diff --git a/.gitattributes b/.gitattributes
index 00bd21ac86..22002fc8fc 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -15223,6 +15223,7 @@ tests/webtbs/tw30443.pp svneol=native#text/plain
 tests/webtbs/tw3045.pp svneol=native#text/plain
 tests/webtbs/tw3048.pp svneol=native#text/plain
 tests/webtbs/tw30522.pp svneol=native#text/plain
+tests/webtbs/tw30534.pp svneol=native#text/pascal
 tests/webtbs/tw30570.pp svneol=native#text/plain
 tests/webtbs/tw30572.pp svneol=native#text/plain
 tests/webtbs/tw3063.pp svneol=native#text/plain
diff --git a/compiler/defcmp.pas b/compiler/defcmp.pas
index 310f8fa519..a9018b5a4f 100644
--- a/compiler/defcmp.pas
+++ b/compiler/defcmp.pas
@@ -275,20 +275,33 @@ implementation
            end
          else
            begin
-             { undefined defs or defs with generic constraints are
-               considered equal to everything }
-             if (
-                   (def_from.typ=undefineddef) or
-                   assigned(tstoreddef(def_from).genconstraintdata)
-                 ) or (
-                   (def_to.typ=undefineddef) or
-                   assigned(tstoreddef(def_to).genconstraintdata)
-                 ) then
-              begin
-                doconv:=tc_equal;
-                compare_defs_ext:=te_exact;
-                exit;
-              end;
+             { undefined defs are considered equal to everything }
+             if (def_from.typ=undefineddef) or
+                 (def_to.typ=undefineddef) then
+               begin
+                 doconv:=tc_equal;
+                 compare_defs_ext:=te_exact;
+                 exit;
+               end;
+
+             { either type has constraints }
+             if assigned(tstoreddef(def_from).genconstraintdata) or
+                 assigned(tstoreddef(def_to).genconstraintdata) then
+               begin
+                 if def_from.typ<>def_to.typ then
+                   begin
+                     { not compatible anyway }
+                     doconv:=tc_not_possible;
+                     compare_defs_ext:=te_incompatible;
+                     exit;
+                   end;
+
+                 { one is definitely a constraint, for the other we don't
+                   care right now }
+                 doconv:=tc_equal;
+                 compare_defs_ext:=te_exact;
+                 exit;
+               end;
            end;
 
          { two specializations are considered equal if they specialize the same
diff --git a/tests/webtbs/tw30534.pp b/tests/webtbs/tw30534.pp
new file mode 100644
index 0000000000..609b37e632
--- /dev/null
+++ b/tests/webtbs/tw30534.pp
@@ -0,0 +1,18 @@
+{ %NORUN }
+
+{$MODE DELPHI}
+
+type
+  TSmartPtr<T: class> = record
+    class operator Implicit(aValue: T): TSmartPtr<T>;
+  end;
+
+class operator TSmartPtr<T>.Implicit(aValue: T): TSmartPtr<T>;
+begin
+end;
+
+var
+  sp: TSmartPtr<TObject>;
+begin
+  sp := nil;
+end.