From 1191e2e7319ee2ac33a5e2d367388862eb10c673 Mon Sep 17 00:00:00 2001
From: Tiago Tristao <tiago.v.tristao@gmail.com>
Date: Mon, 5 Oct 2020 21:21:38 +0100
Subject: [PATCH] Fix class expression from being assignable if types don't
 match (#40660)

* Fix class expression from being assignable if types don't match

* Fix class expression from being assignable if types don't match
---
 src/compiler/checker.ts                          |  2 +-
 .../classExpressionAssignment.errors.txt         | 16 ++++++++++++++++
 .../reference/classExpressionAssignment.js       | 16 ++++++++++++++++
 .../reference/classExpressionAssignment.symbols  | 13 +++++++++++++
 .../reference/classExpressionAssignment.types    | 11 +++++++++++
 .../cases/compiler/classExpressionAssignment.ts  |  6 ++++++
 6 files changed, 63 insertions(+), 1 deletion(-)
 create mode 100644 tests/baselines/reference/classExpressionAssignment.errors.txt
 create mode 100644 tests/baselines/reference/classExpressionAssignment.js
 create mode 100644 tests/baselines/reference/classExpressionAssignment.symbols
 create mode 100644 tests/baselines/reference/classExpressionAssignment.types
 create mode 100644 tests/cases/compiler/classExpressionAssignment.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index cb1e2bf2f5c..8d4bec287a9 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -28180,7 +28180,7 @@ namespace ts {
             let name: Expression | BindingName | undefined;
             let decl: Node | undefined;
             if (isVariableDeclaration(node.parent) && node.parent.initializer === node) {
-                if (!isInJSFile(node) && !isVarConst(node.parent)) {
+                if (!isInJSFile(node) && !(isVarConst(node.parent) && isFunctionLikeDeclaration(node))) {
                     return undefined;
                 }
                 name = node.parent.name;
diff --git a/tests/baselines/reference/classExpressionAssignment.errors.txt b/tests/baselines/reference/classExpressionAssignment.errors.txt
new file mode 100644
index 00000000000..2519e23b441
--- /dev/null
+++ b/tests/baselines/reference/classExpressionAssignment.errors.txt
@@ -0,0 +1,16 @@
+tests/cases/compiler/classExpressionAssignment.ts(6,7): error TS2322: Type 'typeof A' is not assignable to type 'new () => A'.
+  Property 'prop' is missing in type 'A' but required in type 'A'.
+
+
+==== tests/cases/compiler/classExpressionAssignment.ts (1 errors) ====
+    interface A {
+      prop: string;
+    }
+    
+    // This is invalid
+    const A: {new(): A} = class {}
+          ~
+!!! error TS2322: Type 'typeof A' is not assignable to type 'new () => A'.
+!!! error TS2322:   Property 'prop' is missing in type 'A' but required in type 'A'.
+!!! related TS2728 tests/cases/compiler/classExpressionAssignment.ts:2:3: 'prop' is declared here.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/classExpressionAssignment.js b/tests/baselines/reference/classExpressionAssignment.js
new file mode 100644
index 00000000000..8d924cfc44c
--- /dev/null
+++ b/tests/baselines/reference/classExpressionAssignment.js
@@ -0,0 +1,16 @@
+//// [classExpressionAssignment.ts]
+interface A {
+  prop: string;
+}
+
+// This is invalid
+const A: {new(): A} = class {}
+
+
+//// [classExpressionAssignment.js]
+// This is invalid
+var A = /** @class */ (function () {
+    function A() {
+    }
+    return A;
+}());
diff --git a/tests/baselines/reference/classExpressionAssignment.symbols b/tests/baselines/reference/classExpressionAssignment.symbols
new file mode 100644
index 00000000000..a1d8abd41cf
--- /dev/null
+++ b/tests/baselines/reference/classExpressionAssignment.symbols
@@ -0,0 +1,13 @@
+=== tests/cases/compiler/classExpressionAssignment.ts ===
+interface A {
+>A : Symbol(A, Decl(classExpressionAssignment.ts, 0, 0), Decl(classExpressionAssignment.ts, 5, 5))
+
+  prop: string;
+>prop : Symbol(A.prop, Decl(classExpressionAssignment.ts, 0, 13))
+}
+
+// This is invalid
+const A: {new(): A} = class {}
+>A : Symbol(A, Decl(classExpressionAssignment.ts, 0, 0), Decl(classExpressionAssignment.ts, 5, 5))
+>A : Symbol(A, Decl(classExpressionAssignment.ts, 0, 0), Decl(classExpressionAssignment.ts, 5, 5))
+
diff --git a/tests/baselines/reference/classExpressionAssignment.types b/tests/baselines/reference/classExpressionAssignment.types
new file mode 100644
index 00000000000..cfbf796d76d
--- /dev/null
+++ b/tests/baselines/reference/classExpressionAssignment.types
@@ -0,0 +1,11 @@
+=== tests/cases/compiler/classExpressionAssignment.ts ===
+interface A {
+  prop: string;
+>prop : string
+}
+
+// This is invalid
+const A: {new(): A} = class {}
+>A : new () => A
+>class {} : typeof A
+
diff --git a/tests/cases/compiler/classExpressionAssignment.ts b/tests/cases/compiler/classExpressionAssignment.ts
new file mode 100644
index 00000000000..4ad56188a76
--- /dev/null
+++ b/tests/cases/compiler/classExpressionAssignment.ts
@@ -0,0 +1,6 @@
+interface A {
+  prop: string;
+}
+
+// This is invalid
+const A: {new(): A} = class {}