From 0774bb81ceb1e47a85338d94a9ea01879e476d34 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <293473+sandersn@users.noreply.github.com>
Date: Mon, 19 Nov 2018 13:29:46 -0800
Subject: [PATCH] Fix crash on property assignment of unresolved module
 (#28606)

Previously, the compiler would crash when binding a non-top-level
property assignment on the symbol of an unresolved module:

```js
import x from 'arglebaz'
{
    x.bar = 1
}
```

That's because `x` looks like an alias but doesn't have a
valueDeclaration (since there is no file named 'arglebaz'), and the new
code for binding Object.defineProperty calls forgot to check for an
undefined valueDeclaration.

This change adds the checks for an undefined valueDeclaration.
---
 src/compiler/binder.ts                               |  2 +-
 ...tyAssignmentOnUnresolvedImportedSymbol.errors.txt | 11 +++++++++++
 ...pertyAssignmentOnUnresolvedImportedSymbol.symbols |  8 ++++++++
 ...ropertyAssignmentOnUnresolvedImportedSymbol.types | 12 ++++++++++++
 .../propertyAssignmentOnUnresolvedImportedSymbol.ts  |  8 ++++++++
 5 files changed, 40 insertions(+), 1 deletion(-)
 create mode 100644 tests/baselines/reference/propertyAssignmentOnUnresolvedImportedSymbol.errors.txt
 create mode 100644 tests/baselines/reference/propertyAssignmentOnUnresolvedImportedSymbol.symbols
 create mode 100644 tests/baselines/reference/propertyAssignmentOnUnresolvedImportedSymbol.types
 create mode 100644 tests/cases/conformance/salsa/propertyAssignmentOnUnresolvedImportedSymbol.ts

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index fcd9b854c49..7cb321a95fa 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -2608,7 +2608,7 @@ namespace ts {
                 return true;
             }
             const node = symbol.valueDeclaration;
-            if (isCallExpression(node)) {
+            if (node && isCallExpression(node)) {
                 return !!getAssignedExpandoInitializer(node);
             }
             let init = !node ? undefined :
diff --git a/tests/baselines/reference/propertyAssignmentOnUnresolvedImportedSymbol.errors.txt b/tests/baselines/reference/propertyAssignmentOnUnresolvedImportedSymbol.errors.txt
new file mode 100644
index 00000000000..447285b8328
--- /dev/null
+++ b/tests/baselines/reference/propertyAssignmentOnUnresolvedImportedSymbol.errors.txt
@@ -0,0 +1,11 @@
+tests/cases/conformance/salsa/bug28576.js(1,15): error TS2307: Cannot find module 'arglebaz'.
+
+
+==== tests/cases/conformance/salsa/bug28576.js (1 errors) ====
+    import x from 'arglebaz'
+                  ~~~~~~~~~~
+!!! error TS2307: Cannot find module 'arglebaz'.
+    {
+        x.bar = 1
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/propertyAssignmentOnUnresolvedImportedSymbol.symbols b/tests/baselines/reference/propertyAssignmentOnUnresolvedImportedSymbol.symbols
new file mode 100644
index 00000000000..3a190cbaa86
--- /dev/null
+++ b/tests/baselines/reference/propertyAssignmentOnUnresolvedImportedSymbol.symbols
@@ -0,0 +1,8 @@
+=== tests/cases/conformance/salsa/bug28576.js ===
+import x from 'arglebaz'
+>x : Symbol(x, Decl(bug28576.js, 0, 6))
+{
+    x.bar = 1
+>x : Symbol(x, Decl(bug28576.js, 0, 6))
+}
+
diff --git a/tests/baselines/reference/propertyAssignmentOnUnresolvedImportedSymbol.types b/tests/baselines/reference/propertyAssignmentOnUnresolvedImportedSymbol.types
new file mode 100644
index 00000000000..5ff245f8475
--- /dev/null
+++ b/tests/baselines/reference/propertyAssignmentOnUnresolvedImportedSymbol.types
@@ -0,0 +1,12 @@
+=== tests/cases/conformance/salsa/bug28576.js ===
+import x from 'arglebaz'
+>x : any
+{
+    x.bar = 1
+>x.bar = 1 : 1
+>x.bar : any
+>x : any
+>bar : any
+>1 : 1
+}
+
diff --git a/tests/cases/conformance/salsa/propertyAssignmentOnUnresolvedImportedSymbol.ts b/tests/cases/conformance/salsa/propertyAssignmentOnUnresolvedImportedSymbol.ts
new file mode 100644
index 00000000000..a879367e06f
--- /dev/null
+++ b/tests/cases/conformance/salsa/propertyAssignmentOnUnresolvedImportedSymbol.ts
@@ -0,0 +1,8 @@
+// @allowJs: true
+// @checkJs: true
+// @noEmit: true
+// @Filename: bug28576.js
+import x from 'arglebaz'
+{
+    x.bar = 1
+}