From 615050437b453d6458fdaf402a49088da57c27e1 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Wed, 24 Feb 2021 09:52:18 -0800
Subject: [PATCH] Add regression test

---
 .../reference/unionOfEnumInference.js         | 29 ++++++++++++
 .../reference/unionOfEnumInference.symbols    | 44 +++++++++++++++++++
 .../reference/unionOfEnumInference.types      | 31 +++++++++++++
 tests/cases/compiler/unionOfEnumInference.ts  | 15 +++++++
 4 files changed, 119 insertions(+)
 create mode 100644 tests/baselines/reference/unionOfEnumInference.js
 create mode 100644 tests/baselines/reference/unionOfEnumInference.symbols
 create mode 100644 tests/baselines/reference/unionOfEnumInference.types
 create mode 100644 tests/cases/compiler/unionOfEnumInference.ts

diff --git a/tests/baselines/reference/unionOfEnumInference.js b/tests/baselines/reference/unionOfEnumInference.js
new file mode 100644
index 0000000000000..b0afc9fe2f02e
--- /dev/null
+++ b/tests/baselines/reference/unionOfEnumInference.js
@@ -0,0 +1,29 @@
+//// [unionOfEnumInference.ts]
+// Repro from #42932
+
+enum Enum { A, B, C }
+
+interface Interface<T extends Enum> {
+	type: T;
+}
+
+function foo<T extends Enum>(x: Interface<T>) { }
+
+function bar(x: Interface<Enum.A | Enum.B> | Interface<Enum.C>) {
+	foo(x);
+}
+
+
+//// [unionOfEnumInference.js]
+"use strict";
+// Repro from #42932
+var Enum;
+(function (Enum) {
+    Enum[Enum["A"] = 0] = "A";
+    Enum[Enum["B"] = 1] = "B";
+    Enum[Enum["C"] = 2] = "C";
+})(Enum || (Enum = {}));
+function foo(x) { }
+function bar(x) {
+    foo(x);
+}
diff --git a/tests/baselines/reference/unionOfEnumInference.symbols b/tests/baselines/reference/unionOfEnumInference.symbols
new file mode 100644
index 0000000000000..a3ec42d2a505a
--- /dev/null
+++ b/tests/baselines/reference/unionOfEnumInference.symbols
@@ -0,0 +1,44 @@
+=== tests/cases/compiler/unionOfEnumInference.ts ===
+// Repro from #42932
+
+enum Enum { A, B, C }
+>Enum : Symbol(Enum, Decl(unionOfEnumInference.ts, 0, 0))
+>A : Symbol(Enum.A, Decl(unionOfEnumInference.ts, 2, 11))
+>B : Symbol(Enum.B, Decl(unionOfEnumInference.ts, 2, 14))
+>C : Symbol(Enum.C, Decl(unionOfEnumInference.ts, 2, 17))
+
+interface Interface<T extends Enum> {
+>Interface : Symbol(Interface, Decl(unionOfEnumInference.ts, 2, 21))
+>T : Symbol(T, Decl(unionOfEnumInference.ts, 4, 20))
+>Enum : Symbol(Enum, Decl(unionOfEnumInference.ts, 0, 0))
+
+	type: T;
+>type : Symbol(Interface.type, Decl(unionOfEnumInference.ts, 4, 37))
+>T : Symbol(T, Decl(unionOfEnumInference.ts, 4, 20))
+}
+
+function foo<T extends Enum>(x: Interface<T>) { }
+>foo : Symbol(foo, Decl(unionOfEnumInference.ts, 6, 1))
+>T : Symbol(T, Decl(unionOfEnumInference.ts, 8, 13))
+>Enum : Symbol(Enum, Decl(unionOfEnumInference.ts, 0, 0))
+>x : Symbol(x, Decl(unionOfEnumInference.ts, 8, 29))
+>Interface : Symbol(Interface, Decl(unionOfEnumInference.ts, 2, 21))
+>T : Symbol(T, Decl(unionOfEnumInference.ts, 8, 13))
+
+function bar(x: Interface<Enum.A | Enum.B> | Interface<Enum.C>) {
+>bar : Symbol(bar, Decl(unionOfEnumInference.ts, 8, 49))
+>x : Symbol(x, Decl(unionOfEnumInference.ts, 10, 13))
+>Interface : Symbol(Interface, Decl(unionOfEnumInference.ts, 2, 21))
+>Enum : Symbol(Enum, Decl(unionOfEnumInference.ts, 0, 0))
+>A : Symbol(Enum.A, Decl(unionOfEnumInference.ts, 2, 11))
+>Enum : Symbol(Enum, Decl(unionOfEnumInference.ts, 0, 0))
+>B : Symbol(Enum.B, Decl(unionOfEnumInference.ts, 2, 14))
+>Interface : Symbol(Interface, Decl(unionOfEnumInference.ts, 2, 21))
+>Enum : Symbol(Enum, Decl(unionOfEnumInference.ts, 0, 0))
+>C : Symbol(Enum.C, Decl(unionOfEnumInference.ts, 2, 17))
+
+	foo(x);
+>foo : Symbol(foo, Decl(unionOfEnumInference.ts, 6, 1))
+>x : Symbol(x, Decl(unionOfEnumInference.ts, 10, 13))
+}
+
diff --git a/tests/baselines/reference/unionOfEnumInference.types b/tests/baselines/reference/unionOfEnumInference.types
new file mode 100644
index 0000000000000..739f431b55393
--- /dev/null
+++ b/tests/baselines/reference/unionOfEnumInference.types
@@ -0,0 +1,31 @@
+=== tests/cases/compiler/unionOfEnumInference.ts ===
+// Repro from #42932
+
+enum Enum { A, B, C }
+>Enum : Enum
+>A : Enum.A
+>B : Enum.B
+>C : Enum.C
+
+interface Interface<T extends Enum> {
+	type: T;
+>type : T
+}
+
+function foo<T extends Enum>(x: Interface<T>) { }
+>foo : <T extends Enum>(x: Interface<T>) => void
+>x : Interface<T>
+
+function bar(x: Interface<Enum.A | Enum.B> | Interface<Enum.C>) {
+>bar : (x: Interface<Enum.A | Enum.B> | Interface<Enum.C>) => void
+>x : Interface<Enum.A | Enum.B> | Interface<Enum.C>
+>Enum : any
+>Enum : any
+>Enum : any
+
+	foo(x);
+>foo(x) : void
+>foo : <T extends Enum>(x: Interface<T>) => void
+>x : Interface<Enum.A | Enum.B> | Interface<Enum.C>
+}
+
diff --git a/tests/cases/compiler/unionOfEnumInference.ts b/tests/cases/compiler/unionOfEnumInference.ts
new file mode 100644
index 0000000000000..26f92804834bd
--- /dev/null
+++ b/tests/cases/compiler/unionOfEnumInference.ts
@@ -0,0 +1,15 @@
+// @strict: true
+
+// Repro from #42932
+
+enum Enum { A, B, C }
+
+interface Interface<T extends Enum> {
+	type: T;
+}
+
+function foo<T extends Enum>(x: Interface<T>) { }
+
+function bar(x: Interface<Enum.A | Enum.B> | Interface<Enum.C>) {
+	foo(x);
+}