do not indent leading comments that attached to tokens with errors

Author: vladima

src/services/formatting/formatting.ts

@@ -622,14 +622,21 @@ module ts.formatting {
 
                 var tokenStart = sourceFile.getLineAndCharacterFromPosition(currentTokenInfo.token.pos);
                 if (isTokenInRange) {
+                    var rangeHasError = rangeContainsError(currentTokenInfo.token);
                     // save prevStartLine since processRange will overwrite this value with current ones
                     var prevStartLine = previousRangeStartLine;
                     lineAdded = processRange(currentTokenInfo.token, tokenStart, parent, childContextNode, dynamicIndentation);
-                    if (lineAdded !== undefined) {
-                        indentToken = lineAdded;
+                    if (rangeHasError) {
+                        // do not indent comments\token if token range overlaps with some error
+                        indentToken = false;
                     }
                     else {
-                        indentToken = lastTriviaWasNewLine && tokenStart.line !== prevStartLine;
+                        if (lineAdded !== undefined) {
+                            indentToken = lineAdded;
+                        }
+                        else {
+                            indentToken = lastTriviaWasNewLine && tokenStart.line !== prevStartLine;
+                        }
                     }
                 }
 

tests/cases/fourslash/formattingCommentsBeforeErrors.ts

@@ -0,0 +1,20 @@
+/// <reference path='fourslash.ts' />
+
+////module A {
+////    interface B {
+////        // a
+////        // b
+////        baz();
+/////*0*/        // d /*1*/asd a
+////        // e
+////        foo();
+////        // f asd
+////        // g as
+////        bar();
+////    }
+////}
+
+goTo.marker("1");
+edit.insert("\n");
+goTo.marker("0");
+verify.currentLineContentIs("        // d ");