diff --git a/.gitattributes b/.gitattributes
index 88f2c0ee3d..9b2f4398cc 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -10111,6 +10111,7 @@ tests/webtbs/tw15088.pp svneol=native#text/plain
 tests/webtbs/tw15169.pp svneol=native#text/plain
 tests/webtbs/tw15207.pp svneol=native#text/plain
 tests/webtbs/tw15274.pp svneol=native#text/plain
+tests/webtbs/tw15304.pp svneol=native#text/plain
 tests/webtbs/tw1532.pp svneol=native#text/plain
 tests/webtbs/tw1539.pp svneol=native#text/plain
 tests/webtbs/tw1567.pp svneol=native#text/plain
diff --git a/compiler/ninl.pas b/compiler/ninl.pas
index c376d36e54..67858d0184 100644
--- a/compiler/ninl.pas
+++ b/compiler/ninl.pas
@@ -2621,9 +2621,9 @@ implementation
 
                    if not((hpp.resultdef.typ=orddef) and
 {$ifndef cpu64bitaddr}
-                          (torddef(hpp.resultdef).ordtype<>u32bit)) then
+                          (torddef(hpp.resultdef).ordtype=u32bit)) then
 {$else not cpu64bitaddr}
-                          (torddef(hpp.resultdef).ordtype<>u64bit)) then
+                          (torddef(hpp.resultdef).ordtype=u64bit)) then
 {$endif not cpu64bitaddr}
                      inserttypeconv_internal(hpp,sinttype);
                    { make sure we don't call functions part of the left node twice (and generally }
diff --git a/tests/webtbs/tw15304.pp b/tests/webtbs/tw15304.pp
new file mode 100644
index 0000000000..0dfab16814
--- /dev/null
+++ b/tests/webtbs/tw15304.pp
@@ -0,0 +1,10 @@
+{$r+,q+}
+
+var A : LongWord;
+
+begin
+  A := $0FFFFFFF;
+  Inc(A, LongWord($F0000000));
+  // no runtime error if the above line is changed to:
+  // A := A + LongWord($F0000000);
+end.