Fix Int->Num promotions

builtins/integers.c

@@ -36,6 +36,14 @@ public Int_t Int$from_num(double n)
     return Int$from_mpz(result);
 }
 
+public double Int$as_num(Int_t i)
+{
+    if (__builtin_expect(i.small & 1, 1))
+        return (double)(i.small >> 2);
+
+    return mpz_get_d(*i.big);
+}
+
 public CORD Int$as_text(const Int_t *i, bool colorize, const TypeInfo *type) {
     (void)type;
     if (!i) return "Int";

builtins/integers.h

@@ -79,6 +79,7 @@ Int_t Int$abs(Int_t x);
 #define Int$as_i64(i) (((i).small & 1) ? (int64_t)((i).small >> 2) : mpz_get_si(*(i).big))
 Int_t Int$from_i64(int64_t i);
 Int_t Int$from_num(double n);
+double Int$as_num(Int_t i);
 #define I(i) ((int64_t)(i) == (int32_t)(i) ? ((Int_t){.small=((uint64_t)(i)<<2)|1}) : Int$from_i64(i))
 
 Int_t Int$plus(Int_t x, Int_t y);

compile.c

@@ -36,6 +36,11 @@ static bool promote(env_t *env, CORD *code, type_t *actual, type_t *needed)
         return true;
     }
 
+    if (actual->tag == IntType && Match(actual, IntType)->bits == 0 && needed->tag == NumType) {
+        *code = CORD_all("Int$as_num(", *code, ")");
+        return true;
+    }
+
     if (actual->tag == IntType || actual->tag == NumType)
         return true;