diff --git a/packages/fcl-passrc/src/pasresolver.pp b/packages/fcl-passrc/src/pasresolver.pp
index a869b634d5..dac722710a 100644
--- a/packages/fcl-passrc/src/pasresolver.pp
+++ b/packages/fcl-passrc/src/pasresolver.pp
@@ -1492,6 +1492,7 @@ type
 function GetObjName(o: TObject): string;
 function GetTreeDbg(El: TPasElement; Indent: integer = 0): string;
 function GetResolverResultDbg(const T: TPasResolverResult): string;
+function GetClassAncestorsDbg(El: TPasClassType): string;
 function ResolverResultFlagsToStr(const Flags: TPasResolverResultFlags): string;
 
 procedure SetResolverIdentifier(out ResolvedType: TPasResolverResult;
@@ -1676,6 +1677,42 @@ begin
          +']';
 end;
 
+function GetClassAncestorsDbg(El: TPasClassType): string;
+
+  function GetClassDesc(C: TPasClassType): string;
+  var
+    Module: TPasModule;
+  begin
+    if C.IsExternal then
+      Result:='class external '
+    else
+      Result:='class ';
+    Module:=C.GetModule;
+    if Module<>nil then
+      Result:=Result+Module.Name+'.';
+    Result:=Result+C.FullName;
+  end;
+
+var
+  Scope, AncestorScope: TPasClassScope;
+  AncestorEl: TPasClassType;
+begin
+  if El=nil then exit('nil');
+  Result:=GetClassDesc(El);
+  if El.CustomData is TPasClassScope then
+    begin
+    Scope:=TPasClassScope(El.CustomData);
+    AncestorScope:=Scope.AncestorScope;
+    while AncestorScope<>nil do
+      begin
+      Result:=Result+LineEnding+'  ';
+      AncestorEl:=AncestorScope.Element as TPasClassType;
+      Result:=Result+GetClassDesc(AncestorEl);
+      AncestorScope:=AncestorScope.AncestorScope;
+      end;
+    end;
+end;
+
 function ResolverResultFlagsToStr(const Flags: TPasResolverResultFlags): string;
 var
   f: TPasResolverResultFlag;
@@ -6248,6 +6285,17 @@ begin
             SetBaseType(btBoolean);
             exit;
             end
+          else if CheckSrcIsADstType(LeftResolved,RightResolved,Bin)<>cIncompatible then
+            begin
+            // e.g. if Image is TObject then ;
+            // This is useful after some unchecked typecast -> allow
+            SetBaseType(btBoolean);
+            exit;
+            end;
+          {$IFDEF VerbosePasResolver}
+          writeln('TPasResolver.ComputeBinaryExpr LeftClass=',GetClassAncestorsDbg(TPasClassType(LeftResolved.TypeEl)));
+          writeln('TPasResolver.ComputeBinaryExpr RightClass=',GetClassAncestorsDbg(TPasClassType(RightResolved.IdentEl)));
+          {$ENDIF}
           end
         else if (RightResolved.TypeEl is TPasClassOfType)
             and (rrfReadable in RightResolved.Flags) then
@@ -6258,7 +6306,7 @@ begin
             begin
             SetBaseType(btBoolean);
             exit;
-            end
+            end;
           end
         else
           RaiseXExpectedButYFound(20170216152625,'class type',RightResolved.TypeEl.ElementTypeName,Bin.right);
diff --git a/packages/fcl-passrc/tests/tcresolver.pas b/packages/fcl-passrc/tests/tcresolver.pas
index 5bce3fe52d..23ae9d7f11 100644
--- a/packages/fcl-passrc/tests/tcresolver.pas
+++ b/packages/fcl-passrc/tests/tcresolver.pas
@@ -5378,6 +5378,7 @@ begin
   Add('begin');
   Add('  if {@o}o is {@A}TClassA then;');
   Add('  if {@v}v is {@A}TClassA then;');
+  Add('  if {@v}v is {@TOBJ}TObject then;');
   Add('  if {@v}v.{@Sub}Sub is {@A}TClassA then;');
   Add('  {@v}v:={@o}o as {@A}TClassA;');
   ParseProgram;