* don't evaluate sizeof(<type param>) as a constant to avoid arithmetic errors in constant folding, resolves #20192

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@19285 3ad0048d-3df7-0310-abae-a5850022a9f2

1 files changed, 47 insertions, 0 deletions

diff --git a/tests/webtbs/tw20192.pp b/tests/webtbs/tw20192.pp
new file mode 100644
index 0000000000..67c2e18b38
--- /dev/null
+++ b/tests/webtbs/tw20192.pp
@@ -0,0 +1,47 @@
+program SizeOfBug;
+{$mode objfpc}{$H+}
+
+type
+  generic TGen<_T> = class(TObject)
+    private
+      FField: _T;
+    public
+      constructor Create(Val: _T);
+
+      function Bug: Integer;
+  end;
+
+{--- TGen.Create ---}
+constructor TGen.Create(Val: _T);
+begin
+  inherited Create;
+  FField := Val;
+end;
+
+{--- TGen.Bug ---}
+function TGen.Bug : Integer;
+begin
+  Result := 100000 div SizeOf(_T);  // *** DIVISION BY ZERO ***
+
+  // THE FOLLOWING CODE IS OK !
+  //
+  // var
+  //   S: Integer;
+  // begin
+  //   S := SizeOf(_T);
+  //   Result := 100000 div S;
+end;
+
+type
+  TGenInt = specialize TGen<Integer>;
+
+var
+  V: TGenInt;
+begin
+  V := V.Create(589);
+  WriteLn('V.Bug = ', V.Bug);
+  if V.Bug<>100000 div sizeof(pointer) then
+    halt(1);
+  V.Free;
+  writeln('ok');
+end.