if a location is specified by regex, then always compile an "alias",
even into one static string script: this elimates testing this
too specific case inside ngx_http_map_uri_to_path()
diff --git a/src/http/ngx_http_core_module.c b/src/http/ngx_http_core_module.c
index 6a11a87..b438907 100644
--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -3788,13 +3788,19 @@
     n = ngx_http_script_variables_count(&clcf->root);
 
     ngx_memzero(&sc, sizeof(ngx_http_script_compile_t));
+    sc.variables = n;
+
+#if (NGX_PCRE)
+    if (alias && clcf->regex) {
+        n = 1;
+    }
+#endif
 
     if (n) {
         sc.cf = cf;
         sc.source = &clcf->root;
         sc.lengths = &clcf->root_lengths;
         sc.values = &clcf->root_values;
-        sc.variables = n;
         sc.complete_lengths = 1;
         sc.complete_values = 1;