Fix issue requiring prefix on a generic interface declaration.

releasenotes.md

@@ -6,7 +6,7 @@
 - None yet.
 
 ### Fixes
-- None yet.
+- Fix issue requiring prefix on a generic interface declaration.
 
 ### Stdlib changes
 - Added '%h' and '%H' for printing out binary data in hexadecimal using the formatter.

src/compiler/compiler_internal.h

@@ -3214,7 +3214,9 @@ INLINE bool decl_is_user_defined_type(Decl *decl)
 {
 	DeclKind kind = decl->decl_kind;
 	return (kind == DECL_UNION) | (kind == DECL_STRUCT) | (kind == DECL_BITSTRUCT)
-			| (kind == DECL_ENUM) | (kind == DECL_TYPEDEF) || (kind == DECL_DISTINCT);
+			| (kind == DECL_ENUM) | (kind == DECL_TYPEDEF) | (kind == DECL_DISTINCT)
+			| (kind == DECL_INTERFACE)
+			;
 }
 
 INLINE Decl *decl_flatten(Decl *decl)

test/test_suite/any/generic_interface.c3

@@ -0,0 +1,12 @@
+module foo(<Type>);
+
+interface Baz
+{}
+
+module test;
+import foo;
+
+fn void main()
+{
+	Baz(<int>) x;
+}