From df826de042f6e18102e44d625bfcba6df111e60a Mon Sep 17 00:00:00 2001
From: Jason Freeman <jfreeman@microsoft.com>
Date: Thu, 5 Feb 2015 12:30:22 -0800
Subject: [PATCH] symbols in type guards

---
 src/compiler/checker.ts                       |  2 +-
 tests/baselines/reference/symbolType17.js     | 21 ++++++++++++++++
 tests/baselines/reference/symbolType17.types  | 24 +++++++++++++++++++
 tests/baselines/reference/symbolType18.js     | 21 ++++++++++++++++
 tests/baselines/reference/symbolType18.types  | 24 +++++++++++++++++++
 tests/baselines/reference/symbolType19.js     | 24 +++++++++++++++++++
 tests/baselines/reference/symbolType19.types  | 23 ++++++++++++++++++
 .../conformance/es6/Symbols/symbolType17.ts   | 11 +++++++++
 .../conformance/es6/Symbols/symbolType18.ts   | 11 +++++++++
 .../conformance/es6/Symbols/symbolType19.ts   | 11 +++++++++
 10 files changed, 171 insertions(+), 1 deletion(-)
 create mode 100644 tests/baselines/reference/symbolType17.js
 create mode 100644 tests/baselines/reference/symbolType17.types
 create mode 100644 tests/baselines/reference/symbolType18.js
 create mode 100644 tests/baselines/reference/symbolType18.types
 create mode 100644 tests/baselines/reference/symbolType19.js
 create mode 100644 tests/baselines/reference/symbolType19.types
 create mode 100644 tests/cases/conformance/es6/Symbols/symbolType17.ts
 create mode 100644 tests/cases/conformance/es6/Symbols/symbolType18.ts
 create mode 100644 tests/cases/conformance/es6/Symbols/symbolType19.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index b40acf0ea06..17d79081974 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -4767,7 +4767,7 @@ module ts {
                 if (assumeTrue) {
                     // Assumed result is true. If check was not for a primitive type, remove all primitive types
                     if (!typeInfo) {
-                        return removeTypesFromUnionType(type, /*typeKind*/ TypeFlags.StringLike | TypeFlags.NumberLike | TypeFlags.Boolean, /*isOfTypeKind*/ true);
+                        return removeTypesFromUnionType(type, /*typeKind*/ TypeFlags.StringLike | TypeFlags.NumberLike | TypeFlags.Boolean | TypeFlags.ESSymbol, /*isOfTypeKind*/ true);
                     }
                     // Check was for a primitive type, return that primitive type if it is a subtype
                     if (isTypeSubtypeOf(typeInfo.type, type)) {
diff --git a/tests/baselines/reference/symbolType17.js b/tests/baselines/reference/symbolType17.js
new file mode 100644
index 00000000000..a00d2cb36f7
--- /dev/null
+++ b/tests/baselines/reference/symbolType17.js
@@ -0,0 +1,21 @@
+//// [symbolType17.ts]
+interface Foo { prop }
+var x: symbol | Foo;
+
+x;
+if (typeof x === "symbol") {
+    x;
+}
+else {
+    x;
+}
+
+//// [symbolType17.js]
+var x;
+x;
+if (typeof x === "symbol") {
+    x;
+}
+else {
+    x;
+}
diff --git a/tests/baselines/reference/symbolType17.types b/tests/baselines/reference/symbolType17.types
new file mode 100644
index 00000000000..b86d5a70ff7
--- /dev/null
+++ b/tests/baselines/reference/symbolType17.types
@@ -0,0 +1,24 @@
+=== tests/cases/conformance/es6/Symbols/symbolType17.ts ===
+interface Foo { prop }
+>Foo : Foo
+>prop : any
+
+var x: symbol | Foo;
+>x : symbol | Foo
+>Foo : Foo
+
+x;
+>x : symbol | Foo
+
+if (typeof x === "symbol") {
+>typeof x === "symbol" : boolean
+>typeof x : string
+>x : symbol | Foo
+
+    x;
+>x : symbol
+}
+else {
+    x;
+>x : Foo
+}
diff --git a/tests/baselines/reference/symbolType18.js b/tests/baselines/reference/symbolType18.js
new file mode 100644
index 00000000000..f8a784d2500
--- /dev/null
+++ b/tests/baselines/reference/symbolType18.js
@@ -0,0 +1,21 @@
+//// [symbolType18.ts]
+interface Foo { prop }
+var x: symbol | Foo;
+
+x;
+if (typeof x === "object") {
+    x;
+}
+else {
+    x;
+}
+
+//// [symbolType18.js]
+var x;
+x;
+if (typeof x === "object") {
+    x;
+}
+else {
+    x;
+}
diff --git a/tests/baselines/reference/symbolType18.types b/tests/baselines/reference/symbolType18.types
new file mode 100644
index 00000000000..1693c6e2499
--- /dev/null
+++ b/tests/baselines/reference/symbolType18.types
@@ -0,0 +1,24 @@
+=== tests/cases/conformance/es6/Symbols/symbolType18.ts ===
+interface Foo { prop }
+>Foo : Foo
+>prop : any
+
+var x: symbol | Foo;
+>x : symbol | Foo
+>Foo : Foo
+
+x;
+>x : symbol | Foo
+
+if (typeof x === "object") {
+>typeof x === "object" : boolean
+>typeof x : string
+>x : symbol | Foo
+
+    x;
+>x : Foo
+}
+else {
+    x;
+>x : symbol | Foo
+}
diff --git a/tests/baselines/reference/symbolType19.js b/tests/baselines/reference/symbolType19.js
new file mode 100644
index 00000000000..f3ba0e12472
--- /dev/null
+++ b/tests/baselines/reference/symbolType19.js
@@ -0,0 +1,24 @@
+//// [symbolType19.ts]
+enum E { }
+var x: symbol | E;
+
+x;
+if (typeof x === "number") {
+    x;
+}
+else {
+    x;
+}
+
+//// [symbolType19.js]
+var E;
+(function (E) {
+})(E || (E = {}));
+var x;
+x;
+if (typeof x === "number") {
+    x;
+}
+else {
+    x;
+}
diff --git a/tests/baselines/reference/symbolType19.types b/tests/baselines/reference/symbolType19.types
new file mode 100644
index 00000000000..d01fbfa87fe
--- /dev/null
+++ b/tests/baselines/reference/symbolType19.types
@@ -0,0 +1,23 @@
+=== tests/cases/conformance/es6/Symbols/symbolType19.ts ===
+enum E { }
+>E : E
+
+var x: symbol | E;
+>x : symbol | E
+>E : E
+
+x;
+>x : symbol | E
+
+if (typeof x === "number") {
+>typeof x === "number" : boolean
+>typeof x : string
+>x : symbol | E
+
+    x;
+>x : E
+}
+else {
+    x;
+>x : symbol
+}
diff --git a/tests/cases/conformance/es6/Symbols/symbolType17.ts b/tests/cases/conformance/es6/Symbols/symbolType17.ts
new file mode 100644
index 00000000000..95824f1794b
--- /dev/null
+++ b/tests/cases/conformance/es6/Symbols/symbolType17.ts
@@ -0,0 +1,11 @@
+//@target: ES6
+interface Foo { prop }
+var x: symbol | Foo;
+
+x;
+if (typeof x === "symbol") {
+    x;
+}
+else {
+    x;
+}
\ No newline at end of file
diff --git a/tests/cases/conformance/es6/Symbols/symbolType18.ts b/tests/cases/conformance/es6/Symbols/symbolType18.ts
new file mode 100644
index 00000000000..caa84171737
--- /dev/null
+++ b/tests/cases/conformance/es6/Symbols/symbolType18.ts
@@ -0,0 +1,11 @@
+//@target: ES6
+interface Foo { prop }
+var x: symbol | Foo;
+
+x;
+if (typeof x === "object") {
+    x;
+}
+else {
+    x;
+}
\ No newline at end of file
diff --git a/tests/cases/conformance/es6/Symbols/symbolType19.ts b/tests/cases/conformance/es6/Symbols/symbolType19.ts
new file mode 100644
index 00000000000..85d13b2cbdd
--- /dev/null
+++ b/tests/cases/conformance/es6/Symbols/symbolType19.ts
@@ -0,0 +1,11 @@
+//@target: ES6
+enum E { }
+var x: symbol | E;
+
+x;
+if (typeof x === "number") {
+    x;
+}
+else {
+    x;
+}
\ No newline at end of file