From a03227d60e2da470a8a964903016e2b3d0106950 Mon Sep 17 00:00:00 2001
From: Martin Probst <martin@probst.io>
Date: Thu, 24 Oct 2019 23:04:42 +0200
Subject: [PATCH] Avoid a crash with `@typedef` in a script file. (#33847)

* Avoid a crash with `@typedef` in a script file.

Scripts (as opposed to modules) do not have a symbol object. If a script
contains a `@typdef` defined on a namespace called `exports`, TypeScript
crashes because it attempts to create an exported symbol on the
(non-existent) symbol of the SourceFile.

This change avoids the crash by explicitly checking if the source file
has a symbol object, i.e. whether it is a module.

* Add usage of exports.SomeName typedef.

* Fix bug at bind site rather than in declare func
---
 src/compiler/binder.ts                        | 11 +++++++--
 ...checkJsdocTypedefOnlySourceFile.errors.txt | 18 +++++++++++++++
 .../checkJsdocTypedefOnlySourceFile.js        | 23 +++++++++++++++++++
 .../checkJsdocTypedefOnlySourceFile.symbols   | 16 +++++++++++++
 .../checkJsdocTypedefOnlySourceFile.types     | 20 ++++++++++++++++
 .../jsdoc/checkJsdocTypedefOnlySourceFile.ts  | 15 ++++++++++++
 6 files changed, 101 insertions(+), 2 deletions(-)
 create mode 100644 tests/baselines/reference/checkJsdocTypedefOnlySourceFile.errors.txt
 create mode 100644 tests/baselines/reference/checkJsdocTypedefOnlySourceFile.js
 create mode 100644 tests/baselines/reference/checkJsdocTypedefOnlySourceFile.symbols
 create mode 100644 tests/baselines/reference/checkJsdocTypedefOnlySourceFile.types
 create mode 100644 tests/cases/conformance/jsdoc/checkJsdocTypedefOnlySourceFile.ts

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 10700204010..5f36d429556 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -2003,7 +2003,12 @@ namespace ts {
                         switch (getAssignmentDeclarationPropertyAccessKind(declName.parent)) {
                             case AssignmentDeclarationKind.ExportsProperty:
                             case AssignmentDeclarationKind.ModuleExports:
-                                container = file;
+                                if (!isExternalOrCommonJsModule(file)) {
+                                    container = undefined!;
+                                }
+                                else {
+                                    container = file;
+                                }
                                 break;
                             case AssignmentDeclarationKind.ThisProperty:
                                 container = declName.parent.expression;
@@ -2017,7 +2022,9 @@ namespace ts {
                             case AssignmentDeclarationKind.None:
                                 return Debug.fail("Shouldn't have detected typedef or enum on non-assignment declaration");
                         }
-                        declareModuleMember(typeAlias, SymbolFlags.TypeAlias, SymbolFlags.TypeAliasExcludes);
+                        if (container) {
+                            declareModuleMember(typeAlias, SymbolFlags.TypeAlias, SymbolFlags.TypeAliasExcludes);
+                        }
                         container = oldContainer;
                     }
                 }
diff --git a/tests/baselines/reference/checkJsdocTypedefOnlySourceFile.errors.txt b/tests/baselines/reference/checkJsdocTypedefOnlySourceFile.errors.txt
new file mode 100644
index 00000000000..52b43068c04
--- /dev/null
+++ b/tests/baselines/reference/checkJsdocTypedefOnlySourceFile.errors.txt
@@ -0,0 +1,18 @@
+tests/cases/conformance/jsdoc/0.js(10,20): error TS2694: Namespace 'exports' has no exported member 'SomeName'.
+
+
+==== tests/cases/conformance/jsdoc/0.js (1 errors) ====
+    // @ts-check
+    
+    var exports = {};
+    
+    /**
+     * @typedef {string}
+     */
+    exports.SomeName;
+    
+    /** @type {exports.SomeName} */
+                       ~~~~~~~~
+!!! error TS2694: Namespace 'exports' has no exported member 'SomeName'.
+    const myString = 'str';
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/checkJsdocTypedefOnlySourceFile.js b/tests/baselines/reference/checkJsdocTypedefOnlySourceFile.js
new file mode 100644
index 00000000000..7f4d7f4bcfd
--- /dev/null
+++ b/tests/baselines/reference/checkJsdocTypedefOnlySourceFile.js
@@ -0,0 +1,23 @@
+//// [0.js]
+// @ts-check
+
+var exports = {};
+
+/**
+ * @typedef {string}
+ */
+exports.SomeName;
+
+/** @type {exports.SomeName} */
+const myString = 'str';
+
+
+//// [0.js]
+// @ts-check
+var exports = {};
+/**
+ * @typedef {string}
+ */
+exports.SomeName;
+/** @type {exports.SomeName} */
+var myString = 'str';
diff --git a/tests/baselines/reference/checkJsdocTypedefOnlySourceFile.symbols b/tests/baselines/reference/checkJsdocTypedefOnlySourceFile.symbols
new file mode 100644
index 00000000000..0adf9a93444
--- /dev/null
+++ b/tests/baselines/reference/checkJsdocTypedefOnlySourceFile.symbols
@@ -0,0 +1,16 @@
+=== tests/cases/conformance/jsdoc/0.js ===
+// @ts-check
+
+var exports = {};
+>exports : Symbol(exports, Decl(0.js, 2, 3))
+
+/**
+ * @typedef {string}
+ */
+exports.SomeName;
+>exports : Symbol(exports, Decl(0.js, 2, 3))
+
+/** @type {exports.SomeName} */
+const myString = 'str';
+>myString : Symbol(myString, Decl(0.js, 10, 5))
+
diff --git a/tests/baselines/reference/checkJsdocTypedefOnlySourceFile.types b/tests/baselines/reference/checkJsdocTypedefOnlySourceFile.types
new file mode 100644
index 00000000000..fbb4f3ed0ba
--- /dev/null
+++ b/tests/baselines/reference/checkJsdocTypedefOnlySourceFile.types
@@ -0,0 +1,20 @@
+=== tests/cases/conformance/jsdoc/0.js ===
+// @ts-check
+
+var exports = {};
+>exports : {}
+>{} : {}
+
+/**
+ * @typedef {string}
+ */
+exports.SomeName;
+>exports.SomeName : any
+>exports : {}
+>SomeName : any
+
+/** @type {exports.SomeName} */
+const myString = 'str';
+>myString : any
+>'str' : "str"
+
diff --git a/tests/cases/conformance/jsdoc/checkJsdocTypedefOnlySourceFile.ts b/tests/cases/conformance/jsdoc/checkJsdocTypedefOnlySourceFile.ts
new file mode 100644
index 00000000000..d991d2f6e16
--- /dev/null
+++ b/tests/cases/conformance/jsdoc/checkJsdocTypedefOnlySourceFile.ts
@@ -0,0 +1,15 @@
+// @allowJS: true
+// @suppressOutputPathCheck: true
+
+// @filename: 0.js
+// @ts-check
+
+var exports = {};
+
+/**
+ * @typedef {string}
+ */
+exports.SomeName;
+
+/** @type {exports.SomeName} */
+const myString = 'str';