Support bool and char literals as arguments to const generics.

tests/rust/const_generics_bool.rs

@@ -0,0 +1,57 @@
+use std::mem::MaybeUninit;
+
+use libc::c_char;
+
+#[repr(C)]
+pub struct HashTable<K, V, const IS_MAP: bool> {
+    num_buckets: usize,
+    capacity: usize,
+    occupied: *mut u8,
+    keys: *mut MaybeUninit<K>,
+    vals: *mut MaybeUninit<V>,
+}
+
+type Str = *const c_char;
+pub type HashMap<K, V> = HashTable<K, V, true>;
+pub type HashSet<K> = HashTable<K, u8, false>;
+
+impl<K, V, const IS_MAP: bool> HashTable<K, V, IS_MAP>
+{
+    pub fn new() -> Self {
+        HashTable {
+            num_buckets: 0,
+            capacity: 0,
+            occupied: std::ptr::null_mut(),
+            keys: std::ptr::null_mut(),
+            vals: std::ptr::null_mut(),
+        }
+    }
+}
+
+// with alias
+type MySet = HashTable<Str, c_char, false>;
+
+#[no_mangle]
+pub extern "C" fn new_set() -> *mut MySet {
+    Box::into_raw(Box::new(HashSet::new()))
+}
+
+type SetCallback = unsafe extern "C" fn(key: Str);
+
+#[no_mangle]
+pub unsafe extern "C" fn set_for_each(set: *const MySet, callback: SetCallback) {
+    todo!();
+}
+
+// without alias
+#[no_mangle]
+pub extern "C" fn new_map() -> *mut HashTable<Str, u64, true> {
+    Box::into_raw(Box::new(HashMap::new()))
+}
+
+type MapCallback = unsafe extern "C" fn(key: Str, val: u64);
+
+#[no_mangle]
+pub unsafe extern "C" fn map_for_each(map: *const HashTable<Str, u64, true>, callback: MapCallback) {
+    todo!();
+}

tests/rust/const_generics_char.rs

@@ -0,0 +1,20 @@
+use std::marker::PhantomData;
+
+#[repr(C)]
+struct TakeUntil<'a, const V: char>
+{
+    marker: PhantomData<&'a str>,
+    start: *const u8,
+    len: usize,
+    point: usize,
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn until_nul(start: *const u8, len: usize) -> TakeUntil<'a, '\0'> {
+    TakeUntil {
+        marker: PhantomData,
+        start,
+        len,
+        point: 0,
+    }
+}