`auto_cast` prefix for procedure parameters

core/mem/alloc.odin

@@ -104,22 +104,22 @@ new_clone_with_allocator :: inline proc(a: Allocator, data: $T, loc := #caller_l
 }
 
 
-make_slice :: proc(T: type/[]$E, len: int, loc := #caller_location) -> T {
+make_slice :: proc(T: type/[]$E, auto_cast len: int, loc := #caller_location) -> T {
 	runtime.make_slice_error_loc(loc, len);
 	data := alloc(size_of(E)*len, align_of(E));
 	s := Raw_Slice{data, len};
 	return transmute(T)s;
 }
-make_dynamic_array_len :: proc(T: type/[dynamic]$E, len: int = 16, loc := #caller_location) -> T {
+make_dynamic_array_len :: proc(T: type/[dynamic]$E, auto_cast len: int = 16, loc := #caller_location) -> T {
 	return make_dynamic_array(T, len, len, loc);
 }
-make_dynamic_array :: proc(T: type/[dynamic]$E, len, cap: int, loc := #caller_location) -> T {
+make_dynamic_array :: proc(T: type/[dynamic]$E, auto_cast len: int, auto_cast cap: int, loc := #caller_location) -> T {
 	runtime.make_dynamic_array_error_loc(loc, len, cap);
 	data := alloc(size_of(E)*cap, align_of(E));
 	s := Raw_Dynamic_Array{data, len, cap, context.allocator};
 	return transmute(T)s;
 }
-make_map :: proc(T: type/map[$K]$E, cap: int = 16, loc := #caller_location) -> T {
+make_map :: proc(T: type/map[$K]$E, auto_cast cap: int = 16, loc := #caller_location) -> T {
 	runtime.make_map_expr_error_loc(loc, cap);
 	m: T;
 	reserve_map(&m, cap);

src/check_expr.cpp

@@ -3879,10 +3879,18 @@ CALL_ARGUMENT_CHECKER(check_call_arguments_internal) {
 
 				i64 s = 0;
 				if (!check_is_assignable_to_with_score(c, &o, t, &s)) {
-					if (show_error) {
-						check_assignment(c, &o, t, str_lit("argument"));
+					bool ok = false;
+					if (e->flags & EntityFlag_AutoCast) {
+						ok = check_is_castable_to(c, &o, t);
+					}
+					if (ok) {
+						s = assign_score_function(10);
+					} else {
+						if (show_error) {
+							check_assignment(c, &o, t, str_lit("argument"));
+						}
+						err = CallArgumentError_WrongTypes;
 					}
-					err = CallArgumentError_WrongTypes;
 				}
 				score += s;
 			}
@@ -6107,6 +6115,9 @@ gbString write_expr_to_string(gbString str, Ast *node) {
 		if (f->flags&FieldFlag_c_vararg) {
 			str = gb_string_appendc(str, "#c_vararg ");
 		}
+		if (f->flags&FieldFlag_auto_cast) {
+			str = gb_string_appendc(str, "auto_cast ");
+		}
 
 		for_array(i, f->names) {
 			Ast *name = f->names[i];

src/check_type.cpp

@@ -1043,6 +1043,9 @@ Type *check_get_params(CheckerContext *ctx, Scope *scope, Ast *_params, bool *is
 			if (p->flags&FieldFlag_no_alias) {
 				param->flags |= EntityFlag_NoAlias;
 			}
+			if (p->flags&FieldFlag_auto_cast) {
+				param->flags |= EntityFlag_AutoCast;
+			}
 			param->state = EntityState_Resolved; // NOTE(bill): This should have be resolved whilst determining it
 
 			add_entity(ctx->checker, scope, name, param);

src/entity.cpp

@@ -47,6 +47,7 @@ enum EntityFlag {
 	EntityFlag_PolyConst     = 1<<13,
 
 	EntityFlag_CVarArg       = 1<<20,
+	EntityFlag_AutoCast      = 1<<21,
 };
 
 enum EntityState {

src/parser.cpp

@@ -2678,6 +2678,7 @@ enum FieldPrefixKind {
 	FieldPrefix_using,
 	FieldPrefix_no_alias,
 	FieldPrefix_c_var_arg,
+	FieldPrefix_auto_cast,
 	FieldPrefix_in,
 };
 
@@ -2692,6 +2693,9 @@ FieldPrefixKind is_token_field_prefix(AstFile *f) {
 	case Token_in:
 		return FieldPrefix_in;
 
+	case Token_auto_cast:
+		return FieldPrefix_auto_cast;
+
 	case Token_Hash:
 		advance_token(f);
 		switch (f->curr_token.kind) {
@@ -2710,10 +2714,11 @@ FieldPrefixKind is_token_field_prefix(AstFile *f) {
 
 
 u32 parse_field_prefixes(AstFile *f) {
-	i32 using_count    = 0;
-	i32 no_alias_count = 0;
-	i32 c_vararg_count = 0;
-	i32 in_count       = 0;
+	i32 using_count     = 0;
+	i32 no_alias_count  = 0;
+	i32 c_vararg_count  = 0;
+	i32 in_count        = 0;
+	i32 auto_cast_count = 0;
 
 	for (;;) {
 		FieldPrefixKind kind = is_token_field_prefix(f);
@@ -2727,16 +2732,18 @@ u32 parse_field_prefixes(AstFile *f) {
 		}
 
 		switch (kind) {
-		case FieldPrefix_using:     using_count    += 1; advance_token(f); break;
-		case FieldPrefix_no_alias:  no_alias_count += 1; advance_token(f); break;
-		case FieldPrefix_c_var_arg: c_vararg_count += 1; advance_token(f); break;
-		case FieldPrefix_in:        in_count       += 1; advance_token(f); break;
+		case FieldPrefix_using:     using_count     += 1; advance_token(f); break;
+		case FieldPrefix_no_alias:  no_alias_count  += 1; advance_token(f); break;
+		case FieldPrefix_c_var_arg: c_vararg_count  += 1; advance_token(f); break;
+		case FieldPrefix_in:        in_count        += 1; advance_token(f); break;
+		case FieldPrefix_auto_cast: auto_cast_count += 1; advance_token(f); break;
 		}
 	}
 	if (using_count     > 1) syntax_error(f->curr_token, "Multiple 'using' in this field list");
 	if (no_alias_count  > 1) syntax_error(f->curr_token, "Multiple '#no_alias' in this field list");
 	if (c_vararg_count  > 1) syntax_error(f->curr_token, "Multiple '#c_vararg' in this field list");
 	if (in_count        > 1) syntax_error(f->curr_token, "Multiple 'in' in this field list");
+	if (auto_cast_count > 1) syntax_error(f->curr_token, "Multiple 'auto_cast_count' in this field list");
 
 
 	u32 field_flags = 0;
@@ -2744,6 +2751,7 @@ u32 parse_field_prefixes(AstFile *f) {
 	if (no_alias_count  > 0) field_flags |= FieldFlag_no_alias;
 	if (c_vararg_count  > 0) field_flags |= FieldFlag_c_vararg;
 	if (in_count        > 0) field_flags |= FieldFlag_in;
+	if (auto_cast_count > 0) field_flags |= FieldFlag_auto_cast;
 	return field_flags;
 }
 

src/parser.hpp

@@ -177,14 +177,14 @@ enum FieldFlag {
 	FieldFlag_using     = 1<<1,
 	FieldFlag_no_alias  = 1<<2,
 	FieldFlag_c_vararg  = 1<<3,
+	FieldFlag_auto_cast = 1<<4,
 
 	FieldFlag_in        = 1<<5,
 
 
 	FieldFlag_Results   = 1<<16,
 
-	// FieldFlag_Signature = FieldFlag_ellipsis|FieldFlag_using|FieldFlag_no_alias|FieldFlag_c_vararg|FieldFlag_in,
-	FieldFlag_Signature = FieldFlag_ellipsis|FieldFlag_using|FieldFlag_no_alias|FieldFlag_c_vararg,
+	FieldFlag_Signature = FieldFlag_ellipsis|FieldFlag_using|FieldFlag_no_alias|FieldFlag_c_vararg|FieldFlag_auto_cast,
 	FieldFlag_Struct    = FieldFlag_using,
 };