Only issue matching token errors on non-dupe locations (microsoft#43460)

* Only issue matching token errors on non-dupe locations

Intead of unconditionally retrieving the last error and attaching a
related span, `parseErrorAt` and friends now return the last error and
return `false` when there is none.

Also make one more place use parseExpectedMatchingBrackets that I missed
last time.

* Inline parseTokenForError, return undefined not false

* skip redundant undefined assignment

* address PR comments

Author: sandersn

src/compiler/parser.ts

@@ -1335,24 +1335,27 @@ namespace ts {
             return inContext(NodeFlags.AwaitContext);
         }
 
-        function parseErrorAtCurrentToken(message: DiagnosticMessage, arg0?: any): void {
-            parseErrorAt(scanner.getTokenPos(), scanner.getTextPos(), message, arg0);
+        function parseErrorAtCurrentToken(message: DiagnosticMessage, arg0?: any): DiagnosticWithDetachedLocation | undefined {
+            return parseErrorAt(scanner.getTokenPos(), scanner.getTextPos(), message, arg0);
         }
 
-        function parseErrorAtPosition(start: number, length: number, message: DiagnosticMessage, arg0?: any): void {
+        function parseErrorAtPosition(start: number, length: number, message: DiagnosticMessage, arg0?: any): DiagnosticWithDetachedLocation | undefined {
             // Don't report another error if it would just be at the same position as the last error.
             const lastError = lastOrUndefined(parseDiagnostics);
+            let result: DiagnosticWithDetachedLocation | undefined;
             if (!lastError || start !== lastError.start) {
-                parseDiagnostics.push(createDetachedDiagnostic(fileName, start, length, message, arg0));
+                result = createDetachedDiagnostic(fileName, start, length, message, arg0);
+                parseDiagnostics.push(result);
             }
 
             // Mark that we've encountered an error.  We'll set an appropriate bit on the next
             // node we finish so that it can't be reused incrementally.
             parseErrorBeforeNextFinishedNode = true;
+            return result;
         }
 
-        function parseErrorAt(start: number, end: number, message: DiagnosticMessage, arg0?: any): void {
-            parseErrorAtPosition(start, end - start, message, arg0);
+        function parseErrorAt(start: number, end: number, message: DiagnosticMessage, arg0?: any): DiagnosticWithDetachedLocation | undefined {
+            return parseErrorAtPosition(start, end - start, message, arg0);
         }
 
         function parseErrorAtRange(range: TextRange, message: DiagnosticMessage, arg0?: any): void {
@@ -1543,17 +1546,17 @@ namespace ts {
         }
 
         function parseExpectedMatchingBrackets(openKind: SyntaxKind, closeKind: SyntaxKind, openPosition: number) {
-            if (!parseExpected(closeKind)) {
-                const lastError = lastOrUndefined(parseDiagnostics);
-                if (lastError && lastError.code === Diagnostics._0_expected.code) {
-                    addRelatedInfo(
-                        lastError,
-                        createDetachedDiagnostic(fileName, openPosition, 1, Diagnostics.The_parser_expected_to_find_a_1_to_match_the_0_token_here, tokenToString(openKind), tokenToString(closeKind))
-                    );
-                }
-                return false;
+            if (token() === closeKind) {
+                nextToken();
+                return;
+            }
+            const lastError = parseErrorAtCurrentToken(Diagnostics._0_expected, tokenToString(closeKind));
+            if (lastError) {
+                addRelatedInfo(
+                    lastError,
+                    createDetachedDiagnostic(fileName, openPosition, 1, Diagnostics.The_parser_expected_to_find_a_1_to_match_the_0_token_here, tokenToString(openKind), tokenToString(closeKind))
+                );
             }
-            return true;
         }
 
         function parseOptional(t: SyntaxKind): boolean {
@@ -5513,15 +5516,7 @@ namespace ts {
             parseExpected(SyntaxKind.OpenBraceToken);
             const multiLine = scanner.hasPrecedingLineBreak();
             const properties = parseDelimitedList(ParsingContext.ObjectLiteralMembers, parseObjectLiteralElement, /*considerSemicolonAsDelimiter*/ true);
-            if (!parseExpected(SyntaxKind.CloseBraceToken)) {
-                const lastError = lastOrUndefined(parseDiagnostics);
-                if (lastError && lastError.code === Diagnostics._0_expected.code) {
-                    addRelatedInfo(
-                        lastError,
-                        createDetachedDiagnostic(fileName, openBracePosition, 1, Diagnostics.The_parser_expected_to_find_a_1_to_match_the_0_token_here, tokenToString(SyntaxKind.OpenBraceToken), tokenToString(SyntaxKind.CloseBraceToken))
-                    );
-                }
-            }
+            parseExpectedMatchingBrackets(SyntaxKind.OpenBraceToken, SyntaxKind.CloseBraceToken, openBracePosition);
             return finishNode(factory.createObjectLiteralExpression(properties, multiLine), pos);
         }
 
@@ -7984,13 +7979,9 @@ namespace ts {
                             hasChildren = true;
                             if (child.kind === SyntaxKind.JSDocTypeTag) {
                                 if (childTypeTag) {
-                                    parseErrorAtCurrentToken(Diagnostics.A_JSDoc_typedef_comment_may_not_contain_multiple_type_tags);
-                                    const lastError = lastOrUndefined(parseDiagnostics);
+                                    const lastError = parseErrorAtCurrentToken(Diagnostics.A_JSDoc_typedef_comment_may_not_contain_multiple_type_tags);
                                     if (lastError) {
-                                        addRelatedInfo(
-                                            lastError,
-                                            createDetachedDiagnostic(fileName, 0, 0, Diagnostics.The_tag_was_first_specified_here)
-                                        );
+                                        addRelatedInfo(lastError, createDetachedDiagnostic(fileName, 0, 0, Diagnostics.The_tag_was_first_specified_here));
                                     }
                                     break;
                                 }

tests/baselines/reference/constructorWithIncompleteTypeAnnotation.errors.txt

@@ -505,7 +505,6 @@ tests/cases/compiler/constructorWithIncompleteTypeAnnotation.ts(261,1): error TS
 !!! error TS1135: Argument expression expected.
                                     ~
 !!! error TS1005: '(' expected.
-!!! related TS1007 tests/cases/compiler/constructorWithIncompleteTypeAnnotation.ts:257:33: The parser expected to find a ')' to match the '(' token here.
                                       ~~~~~~
 !!! error TS2693: 'string' only refers to a type, but is being used as a value here.
                                               ~~~

tests/baselines/reference/destructuringParameterDeclaration2.errors.txt

@@ -39,7 +39,6 @@ tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts(
 !!! error TS2322: Type 'string' is not assignable to type 'number'.
                                 ~
 !!! error TS1005: ',' expected.
-!!! related TS1007 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts:7:4: The parser expected to find a ']' to match the '[' token here.
     a0([1, 2, [["world"]], "string"]);  // Error
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2345: Argument of type '[number, number, string[][], string]' is not assignable to parameter of type '[number, number, string[][]]'.

tests/baselines/reference/errorRecoveryWithDotFollowedByNamespaceKeyword.errors.txt

@@ -16,5 +16,4 @@ tests/cases/compiler/errorRecoveryWithDotFollowedByNamespaceKeyword.ts(9,2): err
     }
 
 !!! error TS1005: '}' expected.
-!!! related TS1007 tests/cases/compiler/errorRecoveryWithDotFollowedByNamespaceKeyword.ts:3:19: The parser expected to find a '}' to match the '{' token here.
-!!! related TS1007 tests/cases/compiler/errorRecoveryWithDotFollowedByNamespaceKeyword.ts:2:20: The parser expected to find a '}' to match the '{' token here.
+!!! related TS1007 tests/cases/compiler/errorRecoveryWithDotFollowedByNamespaceKeyword.ts:3:19: The parser expected to find a '}' to match the '{' token here.

tests/baselines/reference/nestedClassDeclaration.errors.txt

@@ -32,7 +32,6 @@ tests/cases/conformance/classes/nestedClassDeclaration.ts(17,1): error TS1128: D
 !!! error TS2304: Cannot find name 'C4'.
                  ~
 !!! error TS1005: ',' expected.
-!!! related TS1007 tests/cases/conformance/classes/nestedClassDeclaration.ts:14:9: The parser expected to find a '}' to match the '{' token here.
         }
     }
     ~

tests/baselines/reference/objectLiteralWithSemicolons4.errors.txt

@@ -9,5 +9,4 @@ tests/cases/compiler/objectLiteralWithSemicolons4.ts(3,1): error TS1005: ',' exp
 !!! error TS18004: No value exists in scope for the shorthand property 'a'. Either declare one or provide an initializer.
     ;
     ~
-!!! error TS1005: ',' expected.
-!!! related TS1007 tests/cases/compiler/objectLiteralWithSemicolons4.ts:1:9: The parser expected to find a '}' to match the '{' token here.
+!!! error TS1005: ',' expected.

tests/baselines/reference/objectSpreadNegativeParse.errors.txt

@@ -28,7 +28,6 @@ tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(4,20): error T
 !!! error TS2304: Cannot find name 'matchMedia'.
                                ~
 !!! error TS1005: ',' expected.
-!!! related TS1007 tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts:3:10: The parser expected to find a '}' to match the '{' token here.
                                   ~
 !!! error TS1128: Declaration or statement expected.
     let o10 = { ...get x() { return 12; }};

tests/baselines/reference/parseErrorIncorrectReturnToken.errors.txt

@@ -25,7 +25,6 @@ tests/cases/compiler/parseErrorIncorrectReturnToken.ts(12,1): error TS1128: Decl
         m(n: number) => string {
                      ~~
 !!! error TS1005: '{' expected.
-!!! related TS1007 tests/cases/compiler/parseErrorIncorrectReturnToken.ts:8:9: The parser expected to find a '}' to match the '{' token here.
                         ~~~~~~
 !!! error TS2693: 'string' only refers to a type, but is being used as a value here.
                                ~

tests/baselines/reference/parserErrorRecoveryArrayLiteralExpression3.errors.txt

@@ -8,7 +8,6 @@ tests/cases/conformance/parser/ecmascript5/ErrorRecovery/ArrayLiteralExpressions
     var texCoords = [2, 2, 0.5000001192092895, 0.8749999 ; 403953552, 0.5000001192092895, 0.8749999403953552];
                                                          ~
 !!! error TS1005: ',' expected.
-!!! related TS1007 tests/cases/conformance/parser/ecmascript5/ErrorRecovery/ArrayLiteralExpressions/parserErrorRecoveryArrayLiteralExpression3.ts:1:17: The parser expected to find a ']' to match the '[' token here.
                                                            ~~~~~~~~~
 !!! error TS2695: Left side of comma operator is unused and has no side effects.
                                                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

tests/baselines/reference/parserFuzz1.errors.txt

@@ -20,5 +20,4 @@ tests/cases/conformance/parser/ecmascript5/ErrorRecovery/parserFuzz1.ts(2,15): e
         ~~~~~~
 !!! error TS1005: ';' expected.
 
-!!! error TS1005: '{' expected.
-!!! related TS1007 tests/cases/conformance/parser/ecmascript5/ErrorRecovery/parserFuzz1.ts:1:9: The parser expected to find a '}' to match the '{' token here.
+!!! error TS1005: '{' expected.