c bool support and c-integer coercion

compiler/types/types.odin

@@ -1094,6 +1094,20 @@ can_widen :: proc(from, to: Type) -> bool {
 	       bits(from) < bits(to)
 }
 
+// can_coerce_c_integer reports whether `from` may implicitly convert to `to`
+// under C's integer conversion rules. Brolang keeps its own exact-width scalars
+// strict (`u32 -> i32` is rejected), but C interop types deliberately follow C:
+// virtually every C library relies on it — e.g. an unsigned-backed enum constant
+// (`c_uint`) passed to an `int` (`c_int`) parameter — so disallowing it would
+// make C interop cumbersome. Scope: widening (sext/zext) and same-width
+// signedness changes (no-op reinterpret); narrowing is intentionally excluded so
+// lossy conversions stay an error, matching brolang's trap-on-narrow philosophy.
+can_coerce_c_integer :: proc(from, to: Type) -> bool {
+	return from != to && is_c(from) && is_c(to) &&
+	       is_concrete_integer(from) && is_concrete_integer(to) &&
+	       bits(from) <= bits(to)
+}
+
 widest :: proc(a, b: Type) -> Type {
 	if equal(a, b) && is_concrete_scalar(a) {
 		return a