Fix panic in instantiateAliasOrInterfaceWithDefaults for non-interface types

Add nil check for AsInterfaceType() to prevent SIGSEGV when
JSX.LibraryManagedAttributes has an unexpected type like an enum.
Add test case to reproduce the issue.

Agent-Logs-Url: https://github.com/microsoft/typescript-go/sessions/b1693337-08f1-4c05-b861-3cf0317ca5d2

Co-authored-by: jakebailey <5341706+jakebailey@users.noreply.github.com>

Author: Copilot

internal/checker/jsx.go

@@ -1041,7 +1041,7 @@ func (c *Checker) instantiateAliasOrInterfaceWithDefaults(managedSym *ast.Symbol
 			return c.getTypeAliasInstantiation(managedSym, args, nil)
 		}
 	}
-	if len(declaredManagedType.AsInterfaceType().TypeParameters()) >= len(typeArguments) {
+	if declaredManagedType.AsInterfaceType() != nil && len(declaredManagedType.AsInterfaceType().TypeParameters()) >= len(typeArguments) {
 		args := c.fillMissingTypeArguments(typeArguments, declaredManagedType.AsInterfaceType().TypeParameters(), len(typeArguments), inJavaScript)
 		return c.createTypeReference(declaredManagedType, args)
 	}

testdata/baselines/reference/compiler/jsxLibraryManagedAttributesUnexpectedType.errors.txt

@@ -0,0 +1,14 @@
+jsxLibraryManagedAttributesUnexpectedType.tsx(7,12): error TS2874: This JSX tag requires 'React' to be in scope, but it could not be found.
+
+
+==== jsxLibraryManagedAttributesUnexpectedType.tsx (1 errors) ====
+    declare namespace JSX {
+      enum LibraryManagedAttributes {}
+    }
+    
+    declare const C: () => any;
+    
+    const x = <C />;
+               ~
+!!! error TS2874: This JSX tag requires 'React' to be in scope, but it could not be found.
+    

testdata/baselines/reference/compiler/jsxLibraryManagedAttributesUnexpectedType.js

@@ -0,0 +1,15 @@
+//// [tests/cases/compiler/jsxLibraryManagedAttributesUnexpectedType.tsx] ////
+
+//// [jsxLibraryManagedAttributesUnexpectedType.tsx]
+declare namespace JSX {
+  enum LibraryManagedAttributes {}
+}
+
+declare const C: () => any;
+
+const x = <C />;
+
+
+//// [jsxLibraryManagedAttributesUnexpectedType.js]
+"use strict";
+const x = React.createElement(C, null);

testdata/baselines/reference/compiler/jsxLibraryManagedAttributesUnexpectedType.symbols

@@ -0,0 +1,17 @@
+//// [tests/cases/compiler/jsxLibraryManagedAttributesUnexpectedType.tsx] ////
+
+=== jsxLibraryManagedAttributesUnexpectedType.tsx ===
+declare namespace JSX {
+>JSX : Symbol(JSX, Decl(jsxLibraryManagedAttributesUnexpectedType.tsx, 0, 0))
+
+  enum LibraryManagedAttributes {}
+>LibraryManagedAttributes : Symbol(LibraryManagedAttributes, Decl(jsxLibraryManagedAttributesUnexpectedType.tsx, 0, 23))
+}
+
+declare const C: () => any;
+>C : Symbol(C, Decl(jsxLibraryManagedAttributesUnexpectedType.tsx, 4, 13))
+
+const x = <C />;
+>x : Symbol(x, Decl(jsxLibraryManagedAttributesUnexpectedType.tsx, 6, 5))
+>C : Symbol(C, Decl(jsxLibraryManagedAttributesUnexpectedType.tsx, 4, 13))
+

testdata/baselines/reference/compiler/jsxLibraryManagedAttributesUnexpectedType.types

@@ -0,0 +1,18 @@
+//// [tests/cases/compiler/jsxLibraryManagedAttributesUnexpectedType.tsx] ////
+
+=== jsxLibraryManagedAttributesUnexpectedType.tsx ===
+declare namespace JSX {
+>JSX : typeof JSX
+
+  enum LibraryManagedAttributes {}
+>LibraryManagedAttributes : LibraryManagedAttributes
+}
+
+declare const C: () => any;
+>C : () => any
+
+const x = <C />;
+>x : any
+><C /> : any
+>C : () => any
+

testdata/tests/cases/compiler/jsxLibraryManagedAttributesUnexpectedType.tsx

@@ -0,0 +1,9 @@
+// @jsx: react
+
+declare namespace JSX {
+  enum LibraryManagedAttributes {}
+}
+
+declare const C: () => any;
+
+const x = <C />;