diff --git a/.gitattributes b/.gitattributes
index e0bdb1dcbf..e83b5804fe 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -12601,6 +12601,7 @@ tests/webtbs/tw21551.pp svneol=native#text/plain
 tests/webtbs/tw2158.pp svneol=native#text/plain
 tests/webtbs/tw2159.pp svneol=native#text/plain
 tests/webtbs/tw21592.pp svneol=native#text/pascal
+tests/webtbs/tw21592b.pp svneol=native#text/pascal
 tests/webtbs/tw21593.pp svneol=native#text/pascal
 tests/webtbs/tw2163.pp svneol=native#text/plain
 tests/webtbs/tw21654.pp svneol=native#text/pascal
diff --git a/compiler/ninl.pas b/compiler/ninl.pas
index fb28463dcd..689b3e20d4 100644
--- a/compiler/ninl.pas
+++ b/compiler/ninl.pas
@@ -2474,7 +2474,8 @@ implementation
                 begin
                   { the constant evaluation of in_sizeof_x happens in pexpr where possible }
                   set_varstate(left,vs_read,[]);
-                  if paramanager.push_high_param(vs_value,left.resultdef,current_procinfo.procdef.proccalloption) then
+                  if (left.resultdef.typ<>undefineddef) and
+                      paramanager.push_high_param(vs_value,left.resultdef,current_procinfo.procdef.proccalloption) then
                    begin
                      hightree:=load_high_value_node(tparavarsym(tloadnode(left).symtableentry));
                      if assigned(hightree) then
diff --git a/tests/webtbs/tw21592b.pp b/tests/webtbs/tw21592b.pp
new file mode 100644
index 0000000000..cc98265f64
--- /dev/null
+++ b/tests/webtbs/tw21592b.pp
@@ -0,0 +1,11 @@
+unit tw21592b;
+
+{$MODE DELPHI}
+
+interface
+
+type TBytesOverlay<T> = array [0..SizeOf(T) - 1] of Byte;
+
+implementation
+
+end.