From 89497fcac9bc5fddda798f31c052695e84fa58da Mon Sep 17 00:00:00 2001
From: Andrew Branch <andrew@wheream.io>
Date: Wed, 24 Apr 2019 14:15:58 -0700
Subject: [PATCH] =?UTF-8?q?Don=E2=80=99t=20use=20checkExpressionCached=20w?=
 =?UTF-8?q?hen=20checking=20spread=20element=20inside=20a=20loop?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/compiler/checker.ts                       |  2 +-
 .../noImplicitAnyLoopCrash.errors.txt         | 18 ++++++++++++++++
 .../reference/noImplicitAnyLoopCrash.js       | 14 +++++++++++++
 .../reference/noImplicitAnyLoopCrash.symbols  | 14 +++++++++++++
 .../reference/noImplicitAnyLoopCrash.types    | 21 +++++++++++++++++++
 .../cases/compiler/noImplicitAnyLoopCrash.ts  |  9 ++++----
 6 files changed, 73 insertions(+), 5 deletions(-)
 create mode 100644 tests/baselines/reference/noImplicitAnyLoopCrash.errors.txt
 create mode 100644 tests/baselines/reference/noImplicitAnyLoopCrash.js
 create mode 100644 tests/baselines/reference/noImplicitAnyLoopCrash.symbols
 create mode 100644 tests/baselines/reference/noImplicitAnyLoopCrash.types

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 22a658a0f7ab3..d53253e655841 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -20708,7 +20708,7 @@ namespace ts {
                 // of the argument is a tuple type, spread the tuple elements into the argument list. We can
                 // call checkExpressionCached because spread expressions never have a contextual type.
                 const spreadArgument = <SpreadElement>args[length - 1];
-                const type = checkExpressionCached(spreadArgument.expression);
+                const type = flowLoopCount ? checkExpression(spreadArgument.expression) : checkExpressionCached(spreadArgument.expression);
                 if (isTupleType(type)) {
                     const typeArguments = (<TypeReference>type).typeArguments || emptyArray;
                     const restIndex = type.target.hasRestElement ? typeArguments.length - 1 : -1;
diff --git a/tests/baselines/reference/noImplicitAnyLoopCrash.errors.txt b/tests/baselines/reference/noImplicitAnyLoopCrash.errors.txt
new file mode 100644
index 0000000000000..2937f133749d7
--- /dev/null
+++ b/tests/baselines/reference/noImplicitAnyLoopCrash.errors.txt
@@ -0,0 +1,18 @@
+tests/cases/compiler/noImplicitAnyLoopCrash.ts(4,16): error TS2556: Expected 0 arguments, but got 1 or more.
+tests/cases/compiler/noImplicitAnyLoopCrash.ts(4,19): error TS2461: Type 'number' is not an array type.
+tests/cases/compiler/noImplicitAnyLoopCrash.ts(4,19): error TS2461: Type 'undefined' is not an array type.
+
+
+==== tests/cases/compiler/noImplicitAnyLoopCrash.ts (3 errors) ====
+    let foo = () => {};
+    let bar;
+    while (1) {
+        bar = ~foo(...bar);
+                   ~~~~~~
+!!! error TS2556: Expected 0 arguments, but got 1 or more.
+                      ~~~
+!!! error TS2461: Type 'number' is not an array type.
+                      ~~~
+!!! error TS2461: Type 'undefined' is not an array type.
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/noImplicitAnyLoopCrash.js b/tests/baselines/reference/noImplicitAnyLoopCrash.js
new file mode 100644
index 0000000000000..36f8a7470b221
--- /dev/null
+++ b/tests/baselines/reference/noImplicitAnyLoopCrash.js
@@ -0,0 +1,14 @@
+//// [noImplicitAnyLoopCrash.ts]
+let foo = () => {};
+let bar;
+while (1) {
+    bar = ~foo(...bar);
+}
+
+
+//// [noImplicitAnyLoopCrash.js]
+var foo = function () { };
+var bar;
+while (1) {
+    bar = ~foo.apply(void 0, bar);
+}
diff --git a/tests/baselines/reference/noImplicitAnyLoopCrash.symbols b/tests/baselines/reference/noImplicitAnyLoopCrash.symbols
new file mode 100644
index 0000000000000..1bac6fac5ab4b
--- /dev/null
+++ b/tests/baselines/reference/noImplicitAnyLoopCrash.symbols
@@ -0,0 +1,14 @@
+=== tests/cases/compiler/noImplicitAnyLoopCrash.ts ===
+let foo = () => {};
+>foo : Symbol(foo, Decl(noImplicitAnyLoopCrash.ts, 0, 3))
+
+let bar;
+>bar : Symbol(bar, Decl(noImplicitAnyLoopCrash.ts, 1, 3))
+
+while (1) {
+    bar = ~foo(...bar);
+>bar : Symbol(bar, Decl(noImplicitAnyLoopCrash.ts, 1, 3))
+>foo : Symbol(foo, Decl(noImplicitAnyLoopCrash.ts, 0, 3))
+>bar : Symbol(bar, Decl(noImplicitAnyLoopCrash.ts, 1, 3))
+}
+
diff --git a/tests/baselines/reference/noImplicitAnyLoopCrash.types b/tests/baselines/reference/noImplicitAnyLoopCrash.types
new file mode 100644
index 0000000000000..2e698c0673eba
--- /dev/null
+++ b/tests/baselines/reference/noImplicitAnyLoopCrash.types
@@ -0,0 +1,21 @@
+=== tests/cases/compiler/noImplicitAnyLoopCrash.ts ===
+let foo = () => {};
+>foo : () => void
+>() => {} : () => void
+
+let bar;
+>bar : any
+
+while (1) {
+>1 : 1
+
+    bar = ~foo(...bar);
+>bar = ~foo(...bar) : number
+>bar : any
+>~foo(...bar) : number
+>foo(...bar) : void
+>foo : () => void
+>...bar : any
+>bar : number
+}
+
diff --git a/tests/cases/compiler/noImplicitAnyLoopCrash.ts b/tests/cases/compiler/noImplicitAnyLoopCrash.ts
index d43802765065e..1df8a27a92df6 100644
--- a/tests/cases/compiler/noImplicitAnyLoopCrash.ts
+++ b/tests/cases/compiler/noImplicitAnyLoopCrash.ts
@@ -1,5 +1,6 @@
 // @noImplicitAny: true
-let foo = () => {};     // if you remove or change foo definition to not a function, bug disappears
-let bar;                // if you add type annotation here, bug disappears
-while (1)               // if you remove while, bug disappears
-    bar = ~foo(...bar); // if you remove unary or spread operator, bug disappears
\ No newline at end of file
+let foo = () => {};
+let bar;
+while (1) {
+    bar = ~foo(...bar);
+}