[ fix ] Add missing cases for BITS types in extractInt

e79e4277 ("[ fix ] Make Bits types use int switch statement in RefC")
made the RefC backend generate code calling `extractInt` with Bits
types, bit did not add the extra cases to `extractInt`. This commit adds
the missing cases.

Fixes #2452

support/refc/runtime.c

@@ -69,6 +69,14 @@ Value *tailcall_apply_closure(Value *_clos, Value *arg) {
 
 int extractInt(Value *v) {
   switch (v->header.tag) {
+  case BITS8_TAG:
+    return (int)((Value_Bits8 *)v)->ui8;
+  case BITS16_TAG:
+    return (int)((Value_Bits16 *)v)->ui16;
+  case BITS32_TAG:
+    return (int)((Value_Bits32 *)v)->ui32;
+  case BITS64_TAG:
+    return (int)((Value_Bits64 *)v)->ui64;
   case INT8_TAG:
     return (int)((Value_Int8 *)v)->i8;
   case INT16_TAG:

tests/refc/issue2452/BitsCase.idr

@@ -0,0 +1,9 @@
+x : Bits8
+x = 0
+
+main : IO ()
+main = do
+  putStrLn $
+    case x of
+      0 => "good"
+      _ => "bad"

tests/refc/issue2452/expected

@@ -0,0 +1 @@
+good

tests/refc/issue2452/run

@@ -0,0 +1,4 @@
+rm -rf build
+
+$1 --no-banner --no-color --console-width 0 --cg refc -o bits_case BitsCase.idr > /dev/null
+./build/exec/bits_case