Fix crash in expando assignment to alias

src/compiler/binder.ts

@@ -2870,7 +2870,7 @@ namespace ts {
                     }
                 });
             }
-            if (containerIsClass && namespaceSymbol) {
+            if (containerIsClass && namespaceSymbol && namespaceSymbol.valueDeclaration) {
                 addDeclarationToSymbol(namespaceSymbol, namespaceSymbol.valueDeclaration, SymbolFlags.Class);
             }
             return namespaceSymbol;

tests/baselines/reference/importAliasModuleExports.errors.txt

@@ -0,0 +1,20 @@
+tests/cases/conformance/salsa/main.js(2,13): error TS2339: Property 'foo' does not exist on type 'Alias'.
+tests/cases/conformance/salsa/main.js(4,9): error TS2339: Property 'foo' does not exist on type 'Alias'.
+
+
+==== tests/cases/conformance/salsa/mod1.js (0 errors) ====
+    class Alias {
+        bar() { return 1 }
+    }
+    module.exports = Alias;
+
+==== tests/cases/conformance/salsa/main.js (2 errors) ====
+    import A from './mod1'
+    A.prototype.foo = 0
+                ~~~
+!!! error TS2339: Property 'foo' does not exist on type 'Alias'.
+    new A().bar
+    new A().foo
+            ~~~
+!!! error TS2339: Property 'foo' does not exist on type 'Alias'.
+

tests/baselines/reference/importAliasModuleExports.symbols

@@ -0,0 +1,30 @@
+=== tests/cases/conformance/salsa/mod1.js ===
+class Alias {
+>Alias : Symbol(Alias, Decl(mod1.js, 0, 0))
+
+    bar() { return 1 }
+>bar : Symbol(Alias.bar, Decl(mod1.js, 0, 13))
+}
+module.exports = Alias;
+>module.exports : Symbol("tests/cases/conformance/salsa/mod1", Decl(mod1.js, 0, 0))
+>module : Symbol(export=, Decl(mod1.js, 2, 1))
+>exports : Symbol(export=, Decl(mod1.js, 2, 1))
+>Alias : Symbol(Alias, Decl(mod1.js, 0, 0))
+
+=== tests/cases/conformance/salsa/main.js ===
+import A from './mod1'
+>A : Symbol(A, Decl(main.js, 0, 6))
+
+A.prototype.foo = 0
+>A.prototype : Symbol(A.prototype)
+>A : Symbol(A, Decl(main.js, 0, 6))
+>prototype : Symbol(A.prototype)
+
+new A().bar
+>new A().bar : Symbol(A.bar, Decl(mod1.js, 0, 13))
+>A : Symbol(A, Decl(main.js, 0, 6))
+>bar : Symbol(A.bar, Decl(mod1.js, 0, 13))
+
+new A().foo
+>A : Symbol(A, Decl(main.js, 0, 6))
+

tests/baselines/reference/importAliasModuleExports.types

@@ -0,0 +1,40 @@
+=== tests/cases/conformance/salsa/mod1.js ===
+class Alias {
+>Alias : Alias
+
+    bar() { return 1 }
+>bar : () => number
+>1 : 1
+}
+module.exports = Alias;
+>module.exports = Alias : typeof Alias
+>module.exports : typeof Alias
+>module : { "tests/cases/conformance/salsa/mod1": typeof Alias; }
+>exports : typeof Alias
+>Alias : typeof Alias
+
+=== tests/cases/conformance/salsa/main.js ===
+import A from './mod1'
+>A : typeof A
+
+A.prototype.foo = 0
+>A.prototype.foo = 0 : 0
+>A.prototype.foo : any
+>A.prototype : A
+>A : typeof A
+>prototype : A
+>foo : any
+>0 : 0
+
+new A().bar
+>new A().bar : () => number
+>new A() : A
+>A : typeof A
+>bar : () => number
+
+new A().foo
+>new A().foo : any
+>new A() : A
+>A : typeof A
+>foo : any
+

tests/cases/conformance/salsa/importAliasModuleExports.ts

@@ -0,0 +1,15 @@
+// @allowJs: true
+// @checkJs: true
+// @noEmit: true
+// @esModuleInterop: true
+// @filename: mod1.js
+class Alias {
+    bar() { return 1 }
+}
+module.exports = Alias;
+
+// @filename: main.js
+import A from './mod1'
+A.prototype.foo = 0
+new A().bar
+new A().foo