diff --git a/compiler/nset.pas b/compiler/nset.pas
index fa321aa9ed..3d4ae61bde 100644
--- a/compiler/nset.pas
+++ b/compiler/nset.pas
@@ -1305,7 +1305,11 @@ implementation
       begin
         { Check label type coverage for enumerations and small types }
         getrange(left.resultdef,lv,hv);
-        typcount:=hv-lv;
+        { low/high value of c-style booleans are not suitable for calculating their "type count" }
+        if is_cbool(left.resultdef) then
+          typcount:=1
+        else
+          typcount:=hv-lv;
         if not assigned(elseblock) then
           begin
             { unless cs_check_all_case_coverage is set, only check for enums, booleans and
diff --git a/tests/webtbs/tw41025.pp b/tests/webtbs/tw41025.pp
new file mode 100644
index 0000000000..5e10c01874
--- /dev/null
+++ b/tests/webtbs/tw41025.pp
@@ -0,0 +1,13 @@
+{ %OPT=-Sew }
+program a;
+uses types;
+
+var b:longbool;
+
+begin
+  b:=false;
+  case b of
+  true: writeln('True');
+  false: writeln('False');
+  end;
+end.