diff --git a/libs/vkd3d-shader/preproc.l b/libs/vkd3d-shader/preproc.l
index 728d6184..d360f6ca 100644
--- a/libs/vkd3d-shader/preproc.l
+++ b/libs/vkd3d-shader/preproc.l
@@ -746,6 +746,9 @@ int yylex(YYSTYPE *lval, YYLTYPE *lloc, yyscan_t scanner)
                         if (current_arg)
                             preproc_text_add(current_arg, text);
                 }
+
+                if (current_arg)
+                    preproc_text_add(current_arg, " ");
                 break;
             }
         }
diff --git a/tests/preproc-macro.shader_test b/tests/preproc-macro.shader_test
index 8f073965..96e4b865 100644
--- a/tests/preproc-macro.shader_test
+++ b/tests/preproc-macro.shader_test
@@ -311,3 +311,9 @@ apple # KEY
 #define KEY(a) KEY2(a)
 
 KEY(pa)
+
+[preproc]
+#define KEY2(x) x
+#define KEY KEY2(fa il)
+KEY
+pass