From b55b6e2f6b69798ace74b28122931ac302f41870 Mon Sep 17 00:00:00 2001
From: Klaus Meinhardt <klaus.meinhardt1@gmail.com>
Date: Mon, 12 Nov 2018 21:45:36 +0100
Subject: [PATCH] fix comment parsing at start of file

* skip shebang if present (fixes: #28477)
* don't parse trailing comments as they are also treated like leading comments
---
 src/compiler/scanner.ts                       | 12 ++++-
 src/testRunner/tsconfig.json                  |  1 +
 src/testRunner/unittests/comments.ts          | 49 +++++++++++++++++++
 .../exponentiationOperatorSyntaxError1.js     |  3 +-
 .../reference/shebangBeforeReferences.js      |  1 +
 5 files changed, 63 insertions(+), 3 deletions(-)
 create mode 100644 src/testRunner/unittests/comments.ts

diff --git a/src/compiler/scanner.ts b/src/compiler/scanner.ts
index b8d4d248077..65e9d359836 100644
--- a/src/compiler/scanner.ts
+++ b/src/compiler/scanner.ts
@@ -642,8 +642,18 @@ namespace ts {
         let pendingKind!: CommentKind;
         let pendingHasTrailingNewLine!: boolean;
         let hasPendingCommentRange = false;
-        let collecting = trailing || pos === 0;
+        let collecting = trailing;
         let accumulator = initial;
+        if (pos === 0) {
+            if (collecting) {
+                return accumulator;
+            }
+            collecting = true;
+            const shebang = getShebang(text);
+            if (shebang) {
+                pos = shebang.length;
+            }
+        }
         scan: while (pos >= 0 && pos < text.length) {
             const ch = text.charCodeAt(pos);
             switch (ch) {
diff --git a/src/testRunner/tsconfig.json b/src/testRunner/tsconfig.json
index 32772ed311b..7f164df95c4 100644
--- a/src/testRunner/tsconfig.json
+++ b/src/testRunner/tsconfig.json
@@ -45,6 +45,7 @@
         "unittests/builder.ts",
         "unittests/cancellableLanguageServiceOperations.ts",
         "unittests/commandLineParsing.ts",
+        "unittests/comments.ts",
         "unittests/compileOnSave.ts",
         "unittests/compilerCore.ts",
         "unittests/configurationExtension.ts",
diff --git a/src/testRunner/unittests/comments.ts b/src/testRunner/unittests/comments.ts
new file mode 100644
index 00000000000..60ae4afd312
--- /dev/null
+++ b/src/testRunner/unittests/comments.ts
@@ -0,0 +1,49 @@
+namespace ts {
+    describe("comment parsing", () => {
+        const withShebang = `#! node
+/** comment */
+// another one
+;`;
+        const noShebang = `/** comment */
+// another one
+;`;
+        const withTrailing = `;/* comment */
+// another one
+`
+        it("skips shebang", () => {
+            const result = getLeadingCommentRanges(withShebang, 0);
+            assert.isDefined(result);
+            assert.strictEqual(result!.length, 2);
+        });
+
+        it("treats all comments at start of file as leading comments", () => {
+            const result = getLeadingCommentRanges(noShebang, 0);
+            assert.isDefined(result);
+            assert.strictEqual(result!.length, 2);
+        });
+
+        it("returns leading comments if position is not 0", () => {
+            const result = getLeadingCommentRanges(withTrailing, 1);
+            assert.isDefined(result);
+            assert.strictEqual(result!.length, 1);
+            assert.strictEqual(result![0].kind, SyntaxKind.SingleLineCommentTrivia);
+        });
+
+        it("returns no trailing comments at start of file", () => {
+            const result = getTrailingCommentRanges(noShebang, 0);
+            assert.isUndefined(result);
+        });
+
+        it("returns no trailing comments at start of file if shebang is present", () => {
+            const result = getTrailingCommentRanges(withShebang, 0);
+            assert.isUndefined(result);
+        });
+
+        it("returns trailing comments if position is not 0", () => {
+            const result = getTrailingCommentRanges(withTrailing, 1);
+            assert.isDefined(result);
+            assert.strictEqual(result!.length, 1);
+            assert.strictEqual(result![0].kind, SyntaxKind.MultiLineCommentTrivia);
+        });
+    });
+}
diff --git a/tests/baselines/reference/exponentiationOperatorSyntaxError1.js b/tests/baselines/reference/exponentiationOperatorSyntaxError1.js
index 667abed731c..bddd4880ee2 100644
--- a/tests/baselines/reference/exponentiationOperatorSyntaxError1.js
+++ b/tests/baselines/reference/exponentiationOperatorSyntaxError1.js
@@ -40,8 +40,7 @@ var temp = 10;
 
 //// [exponentiationOperatorSyntaxError1.js]
 // Error: early syntax error using ES7 SimpleUnaryExpression on left-hand side without ()
-Math.pow(// Error: early syntax error using ES7 SimpleUnaryExpression on left-hand side without ()
--1, 2);
+Math.pow(-1, 2);
 Math.pow(+1, 2);
 Math.pow(1, Math.pow(-2, 3));
 Math.pow(1, Math.pow(-2, -3));
diff --git a/tests/baselines/reference/shebangBeforeReferences.js b/tests/baselines/reference/shebangBeforeReferences.js
index 4ebf692e1d5..30e4b7a8633 100644
--- a/tests/baselines/reference/shebangBeforeReferences.js
+++ b/tests/baselines/reference/shebangBeforeReferences.js
@@ -17,6 +17,7 @@ use(x);
 //// [f.js]
 #!/usr/bin/env node
 "use strict";
+/// <reference path="f.d.ts"/>
 exports.__esModule = true;
 var test_1 = require("test");
 use(test_1.x);