From b86dea03f2ca8ba71f46383dd5e7895fa5741143 Mon Sep 17 00:00:00 2001
From: Wesley Wigham <wwigham@gmail.com>
Date: Thu, 21 Mar 2019 18:27:14 -0700
Subject: [PATCH] Fix crash caused by cyclic defaults (#30532)

---
 src/compiler/checker.ts                         |  8 ++++----
 ...ReferentialDefaultNoStackOverflow.errors.txt | 16 ++++++++++++++++
 .../selfReferentialDefaultNoStackOverflow.js    | 17 +++++++++++++++++
 ...elfReferentialDefaultNoStackOverflow.symbols | 13 +++++++++++++
 .../selfReferentialDefaultNoStackOverflow.types | 17 +++++++++++++++++
 .../selfReferentialDefaultNoStackOverflow.ts    | 11 +++++++++++
 6 files changed, 78 insertions(+), 4 deletions(-)
 create mode 100644 tests/baselines/reference/selfReferentialDefaultNoStackOverflow.errors.txt
 create mode 100644 tests/baselines/reference/selfReferentialDefaultNoStackOverflow.js
 create mode 100644 tests/baselines/reference/selfReferentialDefaultNoStackOverflow.symbols
 create mode 100644 tests/baselines/reference/selfReferentialDefaultNoStackOverflow.types
 create mode 100644 tests/cases/compiler/selfReferentialDefaultNoStackOverflow.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 22333f4ec02..a261a6c38d7 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5474,9 +5474,6 @@ namespace ts {
                 }
                 return type;
             }
-            if (declaration.kind === SyntaxKind.ExportAssignment) {
-                return widenTypeForVariableLikeDeclaration(checkExpressionCached((<ExportAssignment>declaration).expression), declaration);
-            }
 
             // Handle variable, parameter or property
             if (!pushTypeResolution(symbol, TypeSystemPropertyName.Type)) {
@@ -5487,7 +5484,10 @@ namespace ts {
                 return reportCircularityError(symbol);
             }
             let type: Type | undefined;
-            if (isInJSFile(declaration) &&
+            if (declaration.kind === SyntaxKind.ExportAssignment) {
+                type = widenTypeForVariableLikeDeclaration(checkExpressionCached((<ExportAssignment>declaration).expression), declaration);
+            }
+            else if (isInJSFile(declaration) &&
                 (isCallExpression(declaration) || isBinaryExpression(declaration) || isPropertyAccessExpression(declaration) && isBinaryExpression(declaration.parent))) {
                 type = getWidenedTypeFromAssignmentDeclaration(symbol);
             }
diff --git a/tests/baselines/reference/selfReferentialDefaultNoStackOverflow.errors.txt b/tests/baselines/reference/selfReferentialDefaultNoStackOverflow.errors.txt
new file mode 100644
index 00000000000..9cea32dfa59
--- /dev/null
+++ b/tests/baselines/reference/selfReferentialDefaultNoStackOverflow.errors.txt
@@ -0,0 +1,16 @@
+tests/cases/compiler/QSpinner.js(3,1): error TS7022: 'default' implicitly has type 'any' because it does not have a type annotation and is referenced directly or indirectly in its own initializer.
+
+
+==== tests/cases/compiler/QSpinner.js (1 errors) ====
+    import DefaultSpinner from './QSpinner'
+    
+    export default {
+    ~~~~~~~~~~~~~~~~
+      mixins: [DefaultSpinner],
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+      name: 'QSpinner'
+    ~~~~~~~~~~~~~~~~~~
+    }
+    ~
+!!! error TS7022: 'default' implicitly has type 'any' because it does not have a type annotation and is referenced directly or indirectly in its own initializer.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/selfReferentialDefaultNoStackOverflow.js b/tests/baselines/reference/selfReferentialDefaultNoStackOverflow.js
new file mode 100644
index 00000000000..ae736acdb2f
--- /dev/null
+++ b/tests/baselines/reference/selfReferentialDefaultNoStackOverflow.js
@@ -0,0 +1,17 @@
+//// [QSpinner.js]
+import DefaultSpinner from './QSpinner'
+
+export default {
+  mixins: [DefaultSpinner],
+  name: 'QSpinner'
+}
+
+
+//// [QSpinner.js]
+"use strict";
+exports.__esModule = true;
+var QSpinner_1 = require("./QSpinner");
+exports["default"] = {
+    mixins: [QSpinner_1["default"]],
+    name: 'QSpinner'
+};
diff --git a/tests/baselines/reference/selfReferentialDefaultNoStackOverflow.symbols b/tests/baselines/reference/selfReferentialDefaultNoStackOverflow.symbols
new file mode 100644
index 00000000000..b7ead9cab77
--- /dev/null
+++ b/tests/baselines/reference/selfReferentialDefaultNoStackOverflow.symbols
@@ -0,0 +1,13 @@
+=== tests/cases/compiler/QSpinner.js ===
+import DefaultSpinner from './QSpinner'
+>DefaultSpinner : Symbol(DefaultSpinner, Decl(QSpinner.js, 0, 6))
+
+export default {
+  mixins: [DefaultSpinner],
+>mixins : Symbol(mixins, Decl(QSpinner.js, 2, 16))
+>DefaultSpinner : Symbol(DefaultSpinner, Decl(QSpinner.js, 0, 6))
+
+  name: 'QSpinner'
+>name : Symbol(name, Decl(QSpinner.js, 3, 27))
+}
+
diff --git a/tests/baselines/reference/selfReferentialDefaultNoStackOverflow.types b/tests/baselines/reference/selfReferentialDefaultNoStackOverflow.types
new file mode 100644
index 00000000000..b4d1545186f
--- /dev/null
+++ b/tests/baselines/reference/selfReferentialDefaultNoStackOverflow.types
@@ -0,0 +1,17 @@
+=== tests/cases/compiler/QSpinner.js ===
+import DefaultSpinner from './QSpinner'
+>DefaultSpinner : any
+
+export default {
+>{  mixins: [DefaultSpinner],  name: 'QSpinner'} : { mixins: any[]; name: string; }
+
+  mixins: [DefaultSpinner],
+>mixins : any[]
+>[DefaultSpinner] : any[]
+>DefaultSpinner : any
+
+  name: 'QSpinner'
+>name : string
+>'QSpinner' : "QSpinner"
+}
+
diff --git a/tests/cases/compiler/selfReferentialDefaultNoStackOverflow.ts b/tests/cases/compiler/selfReferentialDefaultNoStackOverflow.ts
new file mode 100644
index 00000000000..55199e6da29
--- /dev/null
+++ b/tests/cases/compiler/selfReferentialDefaultNoStackOverflow.ts
@@ -0,0 +1,11 @@
+// @allowJs: true
+// @checkJs: true
+// @strict: true
+// @outDir: ./out
+// @filename: QSpinner.js
+import DefaultSpinner from './QSpinner'
+
+export default {
+  mixins: [DefaultSpinner],
+  name: 'QSpinner'
+}