Fix formatting scanner on JSX text that looks like trivia (microsoft#39718)

* Fix formatting scanner on JSX text that looks like trivia

* Combine if statements

Co-authored-by: Andrew Branch <andrew@wheream.io>

Author: Orta Therox

src/compiler/utilities.ts

@@ -483,7 +483,8 @@ namespace ts {
             return node.pos;
         }
 
-        if (isJSDocNode(node)) {
+        if (isJSDocNode(node) || node.kind === SyntaxKind.JsxText) {
+            // JsxText cannot actually contain comments, even though the scanner will think it sees comments
             return skipTrivia((sourceFile || getSourceFileOfNode(node)).text, node.pos, /*stopAfterLineBreak*/ false, /*stopAtComments*/ true);
         }
 

src/services/formatting/formatting.ts

@@ -720,6 +720,9 @@ namespace ts.formatting {
                     // proceed any parent tokens that are located prior to child.getStart()
                     const tokenInfo = formattingScanner.readTokenInfo(node);
                     if (tokenInfo.token.end > childStartPos) {
+                        if (tokenInfo.token.pos > childStartPos) {
+                            formattingScanner.skipToStartOf(child);
+                        }
                         // stop when formatting scanner advances past the beginning of the child
                         break;
                     }
@@ -731,13 +734,15 @@ namespace ts.formatting {
                     return inheritedIndentation;
                 }
 
-                // JSX text shouldn't affect indenting
-                if (isToken(child) && child.kind !== SyntaxKind.JsxText) {
+                if (isToken(child)) {
                     // if child node is a token, it does not impact indentation, proceed it using parent indentation scope rules
                     const tokenInfo = formattingScanner.readTokenInfo(child);
-                    Debug.assert(tokenInfo.token.end === child.end, "Token end is child end");
-                    consumeTokenAndAdvanceScanner(tokenInfo, node, parentDynamicIndentation, child);
-                    return inheritedIndentation;
+                    // JSX text shouldn't affect indenting
+                    if (child.kind !== SyntaxKind.JsxText) {
+                        Debug.assert(tokenInfo.token.end === child.end, "Token end is child end");
+                        consumeTokenAndAdvanceScanner(tokenInfo, node, parentDynamicIndentation, child);
+                        return inheritedIndentation;
+                    }
                 }
 
                 const effectiveParentStartLine = child.kind === SyntaxKind.Decorator ? childStartLine : undecoratedParentStartLine;

src/services/formatting/formattingScanner.ts

@@ -12,6 +12,7 @@ namespace ts.formatting {
         getCurrentLeadingTrivia(): TextRangeWithKind[] | undefined;
         lastTrailingTriviaWasNewLine(): boolean;
         skipToEndOf(node: Node): void;
+        skipToStartOf(node: Node): void;
     }
 
     const enum ScanAction {
@@ -47,6 +48,7 @@ namespace ts.formatting {
             getCurrentLeadingTrivia: () => leadingTrivia,
             lastTrailingTriviaWasNewLine: () => wasNewLine,
             skipToEndOf,
+            skipToStartOf,
         });
 
         lastTokenInfo = undefined;
@@ -298,5 +300,15 @@ namespace ts.formatting {
             leadingTrivia = undefined;
             trailingTrivia = undefined;
         }
+
+        function skipToStartOf(node: Node): void {
+            scanner.setTextPos(node.pos);
+            savedPos = scanner.getStartPos();
+            lastScanAction = undefined;
+            lastTokenInfo = undefined;
+            wasNewLine = false;
+            leadingTrivia = undefined;
+            trailingTrivia = undefined;
+        }
     }
 }

tests/cases/fourslash/formatTSXWithInlineComment.ts

@@ -0,0 +1,10 @@
+/// <reference path="fourslash.ts"/>
+// @Filename: foo.tsx
+////const a = <div>
+////    // <a />
+////</div>
+
+format.document();
+verify.currentFileContentIs(`const a = <div>
+    // <a />
+</div>`);