Handle jsdoc backticks in the parser, not scanner

Previously, the jsdoc scanner had ad-hoc handling of backticks that was
similar in structure to the normal scanner's handling, but much simpler.
This was a smaller code change, but is handled backwards: the special
case of backtick-quoted parameter names was handled in the scanner
instead of in the jsdoc identifier parsing code. That made it overapply
and block correct handling of asterisks across newlines, which was most
obvious in code fences inside jsdoc, as in #23517.

Fixes #23517

Author: sandersn

src/compiler/parser.ts

@@ -6337,7 +6337,14 @@ namespace ts {
                 const hasBrace = (mayOmitBraces ? parseOptional : parseExpected)(SyntaxKind.OpenBraceToken);
                 result.type = doInsideOfContext(NodeFlags.JSDoc, parseJSDocType);
                 if (!mayOmitBraces || hasBrace) {
-                    parseExpected(SyntaxKind.CloseBraceToken);
+                    // parseExpected(SyntaxKind.CloseBraceToken); // TODO: need a parseExpectedJSDoc (and rename -> parseOptionalJSDoc)
+                    if (token() === SyntaxKind.CloseBraceToken) {
+                        nextJSDocToken();
+                    }
+                    else {
+                        parseErrorAtCurrentToken(Diagnostics._0_expected, tokenToString(SyntaxKind.CloseBraceToken));
+                    }
+
                 }
 
                 fixupParentReferences(result);
@@ -6722,13 +6729,17 @@ namespace ts {
                 }
 
                 function parseBracketNameInPropertyAndParamTag(): { name: EntityName, isBracketed: boolean } {
-                    if (token() === SyntaxKind.NoSubstitutionTemplateLiteral) {
-                        // a markdown-quoted name: `arg` is not legal jsdoc, but occurs in the wild
-                        return { name: createIdentifier(/*isIdentifier*/ true), isBracketed: false };
-                    }
                     // Looking for something like '[foo]', 'foo', '[foo.bar]' or 'foo.bar'
-                    const isBracketed = parseOptional(SyntaxKind.OpenBracketToken);
+                    const isBracketed = parseOptionalJsdoc(SyntaxKind.OpenBracketToken);
+                    if (isBracketed) {
+                        skipWhitespace();
+                    }
+                    // a markdown-quoted name: `arg` is not legal jsdoc, but occurs in the wild
+                    const isBackquoted = parseOptionalJsdoc(SyntaxKind.NoSubstitutionTemplateLiteral);
                     const name = parseJSDocEntityName();
+                    if (isBackquoted) {
+                        parseExpectedToken(SyntaxKind.NoSubstitutionTemplateLiteral);
+                    }
                     if (isBracketed) {
                         skipWhitespace();
 
@@ -7101,10 +7112,6 @@ namespace ts {
                     return result;
                 }
 
-                function nextJSDocToken(): JsDocSyntaxKind {
-                    return currentToken = scanner.scanJSDocToken();
-                }
-
                 function parseOptionalJsdoc(t: JsDocSyntaxKind): boolean {
                     if (token() === t) {
                         nextJSDocToken();
@@ -7146,6 +7153,10 @@ namespace ts {
                     return result;
                 }
             }
+
+            function nextJSDocToken(): JsDocSyntaxKind {
+                return currentToken = scanner.scanJSDocToken();
+            }
         }
     }
 

src/compiler/scanner.ts

@@ -2093,14 +2093,7 @@ namespace ts {
                 case CharacterCodes.dot:
                     return token = SyntaxKind.DotToken;
                 case CharacterCodes.backtick:
-                    if (pos < end && text.charCodeAt(pos) !== CharacterCodes.backtick && text.charCodeAt(pos) !== CharacterCodes.carriageReturn && text.charCodeAt(pos) !== CharacterCodes.lineFeed) {
-                        while (pos < end && text.charCodeAt(pos) !== CharacterCodes.backtick) {
-                            pos++;
-                        }
-                        tokenValue = text.substring(tokenPos + 1, pos);
-                        pos++;
-                        return token = SyntaxKind.NoSubstitutionTemplateLiteral;
-                    }
+                    return token = SyntaxKind.NoSubstitutionTemplateLiteral;
             }
 
             if (isIdentifierStart(ch, ScriptTarget.Latest)) {

src/compiler/types.ts

@@ -181,6 +181,7 @@ namespace ts {
         QuestionToken,
         ColonToken,
         AtToken,
+        // BacktickToken, // TODO: Sure would be nice! But only JSDoc would use it, which would be super confusing
         // Assignments
         EqualsToken,
         PlusEqualsToken,

tests/baselines/reference/JSDocParsing/DocComments.parsesCorrectly.paramTagNameThenType1.json

@@ -8,7 +8,7 @@
         "0": {
             "kind": "JSDocParameterTag",
             "pos": 8,
-            "end": 29,
+            "end": 32,
             "modifierFlagsCache": 0,
             "transformFlags": 0,
             "tagName": {
@@ -46,6 +46,6 @@
         },
         "length": 1,
         "pos": 8,
-        "end": 29
+        "end": 32
     }
 }

tests/baselines/reference/paramTagWrapping.errors.txt

@@ -2,8 +2,8 @@ tests/cases/conformance/jsdoc/bad.js(2,11): error TS1003: Identifier expected.
 tests/cases/conformance/jsdoc/bad.js(2,11): error TS8024: JSDoc '@param' tag has name '', but there is no parameter with that name.
 tests/cases/conformance/jsdoc/bad.js(5,4): error TS1003: Identifier expected.
 tests/cases/conformance/jsdoc/bad.js(5,4): error TS8024: JSDoc '@param' tag has name '', but there is no parameter with that name.
-tests/cases/conformance/jsdoc/bad.js(6,19): error TS1003: Identifier expected.
-tests/cases/conformance/jsdoc/bad.js(6,19): error TS8024: JSDoc '@param' tag has name '', but there is no parameter with that name.
+tests/cases/conformance/jsdoc/bad.js(6,20): error TS1003: Identifier expected.
+tests/cases/conformance/jsdoc/bad.js(6,20): error TS8024: JSDoc '@param' tag has name '', but there is no parameter with that name.
 tests/cases/conformance/jsdoc/bad.js(9,14): error TS7006: Parameter 'x' implicitly has an 'any' type.
 tests/cases/conformance/jsdoc/bad.js(9,17): error TS7006: Parameter 'y' implicitly has an 'any' type.
 tests/cases/conformance/jsdoc/bad.js(9,20): error TS7006: Parameter 'z' implicitly has an 'any' type.
@@ -39,9 +39,9 @@ tests/cases/conformance/jsdoc/bad.js(9,20): error TS7006: Parameter 'z' implicit
 
 !!! error TS8024: JSDoc '@param' tag has name '', but there is no parameter with that name.
      * @param {number} * z
-                      
+                       
 !!! error TS1003: Identifier expected.
-                      
+                       
 !!! error TS8024: JSDoc '@param' tag has name '', but there is no parameter with that name.
      * Arg z.
      */