From 1773ca74578b44200ff754534299a7fd1962adbd Mon Sep 17 00:00:00 2001
From: Andy <anhans@microsoft.com>
Date: Wed, 10 May 2017 12:55:09 -0700
Subject: [PATCH] Type-check State (#492)

---
 src/parser/comments.js |  2 +-
 src/tokenizer/index.js |  1 +
 src/tokenizer/state.js | 42 +++++++++++++++++++++++++++++-------------
 3 files changed, 31 insertions(+), 14 deletions(-)

diff --git a/src/parser/comments.js b/src/parser/comments.js
index c39f91e44a..96e339389b 100644
--- a/src/parser/comments.js
+++ b/src/parser/comments.js
@@ -29,7 +29,7 @@
 import BaseParser from "./base";
 import type { Comment, Node } from "../types";
 
-function last(stack) {
+function last<T>(stack: $ReadOnlyArray<T>): T {
   return stack[stack.length - 1];
 }
 
diff --git a/src/tokenizer/index.js b/src/tokenizer/index.js
index 34f75fa490..42273d664c 100644
--- a/src/tokenizer/index.js
+++ b/src/tokenizer/index.js
@@ -626,6 +626,7 @@ export default class Tokenizer extends LocationParser {
       code = this.readHexChar(this.input.indexOf("}", this.state.pos) - this.state.pos, throwOnInvalid);
       ++this.state.pos;
       if (code === null) {
+        // $FlowFixMe (is this always non-null?)
         --this.state.invalidTemplateEscapePosition; // to point to the '\'' instead of the 'u'
       } else if (code > 0x10FFFF) {
         if (throwOnInvalid) {
diff --git a/src/tokenizer/state.js b/src/tokenizer/state.js
index 1bbfbda23d..3200c4e646 100644
--- a/src/tokenizer/state.js
+++ b/src/tokenizer/state.js
@@ -1,11 +1,17 @@
+// @flow
+
+import type { Options } from "../options";
+import * as N from "../types";
+
 import type { TokContext } from "./context";
+import type { Token } from "./index";
 import type { TokenType } from "./types";
 import { Position } from "../util/location";
 import { types as ct } from "./context";
 import { types as tt } from "./types";
 
 export default class State {
-  init(options: Object, input: string) {
+  init(options: Options, input: string): void {
     this.strict = options.strictMode === false ? false : options.sourceType === "module";
 
     this.input = input;
@@ -70,28 +76,34 @@ export default class State {
   // Flags to track whether we are in a function, a generator.
   inFunction: boolean;
   inGenerator: boolean;
-  inMethod: boolean;
+  inMethod: boolean | N.MethodKind;
   inAsync: boolean;
   inType: boolean;
+  noAnonFunctionType: boolean;
   inPropertyName: boolean;
   inClassProperty: boolean;
 
   // Labels in scope.
-  labels: Array<Object>;
+  labels: Array<{ kind: ?("loop" | "switch"), statementStart?: number }>;
 
   // Leading decorators.
-  decorators: Array<Object>;
+  decorators: Array<N.Decorator>;
 
   // Token store.
-  tokens: Array<Object>;
+  tokens: Array<Token | N.Comment>;
 
   // Comment store.
-  comments: Array<Object>;
+  comments: Array<N.Comment>;
 
   // Comment attachment store
-  trailingComments: Array<Object>;
-  leadingComments: Array<Object>;
-  commentStack: Array<Object>;
+  trailingComments: Array<N.Comment>;
+  leadingComments: Array<N.Comment>;
+  commentStack: Array<{
+    start: number;
+    leadingComments: ?Array<N.Comment>;
+    trailingComments: ?Array<N.Comment>;
+  }>;
+  commentPreviousNode: N.Node;
 
   // The current position of the tokenizer in the input.
   pos: number;
@@ -115,8 +127,8 @@ export default class State {
   endLoc: Position;
 
   // Position information for the previous token
-  lastTokEndLoc: ?Position;
-  lastTokStartLoc: ?Position;
+  lastTokEndLoc: Position;
+  lastTokStartLoc: Position;
   lastTokStart: number;
   lastTokEnd: number;
 
@@ -139,19 +151,23 @@ export default class State {
   // `export default foo;` and `export { foo as default };`.
   exportedIdentifiers: Array<string>;
 
-  curPosition() {
+  invalidTemplateEscapePosition: ?number;
+
+  curPosition(): Position {
     return new Position(this.curLine, this.pos - this.lineStart);
   }
 
-  clone(skipArrays?) {
+  clone(skipArrays?: boolean): State {
     const state = new State;
     for (const key in this) {
+      // $FlowIgnore
       let val = this[key];
 
       if ((!skipArrays || key === "context") && Array.isArray(val)) {
         val = val.slice();
       }
 
+      // $FlowIgnore
       state[key] = val;
     }
     return state;