Add array to void* implicit cast (#541)

self_hosted/typecheck.jou

@@ -31,6 +31,7 @@ def can_cast_implicitly(from: Type*, to: Type*) -> bool:
     return (
         from == to
         or (from->kind == TypeKind::Array and to->kind == TypeKind::Pointer and from->array.item_type == to->value_type)
+        or (from->kind == TypeKind::Array and to->kind == TypeKind::VoidPointer)
         or (
             from->is_integer_type()
             and to->is_integer_type()
@@ -46,6 +47,7 @@ def can_cast_explicitly(from: Type*, to: Type*) -> bool:
     return (
         from == to
         or (from->kind == TypeKind::Array and to->kind == TypeKind::Pointer and from->array.item_type == to->value_type)
+        or (from->kind == TypeKind::Array and to->kind == TypeKind::VoidPointer)
         or (from->is_pointer_type() and to->is_pointer_type())
         or (from->is_number_type() and to->is_number_type())
         or (from->is_integer_type() and to->kind == TypeKind::Enum)
@@ -165,7 +167,7 @@ class ExpressionTypes:
             fail_with_implicit_cast_error(error_location, error_template, from, to)
 
         self->implicit_cast_type = to
-        if from->kind == TypeKind::Array and to->kind == TypeKind::Pointer:
+        if from->kind == TypeKind::Array and to->is_pointer_type():
             self->implicit_array_to_pointer_cast = True
             ensure_can_take_address(
                 self->expression,

src/typecheck.c

@@ -541,8 +541,11 @@ static bool can_cast_implicitly(const Type *from, const Type *to)
     return
         from == to
         || (
-            // array to pointer implicitly
+            // array to pointer with same item type
             from->kind == TYPE_ARRAY && to->kind == TYPE_POINTER && from->data.array.membertype == to->data.valuetype
+        ) || (
+            // array to void*
+            from->kind == TYPE_ARRAY && to->kind == TYPE_VOID_POINTER
         ) || (
             // Cast to bigger integer types implicitly, unless it is signed-->unsigned.
             is_integer_type(from)
@@ -594,7 +597,7 @@ static void do_implicit_cast(
         fail_with_implicit_cast_error(location, errormsg_template, from, to);
 
     types->implicit_cast_type = to;
-    types->implicit_array_to_pointer_cast = (from->kind == TYPE_ARRAY && to->kind == TYPE_POINTER);
+    types->implicit_array_to_pointer_cast = (from->kind == TYPE_ARRAY && is_pointer_type(to));
     if (types->implicit_array_to_pointer_cast)
         ensure_can_take_address(
             fom,
@@ -620,6 +623,7 @@ static void do_explicit_cast(const FunctionOrMethodTypes *fom, ExpressionTypes *
     if (
         from != to
         && !(from->kind == TYPE_ARRAY && to->kind == TYPE_POINTER && from->data.array.membertype == to->data.valuetype)
+        && !(from->kind == TYPE_ARRAY && to->kind == TYPE_VOID_POINTER)
         && !(is_pointer_type(from) && is_pointer_type(to))
         && !(is_number_type(from) && is_number_type(to))
         && !(is_integer_type(from) && to->kind == TYPE_ENUM)

tests/should_succeed/array_to_voidptr.jou

@@ -0,0 +1,17 @@
+import "stdlib/io.jou"
+import "stdlib/mem.jou"
+
+
+def main() -> int:
+    # Implicit cast
+    array = [1, 2, 3, 4]
+    p: void* = array
+    memset(p, 0, 4)
+    printf("[%d, %d, %d]\n", array[0], array[1], array[2])  # Output: [0, 2, 3]
+
+    # Explicit cast
+    array = [1, 2, 3, 4]
+    memset(array as void*, 0, 4)
+    printf("[%d, %d, %d]\n", array[0], array[1], array[2])  # Output: [0, 2, 3]
+
+    return 0