diff --git a/.gitattributes b/.gitattributes
index e83b5804fe..ffbac75ece 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -12603,6 +12603,9 @@ 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/tw21593a.pp svneol=native#text/pascal
+tests/webtbs/tw21593b.pp svneol=native#text/pascal
+tests/webtbs/tw21593c.pp svneol=native#text/pascal
 tests/webtbs/tw2163.pp svneol=native#text/plain
 tests/webtbs/tw21654.pp svneol=native#text/pascal
 tests/webtbs/tw21674.pp svneol=native#text/pascal
diff --git a/compiler/pdecl.pas b/compiler/pdecl.pas
index 3a2b0ade2b..8eee372a30 100644
--- a/compiler/pdecl.pas
+++ b/compiler/pdecl.pas
@@ -153,9 +153,27 @@ implementation
                else
                 Message(parser_e_illegal_expression);
              end;
+           inlinen:
+             begin
+               { this situation only happens if a intrinsic is parsed that has a
+                 generic type as its argument. As we don't know certain
+                 information about the final type yet, we need to use safe
+                 values (mostly 0) }
+               if not parse_generic then
+                 Message(parser_e_illegal_expression);
+               case tinlinenode(p).inlinenumber of
+                 in_sizeof_x,
+                 in_bitsizeof_x:
+                   begin
+                     hp:=tconstsym.create_ord(orgname,constord,0,p.resultdef);
+                   end;
+                 { add other cases here if necessary }
+                 else
+                   Message(parser_e_illegal_expression);
+               end;
+             end;
            else
-             if not(parse_generic) then
-               Message(parser_e_illegal_expression);
+             Message(parser_e_illegal_expression);
         end;
         current_tokenpos:=storetokenpos;
         p.free;
diff --git a/tests/webtbs/tw21593a.pp b/tests/webtbs/tw21593a.pp
new file mode 100644
index 0000000000..7d95a9d943
--- /dev/null
+++ b/tests/webtbs/tw21593a.pp
@@ -0,0 +1,19 @@
+program tw21593a;
+
+{$MODE DELPHI}
+
+type
+  TWrapper<T> = record
+    class procedure Test; static;
+  end;
+
+class procedure TWrapper<T>.Test;
+const
+  Size = SizeOf(T);  { Error: Illegal expression }
+begin
+  Writeln(Size);
+end;
+
+begin
+  TWrapper<Byte>.Test;
+end.
diff --git a/tests/webtbs/tw21593b.pp b/tests/webtbs/tw21593b.pp
new file mode 100644
index 0000000000..35fd7e9932
--- /dev/null
+++ b/tests/webtbs/tw21593b.pp
@@ -0,0 +1,20 @@
+program tw21593b;
+
+{$MODE DELPHI}
+
+type
+  TWrapper<T> = record
+  strict private
+    const Size = SizeOf(T);  { Error: Illegal expression }
+  public
+    class procedure Test; static;
+  end;
+
+class procedure TWrapper<T>.Test;
+begin
+  Writeln(Size);
+end;
+
+begin
+  TWrapper<Byte>.Test;
+end.
diff --git a/tests/webtbs/tw21593c.pp b/tests/webtbs/tw21593c.pp
new file mode 100644
index 0000000000..5f44f92856
--- /dev/null
+++ b/tests/webtbs/tw21593c.pp
@@ -0,0 +1,19 @@
+program tw21593c;
+
+{$MODE DELPHI}
+
+type
+  TWrapper<T> = record
+    class procedure Test; static;
+  end;
+
+class procedure TWrapper<T>.Test;
+var
+  size: SizeInt = SizeOf(T);  { Error: Illegal expression }
+begin
+  Writeln(size);
+end;
+
+begin
+  TWrapper<Byte>.Test;
+end.