From 59e5bbc393d7b136fab0467f1e3e646df3eb68ea Mon Sep 17 00:00:00 2001
From: Mohamed Hegazy <mhegazy@microsoft.com>
Date: Fri, 1 Dec 2017 19:51:14 -0800
Subject: [PATCH] Make sure autoArrayType is unique, even if no lib is
 available (#20344)

* Make sure autoArrayType is unique, even if no lib is available

* fix typo
---
 src/compiler/checker.ts                       |  5 ++++
 .../reference/noCrashOnNoLib.errors.txt       | 25 +++++++++++++++++++
 tests/baselines/reference/noCrashOnNoLib.js   | 18 +++++++++++++
 .../reference/noCrashOnNoLib.symbols          | 13 ++++++++++
 .../baselines/reference/noCrashOnNoLib.types  | 21 ++++++++++++++++
 tests/cases/compiler/noCrashOnNoLib.ts        |  8 ++++++
 6 files changed, 90 insertions(+)
 create mode 100644 tests/baselines/reference/noCrashOnNoLib.errors.txt
 create mode 100644 tests/baselines/reference/noCrashOnNoLib.js
 create mode 100644 tests/baselines/reference/noCrashOnNoLib.symbols
 create mode 100644 tests/baselines/reference/noCrashOnNoLib.types
 create mode 100644 tests/cases/compiler/noCrashOnNoLib.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index c3def69c1e0..2ab67120e4b 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -25170,7 +25170,12 @@ namespace ts {
             globalBooleanType = getGlobalType("Boolean" as __String, /*arity*/ 0, /*reportErrors*/ true);
             globalRegExpType = getGlobalType("RegExp" as __String, /*arity*/ 0, /*reportErrors*/ true);
             anyArrayType = createArrayType(anyType);
+
             autoArrayType = createArrayType(autoType);
+            if (autoArrayType === emptyObjectType) {
+                // autoArrayType is used as a marker, so even if global Array type is not defined, it needs to be a unique type
+                autoArrayType = createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
+            }
 
             globalReadonlyArrayType = <GenericType>getGlobalTypeOrUndefined("ReadonlyArray" as __String, /*arity*/ 1);
             anyReadonlyArrayType = globalReadonlyArrayType ? createTypeFromGenericGlobalType(globalReadonlyArrayType, [anyType]) : anyArrayType;
diff --git a/tests/baselines/reference/noCrashOnNoLib.errors.txt b/tests/baselines/reference/noCrashOnNoLib.errors.txt
new file mode 100644
index 00000000000..50e51918522
--- /dev/null
+++ b/tests/baselines/reference/noCrashOnNoLib.errors.txt
@@ -0,0 +1,25 @@
+error TS2318: Cannot find global type 'Array'.
+error TS2318: Cannot find global type 'Boolean'.
+error TS2318: Cannot find global type 'Function'.
+error TS2318: Cannot find global type 'IArguments'.
+error TS2318: Cannot find global type 'Number'.
+error TS2318: Cannot find global type 'Object'.
+error TS2318: Cannot find global type 'RegExp'.
+error TS2318: Cannot find global type 'String'.
+
+
+!!! error TS2318: Cannot find global type 'Array'.
+!!! error TS2318: Cannot find global type 'Boolean'.
+!!! error TS2318: Cannot find global type 'Function'.
+!!! error TS2318: Cannot find global type 'IArguments'.
+!!! error TS2318: Cannot find global type 'Number'.
+!!! error TS2318: Cannot find global type 'Object'.
+!!! error TS2318: Cannot find global type 'RegExp'.
+!!! error TS2318: Cannot find global type 'String'.
+==== tests/cases/compiler/noCrashOnNoLib.ts (0 errors) ====
+    export function f() {
+        let e: {}[];
+        while (true) {
+          e = [...(e || [])];
+        }
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/noCrashOnNoLib.js b/tests/baselines/reference/noCrashOnNoLib.js
new file mode 100644
index 00000000000..715050103fb
--- /dev/null
+++ b/tests/baselines/reference/noCrashOnNoLib.js
@@ -0,0 +1,18 @@
+//// [noCrashOnNoLib.ts]
+export function f() {
+    let e: {}[];
+    while (true) {
+      e = [...(e || [])];
+    }
+}
+
+//// [noCrashOnNoLib.js]
+"use strict";
+exports.__esModule = true;
+function f() {
+    var e;
+    while (true) {
+        e = (e || []).slice();
+    }
+}
+exports.f = f;
diff --git a/tests/baselines/reference/noCrashOnNoLib.symbols b/tests/baselines/reference/noCrashOnNoLib.symbols
new file mode 100644
index 00000000000..ee36c90dc0f
--- /dev/null
+++ b/tests/baselines/reference/noCrashOnNoLib.symbols
@@ -0,0 +1,13 @@
+=== tests/cases/compiler/noCrashOnNoLib.ts ===
+export function f() {
+>f : Symbol(f, Decl(noCrashOnNoLib.ts, 0, 0))
+
+    let e: {}[];
+>e : Symbol(e, Decl(noCrashOnNoLib.ts, 1, 7))
+
+    while (true) {
+      e = [...(e || [])];
+>e : Symbol(e, Decl(noCrashOnNoLib.ts, 1, 7))
+>e : Symbol(e, Decl(noCrashOnNoLib.ts, 1, 7))
+    }
+}
diff --git a/tests/baselines/reference/noCrashOnNoLib.types b/tests/baselines/reference/noCrashOnNoLib.types
new file mode 100644
index 00000000000..384f34dc359
--- /dev/null
+++ b/tests/baselines/reference/noCrashOnNoLib.types
@@ -0,0 +1,21 @@
+=== tests/cases/compiler/noCrashOnNoLib.ts ===
+export function f() {
+>f : () => void
+
+    let e: {}[];
+>e : {}
+
+    while (true) {
+>true : true
+
+      e = [...(e || [])];
+>e = [...(e || [])] : {}
+>e : {}
+>[...(e || [])] : {}
+>...(e || []) : any
+>(e || []) : {}
+>e || [] : {}
+>e : {}
+>[] : {}
+    }
+}
diff --git a/tests/cases/compiler/noCrashOnNoLib.ts b/tests/cases/compiler/noCrashOnNoLib.ts
new file mode 100644
index 00000000000..c4cb3f19359
--- /dev/null
+++ b/tests/cases/compiler/noCrashOnNoLib.ts
@@ -0,0 +1,8 @@
+// @noLib: true
+
+export function f() {
+    let e: {}[];
+    while (true) {
+      e = [...(e || [])];
+    }
+}
\ No newline at end of file