From 561360d550de590129fd899452c15d2e5d081d9d Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Wed, 2 Dec 2015 10:23:49 -0800
Subject: [PATCH] Adding regression test

---
 .../reference/unionTypeParameterInference.js  | 14 ++++++++
 .../unionTypeParameterInference.symbols       | 33 ++++++++++++++++++
 .../unionTypeParameterInference.types         | 34 +++++++++++++++++++
 .../compiler/unionTypeParameterInference.ts   |  7 ++++
 4 files changed, 88 insertions(+)
 create mode 100644 tests/baselines/reference/unionTypeParameterInference.js
 create mode 100644 tests/baselines/reference/unionTypeParameterInference.symbols
 create mode 100644 tests/baselines/reference/unionTypeParameterInference.types
 create mode 100644 tests/cases/compiler/unionTypeParameterInference.ts

diff --git a/tests/baselines/reference/unionTypeParameterInference.js b/tests/baselines/reference/unionTypeParameterInference.js
new file mode 100644
index 00000000000..cc797c511c8
--- /dev/null
+++ b/tests/baselines/reference/unionTypeParameterInference.js
@@ -0,0 +1,14 @@
+//// [unionTypeParameterInference.ts]
+interface Foo<T> { prop: T; }
+
+declare function lift<U>(value: U | Foo<U>): Foo<U>;
+
+function unlift<U>(value: U | Foo<U>): U {
+    return lift(value).prop; // error TS2322: Type '{}' is not assignable to type 'U'.
+}
+
+
+//// [unionTypeParameterInference.js]
+function unlift(value) {
+    return lift(value).prop; // error TS2322: Type '{}' is not assignable to type 'U'.
+}
diff --git a/tests/baselines/reference/unionTypeParameterInference.symbols b/tests/baselines/reference/unionTypeParameterInference.symbols
new file mode 100644
index 00000000000..ee540379284
--- /dev/null
+++ b/tests/baselines/reference/unionTypeParameterInference.symbols
@@ -0,0 +1,33 @@
+=== tests/cases/compiler/unionTypeParameterInference.ts ===
+interface Foo<T> { prop: T; }
+>Foo : Symbol(Foo, Decl(unionTypeParameterInference.ts, 0, 0))
+>T : Symbol(T, Decl(unionTypeParameterInference.ts, 0, 14))
+>prop : Symbol(prop, Decl(unionTypeParameterInference.ts, 0, 18))
+>T : Symbol(T, Decl(unionTypeParameterInference.ts, 0, 14))
+
+declare function lift<U>(value: U | Foo<U>): Foo<U>;
+>lift : Symbol(lift, Decl(unionTypeParameterInference.ts, 0, 29))
+>U : Symbol(U, Decl(unionTypeParameterInference.ts, 2, 22))
+>value : Symbol(value, Decl(unionTypeParameterInference.ts, 2, 25))
+>U : Symbol(U, Decl(unionTypeParameterInference.ts, 2, 22))
+>Foo : Symbol(Foo, Decl(unionTypeParameterInference.ts, 0, 0))
+>U : Symbol(U, Decl(unionTypeParameterInference.ts, 2, 22))
+>Foo : Symbol(Foo, Decl(unionTypeParameterInference.ts, 0, 0))
+>U : Symbol(U, Decl(unionTypeParameterInference.ts, 2, 22))
+
+function unlift<U>(value: U | Foo<U>): U {
+>unlift : Symbol(unlift, Decl(unionTypeParameterInference.ts, 2, 52))
+>U : Symbol(U, Decl(unionTypeParameterInference.ts, 4, 16))
+>value : Symbol(value, Decl(unionTypeParameterInference.ts, 4, 19))
+>U : Symbol(U, Decl(unionTypeParameterInference.ts, 4, 16))
+>Foo : Symbol(Foo, Decl(unionTypeParameterInference.ts, 0, 0))
+>U : Symbol(U, Decl(unionTypeParameterInference.ts, 4, 16))
+>U : Symbol(U, Decl(unionTypeParameterInference.ts, 4, 16))
+
+    return lift(value).prop; // error TS2322: Type '{}' is not assignable to type 'U'.
+>lift(value).prop : Symbol(Foo.prop, Decl(unionTypeParameterInference.ts, 0, 18))
+>lift : Symbol(lift, Decl(unionTypeParameterInference.ts, 0, 29))
+>value : Symbol(value, Decl(unionTypeParameterInference.ts, 4, 19))
+>prop : Symbol(Foo.prop, Decl(unionTypeParameterInference.ts, 0, 18))
+}
+
diff --git a/tests/baselines/reference/unionTypeParameterInference.types b/tests/baselines/reference/unionTypeParameterInference.types
new file mode 100644
index 00000000000..a4b6a09cf2c
--- /dev/null
+++ b/tests/baselines/reference/unionTypeParameterInference.types
@@ -0,0 +1,34 @@
+=== tests/cases/compiler/unionTypeParameterInference.ts ===
+interface Foo<T> { prop: T; }
+>Foo : Foo<T>
+>T : T
+>prop : T
+>T : T
+
+declare function lift<U>(value: U | Foo<U>): Foo<U>;
+>lift : <U>(value: U | Foo<U>) => Foo<U>
+>U : U
+>value : U | Foo<U>
+>U : U
+>Foo : Foo<T>
+>U : U
+>Foo : Foo<T>
+>U : U
+
+function unlift<U>(value: U | Foo<U>): U {
+>unlift : <U>(value: U | Foo<U>) => U
+>U : U
+>value : U | Foo<U>
+>U : U
+>Foo : Foo<T>
+>U : U
+>U : U
+
+    return lift(value).prop; // error TS2322: Type '{}' is not assignable to type 'U'.
+>lift(value).prop : U
+>lift(value) : Foo<U>
+>lift : <U>(value: U | Foo<U>) => Foo<U>
+>value : U | Foo<U>
+>prop : U
+}
+
diff --git a/tests/cases/compiler/unionTypeParameterInference.ts b/tests/cases/compiler/unionTypeParameterInference.ts
new file mode 100644
index 00000000000..221b0891b98
--- /dev/null
+++ b/tests/cases/compiler/unionTypeParameterInference.ts
@@ -0,0 +1,7 @@
+interface Foo<T> { prop: T; }
+
+declare function lift<U>(value: U | Foo<U>): Foo<U>;
+
+function unlift<U>(value: U | Foo<U>): U {
+    return lift(value).prop; // error TS2322: Type '{}' is not assignable to type 'U'.
+}