parsingContext: ParsingContext;
 
     let notParenthesizedArrow: Set<number> | undefined;
@@ -2824,9 +2826,13 @@ namespace Parser {
                 return tokenIsIdentifierOrKeyword(token()) || token() === SyntaxKind.OpenBraceToken;
             case ParsingContext.JsxChildren:
                 return true;
+            case ParsingContext.StandaloneJSDoc:
+                return true;
+            case ParsingContext.Count:
+                return Debug.fail("ParsingContext.Count used as a context"); // Not a real context, only a marker.
+            default:
+                Debug.assertNever(parsingContext, "Non-exhaustive case in 'isListElement'.");
         }
-
-        return Debug.fail("Non-exhaustive case in 'isListElement'.");
     }
 
     function isValidHeritageClauseObjectLiteral() {
@@ -2962,6 +2968,9 @@ namespace Parser {
 
     // True if positioned at element or terminator of the current list or any enclosing list
     function isInSomeParsingContext(): boolean {
+        // We should be in at least one parsing context, be it SourceElements while parsing
+        // a SourceFile, or StandaloneJSDoc when lazily parsing JSDoc.
+        Debug.assert(parsingContext, "Missing parsing context");
         for (let kind = 0; kind < ParsingContext.Count; kind++) {
             if (parsingContext & (1 << kind)) {
                 if (isListElement(kind, /*inErrorRecovery*/ true) || isListTerminator(kind)) {
@@ -3078,6 +3087,7 @@ namespace Parser {
             case ParsingContext.VariableDeclarations:
             case ParsingContext.JSDocParameters:
             case ParsingContext.Parameters:
+            case ParsingContext.StandaloneJSDoc: // TODO(jakebailey): is it?
                 return true;
         }
         return false;
@@ -3337,6 +3347,7 @@ namespace Parser {
             case ParsingContext.JsxAttributes: return parseErrorAtCurrentToken(Diagnostics.Identifier_expected);
             case ParsingContext.JsxChildren: return parseErrorAtCurrentToken(Diagnostics.Identifier_expected);
             case ParsingContext.AssertEntries: return parseErrorAtCurrentToken(Diagnostics.Identifier_or_string_literal_expected); // AssertionKey.
+            case ParsingContext.StandaloneJSDoc: return; // TODO(jakebailey): any error here?
             case ParsingContext.Count: return Debug.fail("ParsingContext.Count used as a context"); // Not a real context, only a marker.
             default: Debug.assertNever(context);
         }
@@ -7210,6 +7221,8 @@ namespace Parser {
 
     function tryReuseAmbientDeclaration(pos: number): Statement | undefined {
         return doInsideOfContext(NodeFlags.Ambient, () => {
+            // TODO(jakebailey): this is totally wrong; `parsingContext` is the result of ORing a bunch of `1 << ParsingContext.XYZ`.
+            // The enum should really be a bunch of flags.
             const node = currentNode(parsingContext, pos);
             if (node) {
                 return consumeNode(node) as Statement;
@@ -8397,7 +8410,8 @@ namespace Parser {
         TupleElementTypes,         // Element types in tuple element type list
         HeritageClauses,           // Heritage clauses for a class or interface declaration.
         ImportOrExportSpecifiers,  // Named import clause's import specifier list,
-        AssertEntries,               // Import entries list.
+        AssertEntries,             // Import entries list.
+        StandaloneJSDoc,           // TODO(jakebailey): describe
         Count                      // Number of parsing contexts
     }
 
@@ -8503,6 +8517,15 @@ namespace Parser {
         }
 
         function parseJSDocCommentWorker(start = 0, length: number | undefined): JSDoc | undefined {
+            const saveParsingContext = parsingContext;
+            parsingContext |= 1 << ParsingContext.StandaloneJSDoc;
+            const jsdoc = parseJSDocCommentWorkerWorker(start, length);
+            parsingContext = saveParsingContext;
+            return jsdoc;
+        }
+
+        // TODO(jakebailey): name
+        function parseJSDocCommentWorkerWorker(start: number, length: number | undefined): JSDoc | undefined {
             const content = sourceText;
             const end = length === undefined ? content.length : start + length;
             length = end - start;

tests/baselines/reference/jsDocDontBreakWithNamespaces.baseline

@@ -25,7 +25,7 @@
 // zee('');
 //       ^
 // | ----------------------------------------------------------------------
-// | zee(**arg0: any**, arg1: any, arg2: any): any
+// | zee(**arg0: any**, arg1: any): any
 // | ----------------------------------------------------------------------
 
 [
@@ -259,30 +259,6 @@
               ],
               "isOptional": false,
               "isRest": false
-            },
-            {
-              "name": "arg2",
-              "documentation": [],
-              "displayParts": [
-                {
-                  "text": "arg2",
-                  "kind": "parameterName"
-                },
-                {
-                  "text": ":",
-                  "kind": "punctuation"
-                },
-                {
-                  "text": " ",
-                  "kind": "space"
-                },
-                {
-                  "text": "any",
-                  "kind": "keyword"
-                }
-              ],
-              "isOptional": false,
-              "isRest": false
             }
           ],
           "documentation": [],

tests/baselines/reference/jsdocFunctionTypeFalsePositive.errors.txt

@@ -1,24 +1,12 @@
+/a.js(1,13): error TS1098: Type parameter list cannot be empty.
 /a.js(1,14): error TS1139: Type parameter declaration expected.
-/a.js(1,17): error TS1003: Identifier expected.
-/a.js(1,17): error TS1110: Type expected.
-/a.js(1,17): error TS8024: JSDoc '@param' tag has name '', but there is no parameter with that name.
-/a.js(1,18): error TS1005: '>' expected.
-/a.js(1,18): error TS1005: '}' expected.
 
 
-==== /a.js (6 errors) ====
+==== /a.js (2 errors) ====
     /** @param {<} x */
+                ~~
+!!! error TS1098: Type parameter list cannot be empty.
                  ~
 !!! error TS1139: Type parameter declaration expected.
-                    
-!!! error TS1003: Identifier expected.
-                    
-!!! error TS1110: Type expected.
-                    
-!!! error TS8024: JSDoc '@param' tag has name '', but there is no parameter with that name.
-                     
-!!! error TS1005: '>' expected.
-                     
-!!! error TS1005: '}' expected.
     function f(x) {}
 

tests/baselines/reference/jsdocFunctionTypeFalsePositive.types

@@ -1,6 +1,6 @@
 === /a.js ===
 /** @param {<} x */
 function f(x) {}
->f : (x: any) => void
->x : any
+>f : (x: () => any) => void
+>x : () => any
 

tests/cases/fourslash/badJSDocNoCrash.ts

@@ -8,4 +8,4 @@
 ////     constructor(options = {}) {}
 //// }
 
-verify.encodedSyntacticClassificationsLength(84);
+verify.encodedSyntacticClassificationsLength(69);