diff --git a/.gitattributes b/.gitattributes
index d722475c1a..b3bc4fa43e 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -12112,6 +12112,7 @@ tests/webtbs/tw20962.pp svneol=native#text/plain
 tests/webtbs/tw20995a.pp svneol=native#text/pascal
 tests/webtbs/tw20995b.pp svneol=native#text/pascal
 tests/webtbs/tw20998.pp svneol=native#text/pascal
+tests/webtbs/tw21029.pp svneol=native#text/plain
 tests/webtbs/tw2109.pp svneol=native#text/plain
 tests/webtbs/tw2110.pp svneol=native#text/plain
 tests/webtbs/tw2128.pp svneol=native#text/plain
diff --git a/compiler/nmat.pas b/compiler/nmat.pas
index 90258ac7af..2286a12598 100644
--- a/compiler/nmat.pas
+++ b/compiler/nmat.pas
@@ -1003,10 +1003,21 @@ implementation
                else
                  CGMessage(type_e_mismatch);
              end;
-             if not forinline then
+             { not-nodes are not range checked by the code generator -> also
+               don't range check while inlining; the resultdef is a bit tricky
+               though: the node's resultdef gets changed in most cases compared
+               to left, but the not-operation itself is caried out in the code
+               generator using the size of left
+               }
+             if not(forinline) then
                t:=cordconstnode.create(v,def,false)
              else
-               t:=create_simplified_ord_const(v,resultdef,true);
+               begin
+                 { cut off the value if necessary }
+                 t:=cordconstnode.create(v,left.resultdef,false);
+                 { now convert to node's resultdef }
+                 inserttypeconv_explicit(t,def);
+               end;
              result:=t;
              exit;
           end;
diff --git a/tests/webtbs/tw21029.pp b/tests/webtbs/tw21029.pp
new file mode 100644
index 0000000000..9d10028d76
--- /dev/null
+++ b/tests/webtbs/tw21029.pp
@@ -0,0 +1,12 @@
+{$r+}
+{$inline on}
+
+function F(y : byte) : byte; inline;
+begin
+  f:=byte(not y);
+end;
+
+BEGIN
+  if F(1)<>254 then
+    halt(1);
+END.