take token kind from the tree in case if token kind from scanner is different

src/services/formatting/formattingScanner.ts

@@ -146,7 +146,7 @@ module ts.formatting {
             if (lastTokenInfo && expectedScanAction === lastScanAction) {
                 // readTokenInfo was called before with the same expected scan action.
                 // No need to re-scan text, return existing 'lastTokenInfo'
-                return lastTokenInfo;
+                return fixTokenKind(lastTokenInfo, n);
             }
 
             if (scanner.getStartPos() !== savedPos) {
@@ -207,11 +207,13 @@ module ts.formatting {
                 }
             }
 
-            return lastTokenInfo = {
+            lastTokenInfo = {
                 leadingTrivia: leadingTrivia,
                 trailingTrivia: trailingTrivia,
                 token: token
             }
+
+            return fixTokenKind(lastTokenInfo, n);
         }
 
         function isOnToken(): boolean {
@@ -219,5 +221,16 @@ module ts.formatting {
             var startPos = (lastTokenInfo && lastTokenInfo.token.pos) || scanner.getStartPos();
             return startPos < endPos && current !== SyntaxKind.EndOfFileToken && !isTrivia(current);
         }
+
+        // when containing node in the tree is token 
+        // but its kind differs from the kind that was returned by the scanner,
+        // then kind needs to be fixed. This might happen in cases 
+        // when parser interprets token differently, i.e keyword treated as identifier
+        function fixTokenKind(tokenInfo: TokenInfo, container: Node): TokenInfo {
+            if (isToken(container) && tokenInfo.token.kind !== container.kind) {
+                tokenInfo.token.kind = container.kind;
+            }
+            return tokenInfo;
+        }
     }
 }

tests/cases/fourslash/formattingKeywordAsIdentifier.ts

@@ -0,0 +1,7 @@
+/// <reference path='fourslash.ts'/>
+
+////declare var module/*1*/
+
+goTo.marker("1");
+edit.insert(";");
+verify.currentLineContentIs("declare var module;");