diff --git a/core/_preload.odin b/core/_preload.odin
index 83ce45ce7..953d38c43 100644
--- a/core/_preload.odin
+++ b/core/_preload.odin
@@ -460,11 +460,7 @@ __slice_append :: proc(slice_: rawptr, elem_size, elem_align: int,
 		return slice.count;
 	}
 
-
-	ok := true;
-	if item_count > (slice.capacity-slice.count) {
-		item_count = (slice.capacity-slice.count);
-	}
+	item_count = min(slice.capacity-slice.count, item_count);
 	if item_count > 0 {
 		data := cast(^byte)slice.data;
 		assert(data != nil);
diff --git a/core/fmt.odin b/core/fmt.odin
index eb9233996..eb2353b72 100644
--- a/core/fmt.odin
+++ b/core/fmt.odin
@@ -7,37 +7,20 @@
 
 _BUFFER_SIZE :: 1<<12;
 
-Buffer :: struct {
-	data:   []byte,
-	length: int,
+write_string :: proc(buf: ^[]byte, s: string) {
+	append(buf^, ..cast([]byte)s);
 }
-
-buffer_write :: proc(buf: ^Buffer, b: []byte) {
-	if buf.length < buf.data.count {
-		n := min(buf.data.count-buf.length, b.count);
-		if n > 0 {
-			copy(buf.data[buf.length..], b[..n]);
-			buf.length += n;
-		}
-	}
+write_byte :: proc(buf: ^[]byte, b: byte) {
+	append(buf^, b);
 }
-buffer_write_string :: proc(buf: ^Buffer, s: string) {
-	buffer_write(buf, cast([]byte)s);
-}
-buffer_write_byte :: proc(buf: ^Buffer, b: byte) {
-	if buf.length < buf.data.count {
-		buf.data[buf.length] = b;
-		buf.length++;
-	}
-}
-buffer_write_rune :: proc(buf: ^Buffer, r: rune) {
+write_rune :: proc(buf: ^[]byte, r: rune) {
 	if r < utf8.RUNE_SELF {
-		buffer_write_byte(buf, cast(byte)r);
+		write_byte(buf, cast(byte)r);
 		return;
 	}
 
 	b, n := utf8.encode_rune(r);
-	buffer_write(buf, b[..n]);
+	append(buf^, ..b[..n]);
 }
 
 Fmt_Info :: struct {
@@ -55,7 +38,7 @@ Fmt_Info :: struct {
 	reordered:      bool,
 	good_arg_index: bool,
 
-	buf: ^Buffer,
+	buf: ^[]byte,
 	arg: any, // Temporary
 }
 
@@ -63,25 +46,25 @@ Fmt_Info :: struct {
 
 fprint :: proc(fd: os.Handle, args: ..any) -> int {
 	data: [_BUFFER_SIZE]byte;
-	buf := Buffer{data[..], 0};
+	buf := data[..0];
 	bprint(^buf, ..args);
-	os.write(fd, buf.data[..buf.length]);
-	return buf.length;
+	os.write(fd, buf[..buf.count]);
+	return buf.count;
 }
 
 fprintln :: proc(fd: os.Handle, args: ..any) -> int {
 	data: [_BUFFER_SIZE]byte;
-	buf := Buffer{data[..], 0};
+	buf := data[..0];
 	bprintln(^buf, ..args);
-	os.write(fd, buf.data[..buf.length]);
-	return buf.length;
+	os.write(fd, buf[..buf.count]);
+	return buf.count;
 }
 fprintf :: proc(fd: os.Handle, fmt: string, args: ..any) -> int {
 	data: [_BUFFER_SIZE]byte;
-	buf := Buffer{data[..], 0};
+	buf := data[..0];
 	bprintf(^buf, fmt, ..args);
-	os.write(fd, buf.data[..buf.length]);
-	return buf.length;
+	os.write(fd, buf[..buf.count]);
+	return buf.count;
 }
 
 
@@ -98,12 +81,12 @@ printf :: proc(fmt: string, args: ..any) -> int {
 
 fprint_type :: proc(fd: os.Handle, info: ^Type_Info) {
 	data: [_BUFFER_SIZE]byte;
-	buf := Buffer{data[..], 0};
-	buffer_write_type(^buf, info);
-	os.write(fd, buf.data[..buf.length]);
+	buf := data[..0];
+	write_type(^buf, info);
+	os.write(fd, buf[..buf.count]);
 }
 
-buffer_write_type :: proc(buf: ^Buffer, ti: ^Type_Info) {
+write_type :: proc(buf: ^[]byte, ti: ^Type_Info) {
 	if ti == nil {
 		return;
 	}
@@ -111,131 +94,131 @@ buffer_write_type :: proc(buf: ^Buffer, ti: ^Type_Info) {
 	using Type_Info;
 	match info in ti {
 	case Named:
-		buffer_write_string(buf, info.name);
+		write_string(buf, info.name);
 	case Integer:
 		match {
-		case ti == type_info(int):  buffer_write_string(buf, "int");
-		case ti == type_info(uint): buffer_write_string(buf, "uint");
+		case ti == type_info(int):  write_string(buf, "int");
+		case ti == type_info(uint): write_string(buf, "uint");
 		default:
-			buffer_write_string(buf, info.signed ? "i" : "u");
+			write_string(buf, info.signed ? "i" : "u");
 			fi := Fmt_Info{buf = buf};
 			fmt_int(^fi, cast(u64)(8*info.size), false, 'd');
 		}
 
 	case Float:
 		match info.size {
-		case 4: buffer_write_string(buf, "f32");
-		case 8: buffer_write_string(buf, "f64");
+		case 4: write_string(buf, "f32");
+		case 8: write_string(buf, "f64");
 		}
-	case String:  buffer_write_string(buf, "string");
-	case Boolean: buffer_write_string(buf, "bool");
+	case String:  write_string(buf, "string");
+	case Boolean: write_string(buf, "bool");
 	case Pointer:
 		if info.elem == nil {
-			buffer_write_string(buf, "rawptr");
+			write_string(buf, "rawptr");
 		} else {
-			buffer_write_string(buf, "^");
-			buffer_write_type(buf, info.elem);
+			write_string(buf, "^");
+			write_type(buf, info.elem);
 		}
 	case Procedure:
-		buffer_write_string(buf, "proc");
+		write_string(buf, "proc");
 		if info.params == nil {
-			buffer_write_string(buf, "()");
+			write_string(buf, "()");
 		} else {
 			t := union_cast(^Tuple)info.params;
-			buffer_write_string(buf, "(");
+			write_string(buf, "(");
 			for type, i in t.types {
-				if i > 0 { buffer_write_string(buf, ", "); }
-				buffer_write_type(buf, type);
+				if i > 0 { write_string(buf, ", "); }
+				write_type(buf, type);
 			}
-			buffer_write_string(buf, ")");
+			write_string(buf, ")");
 		}
 		if info.results != nil {
-			buffer_write_string(buf, " -> ");
-			buffer_write_type(buf, info.results);
+			write_string(buf, " -> ");
+			write_type(buf, info.results);
 		}
 	case Tuple:
 		count := info.names.count;
-		if count != 1 { buffer_write_string(buf, "("); }
+		if count != 1 { write_string(buf, "("); }
 		for name, i in info.names {
-			if i > 0 { buffer_write_string(buf, ", "); }
+			if i > 0 { write_string(buf, ", "); }
 
 			type := info.types[i];
 
 			if name.count > 0 {
-				buffer_write_string(buf, name);
-				buffer_write_string(buf, ": ");
+				write_string(buf, name);
+				write_string(buf, ": ");
 			}
-			buffer_write_type(buf, type);
+			write_type(buf, type);
 		}
-		if count != 1 { buffer_write_string(buf, ")"); }
+		if count != 1 { write_string(buf, ")"); }
 
 	case Array:
-		buffer_write_string(buf, "[");
+		write_string(buf, "[");
 		fi := Fmt_Info{buf = buf};
 		fmt_int(^fi, cast(u64)info.count, false, 'd');
-		buffer_write_string(buf, "]");
-		buffer_write_type(buf, info.elem);
+		write_string(buf, "]");
+		write_type(buf, info.elem);
 	case Dynamic_Array:
-		buffer_write_string(buf, "[..]");
-		buffer_write_type(buf, info.elem);
+		write_string(buf, "[..]");
+		write_type(buf, info.elem);
 	case Slice:
-		buffer_write_string(buf, "[");
-		buffer_write_string(buf, "]");
-		buffer_write_type(buf, info.elem);
+		write_string(buf, "[");
+		write_string(buf, "]");
+		write_type(buf, info.elem);
 	case Vector:
-		buffer_write_string(buf, "[vector ");
+		write_string(buf, "[vector ");
 		fi := Fmt_Info{buf = buf};
 		fmt_int(^fi, cast(u64)info.count, false, 'd');
-		buffer_write_string(buf, "]");
-		buffer_write_type(buf, info.elem);
+		write_string(buf, "]");
+		write_type(buf, info.elem);
 
 	case Map:
-		buffer_write_string(buf, "map[");
-		buffer_write_type(buf, info.key);
-		buffer_write_byte(buf, ']');
-		buffer_write_type(buf, info.value);
+		write_string(buf, "map[");
+		write_type(buf, info.key);
+		write_byte(buf, ']');
+		write_type(buf, info.value);
 
 	case Struct:
-		buffer_write_string(buf, "struct ");
-		if info.packed  { buffer_write_string(buf, "#packed "); }
-		if info.ordered { buffer_write_string(buf, "#ordered "); }
+		write_string(buf, "struct ");
+		if info.packed  { write_string(buf, "#packed "); }
+		if info.ordered { write_string(buf, "#ordered "); }
 		if info.custom_align {
-			buffer_write_string(buf, "#align ");
+			write_string(buf, "#align ");
 			fi := Fmt_Info{buf = buf};
 			fmt_int(^fi, cast(u64)info.align, false, 'd');
-			buffer_write_byte(buf, ' ');
+			write_byte(buf, ' ');
 		}
-		buffer_write_byte(buf, '{');
+		write_byte(buf, '{');
 		for name, i in info.names {
 			if i > 0 {
-				buffer_write_string(buf, ", ");
+				write_string(buf, ", ");
 			}
-			buffer_write_string(buf, name);
-			buffer_write_string(buf, ": ");
-			buffer_write_type(buf, info.types[i]);
+			write_string(buf, name);
+			write_string(buf, ": ");
+			write_type(buf, info.types[i]);
 		}
-		buffer_write_byte(buf, '}');
+		write_byte(buf, '}');
 
 	case Union:
-		buffer_write_string(buf, "union {");
+		write_string(buf, "union {");
 		cf := info.common_fields;
 		total_count := 0;
 		for name, i in cf.names {
 			if i > 0 {
-				buffer_write_string(buf, ", ");
+				write_string(buf, ", ");
 			}
-			buffer_write_string(buf, name);
-			buffer_write_string(buf, ": ");
-			buffer_write_type(buf, cf.types[i]);
+			write_string(buf, name);
+			write_string(buf, ": ");
+			write_type(buf, cf.types[i]);
 			total_count++;
 		}
 		for name, i in info.variant_names {
 			if total_count > 0 || i > 0 {
-				buffer_write_string(buf, ", ");
+				write_string(buf, ", ");
 			}
-			buffer_write_string(buf, name);
-			buffer_write_byte(buf, '{');
-			defer buffer_write_byte(buf, '}');
+			write_string(buf, name);
+			write_byte(buf, '{');
+			defer write_byte(buf, '}');
 
 			variant_type := type_info_base(info.variant_types[i]);
 			variant := union_cast(^Struct)variant_type;
@@ -243,44 +226,44 @@ buffer_write_type :: proc(buf: ^Buffer, ti: ^Type_Info) {
 			vc := variant.names.count-cf.names.count;
 			for j in 0..vc {
 				if j > 0 {
-					buffer_write_string(buf, ", ");
+					write_string(buf, ", ");
 				}
 				index := j + cf.names.count;
-				buffer_write_string(buf, variant.names[index]);
-				buffer_write_string(buf, ": ");
-				buffer_write_type(buf, variant.types[index]);
+				write_string(buf, variant.names[index]);
+				write_string(buf, ": ");
+				write_type(buf, variant.types[index]);
 			}
 		}
-		buffer_write_string(buf, "}");
+		write_string(buf, "}");
 
 	case Raw_Union:
-		buffer_write_string(buf, "raw_union {");
+		write_string(buf, "raw_union {");
 		for name, i in info.names {
 			if i > 0 {
-				buffer_write_string(buf, ", ");
+				write_string(buf, ", ");
 			}
-			buffer_write_string(buf, name);
-			buffer_write_string(buf, ": ");
-			buffer_write_type(buf, info.types[i]);
+			write_string(buf, name);
+			write_string(buf, ": ");
+			write_type(buf, info.types[i]);
 		}
-		buffer_write_string(buf, "}");
+		write_string(buf, "}");
 
 	case Enum:
-		buffer_write_string(buf, "enum ");
-		buffer_write_type(buf, info.base);
-		buffer_write_string(buf, " {");
+		write_string(buf, "enum ");
+		write_type(buf, info.base);
+		write_string(buf, " {");
 		for name, i in info.names {
 			if i > 0 {
-				buffer_write_string(buf, ", ");
+				write_string(buf, ", ");
 			}
-			buffer_write_string(buf, name);
+			write_string(buf, name);
 		}
-		buffer_write_string(buf, "}");
+		write_string(buf, "}");
 	}
 }
 
 
-bprint :: proc(buf: ^Buffer, args: ..any) -> int {
+bprint :: proc(buf: ^[]byte, args: ..any) -> int {
 	fi: Fmt_Info;
 	fi.buf = buf;
 
@@ -288,45 +271,39 @@ bprint :: proc(buf: ^Buffer, args: ..any) -> int {
 	for arg, i in args {
 		is_string := arg.data != nil && types.is_string(arg.type_info);
 		if i > 0 && !is_string && !prev_string {
-			buffer_write_byte(buf, ' ');
+			write_byte(buf, ' ');
 		}
 		fmt_value(^fi, args[i], 'v');
 		prev_string = is_string;
 	}
-	return buf.length;
+	return buf.count;
 }
 
-bprintln :: proc(buf: ^Buffer, args: ..any) -> int {
+bprintln :: proc(buf: ^[]byte, args: ..any) -> int {
 	fi: Fmt_Info;
 	fi.buf = buf;
 
 	for arg, i in args {
 		if i > 0 {
-			buffer_write_byte(buf, ' ');
+			write_byte(buf, ' ');
 		}
 		fmt_value(^fi, args[i], 'v');
 	}
-	buffer_write_byte(buf, '\n');
-	return buf.length;
+	write_byte(buf, '\n');
+	return buf.count;
 }
 
 sprint :: proc(buf: []byte, args: ..any) -> string {
-	b: Buffer;
-	b.data = buf;
-	count := bprint(^b, ..args);
-	return cast(string)b.data[..b.length];
+	count := bprint(^buf, ..args);
+	return cast(string)buf;
 }
 sprintln :: proc(buf: []byte, args: ..any) -> string {
-	b: Buffer;
-	b.data = buf;
-	count := bprintln(^b, ..args);
-	return cast(string)b.data[..b.length];
+	count := bprintln(^buf, ..args);
+	return cast(string)buf;
 }
 sprintf :: proc(buf: []byte, fmt: string, args: ..any) -> string {
-	b: Buffer;
-	b.data = buf;
-	count := bprintf(^b, fmt, ..args);
-	return cast(string)b.data[..b.length];
+	count := bprintf(^buf, fmt, ..args);
+	return cast(string)buf;
 }
 
 
@@ -420,23 +397,23 @@ int_from_arg :: proc(args: []any, arg_index: int) -> (int, int, bool) {
 
 fmt_bad_verb :: proc(using fi: ^Fmt_Info, verb: rune) {
 	assert(verb != 'v');
-	buffer_write_string(buf, "%!");
-	buffer_write_rune(buf, verb);
-	buffer_write_byte(buf, '(');
+	write_string(buf, "%!");
+	write_rune(buf, verb);
+	write_byte(buf, '(');
 	if arg.type_info != nil {
-		buffer_write_type(buf, arg.type_info);
-		buffer_write_byte(buf, '=');
+		write_type(buf, arg.type_info);
+		write_byte(buf, '=');
 		fmt_value(fi, arg, 'v');
 	} else {
-		buffer_write_string(buf, "<nil>");
+		write_string(buf, "<nil>");
 	}
-	buffer_write_byte(buf, ')');
+	write_byte(buf, ')');
 }
 
 fmt_bool :: proc(using fi: ^Fmt_Info, b: bool, verb: rune) {
 	match verb {
 	case 't', 'v':
-		buffer_write_string(buf, b ? "true" : "false");
+		write_string(buf, b ? "true" : "false");
 	default:
 		fmt_bad_verb(fi, verb);
 	}
@@ -452,12 +429,10 @@ fmt_write_padding :: proc(fi: ^Fmt_Info, width: int) {
 		pad_byte = '0';
 	}
 
-	count := min(width, fi.buf.data.count-fi.buf.length);
-	start := fi.buf.length;
-	for i in start..count {
-		fi.buf.data[i] = pad_byte;
+	count := min(width, fi.buf.capacity-fi.buf.count);
+	for _ in 0..count {
+		append(fi.buf^, pad_byte);
 	}
-	fi.buf.length += count;
 }
 
 _write_int :: proc(fi: ^Fmt_Info, u: u64, base: int, neg: bool, digits: string) {
@@ -503,7 +478,7 @@ _write_int :: proc(fi: ^Fmt_Info, u: u64, base: int, neg: bool, digits: string)
 	if fi.hash  { flags |= strconv.Int_Flag.PREFIX; }
 	if fi.plus  { flags |= strconv.Int_Flag.PLUS; }
 	if fi.space { flags |= strconv.Int_Flag.SPACE; }
-	s := strconv.format_bits(buf[..], u, base, neg, digits, flags);
+	s := strconv.append_bits(buf[..0], u, base, neg, digits, flags);
 
 	prev_zero := fi.zero;
 	defer fi.zero = prev_zero;
@@ -515,7 +490,7 @@ immutable __DIGITS_LOWER := "0123456789abcdefx";
 immutable __DIGITS_UPPER := "0123456789ABCDEFX";
 
 fmt_rune :: proc(fi: ^Fmt_Info, r: rune) {
-	buffer_write_rune(fi.buf, r);
+	write_rune(fi.buf, r);
 }
 
 fmt_int :: proc(fi: ^Fmt_Info, u: u64, neg: bool, verb: rune) {
@@ -533,7 +508,7 @@ fmt_int :: proc(fi: ^Fmt_Info, u: u64, neg: bool, verb: rune) {
 		if r < 0 || r > utf8.MAX_RUNE {
 			fmt_bad_verb(fi, verb);
 		} else {
-			buffer_write_string(fi.buf, "U+");
+			write_string(fi.buf, "U+");
 			_write_int(fi, u, 16, false, __DIGITS_UPPER);
 		}
 
@@ -544,16 +519,16 @@ fmt_int :: proc(fi: ^Fmt_Info, u: u64, neg: bool, verb: rune) {
 
 _pad :: proc(fi: ^Fmt_Info, s: string) {
 	if !fi.width_set || fi.width == 0 {
-		buffer_write_string(fi.buf, s);
+		write_string(fi.buf, s);
 		return;
 	}
 	width := fi.width - utf8.rune_count(s);
 	if fi.minus { // right pad
-		buffer_write_string(fi.buf, s);
+		write_string(fi.buf, s);
 		fmt_write_padding(fi, width);
 	} else { // left pad
 		fmt_write_padding(fi, width);
-		buffer_write_string(fi.buf, s);
+		write_string(fi.buf, s);
 	}
 }
 
@@ -570,7 +545,7 @@ fmt_float :: proc(fi: ^Fmt_Info, v: f64, bit_size: int, verb: rune) {
 			prec = fi.prec;
 		}
 		buf: [128]byte;
-		str := strconv.format_float(buf[1..], v, 'f', prec, bit_size);
+		str := strconv.append_float(buf[1..1], v, 'f', prec, bit_size);
 		str = cast(string)buf[..str.count+1];
 		if str[1] == '+' || str[1] == '-' {
 			str = str[1..];
@@ -583,15 +558,15 @@ fmt_float :: proc(fi: ^Fmt_Info, v: f64, bit_size: int, verb: rune) {
 		}
 
 		if str[1] == 'N' && str[1] == 'I' {
-			buffer_write_string(fi.buf, str);
+			write_string(fi.buf, str);
 			return;
 		}
 
 		if fi.plus || str[0] != '+' {
 			if fi.zero && fi.width_set && fi.width > str.count {
-				buffer_write_byte(fi.buf, str[0]);
+				write_byte(fi.buf, str[0]);
 				fmt_write_padding(fi, fi.width - str.count);
-				buffer_write_string(fi.buf, str[1..]);
+				write_string(fi.buf, str[1..]);
 			} else {
 				_pad(fi, str);
 			}
@@ -607,7 +582,7 @@ fmt_float :: proc(fi: ^Fmt_Info, v: f64, bit_size: int, verb: rune) {
 fmt_string :: proc(fi: ^Fmt_Info, s: string, verb: rune) {
 	match verb {
 	case 's', 'v':
-		buffer_write_string(fi.buf, s);
+		write_string(fi.buf, s);
 	default:
 		fmt_bad_verb(fi, verb);
 	}
@@ -623,14 +598,14 @@ fmt_pointer :: proc(fi: ^Fmt_Info, p: rawptr, verb: rune) {
 	}
 	u := cast(u64)cast(uint)p;
 	if !fi.hash || verb == 'v' {
-		buffer_write_string(fi.buf, "0x");
+		write_string(fi.buf, "0x");
 	}
 	_write_int(fi, u, 16, false, __DIGITS_UPPER);
 }
 
 fmt_enum :: proc(fi: ^Fmt_Info, v: any, verb: rune) {
 	if v.type_info == nil || v.data == nil {
-		buffer_write_string(fi.buf, "<nil>");
+		write_string(fi.buf, "<nil>");
 		return;
 	}
 
@@ -666,18 +641,18 @@ fmt_enum :: proc(fi: ^Fmt_Info, v: any, verb: rune) {
 			if types.is_string(e.base) {
 				for val, idx in e.values {
 					if val.i == i {
-						buffer_write_string(fi.buf, e.names[idx]);
+						write_string(fi.buf, e.names[idx]);
 						ok = true;
 						break;
 					}
 				}
 			} else if e.values.count == 0 {
-				buffer_write_string(fi.buf, "");
+				write_string(fi.buf, "");
 				ok = true;
 			} else {
 				for val, idx in e.values {
 					if val.i == i {
-						buffer_write_string(fi.buf, e.names[idx]);
+						write_string(fi.buf, e.names[idx]);
 						ok = true;
 						break;
 					}
@@ -685,7 +660,7 @@ fmt_enum :: proc(fi: ^Fmt_Info, v: any, verb: rune) {
 			}
 
 			if !ok {
-				buffer_write_string(fi.buf, "!%(BAD ENUM VALUE)");
+				write_string(fi.buf, "!%(BAD ENUM VALUE)");
 			}
 		default:
 			fmt_bad_verb(fi, verb);
@@ -697,7 +672,7 @@ fmt_enum :: proc(fi: ^Fmt_Info, v: any, verb: rune) {
 
 fmt_value :: proc(fi: ^Fmt_Info, v: any, verb: rune) {
 	if v.data == nil || v.type_info == nil {
-		buffer_write_string(fi.buf, "<nil>");
+		write_string(fi.buf, "<nil>");
 		return;
 	}
 
@@ -710,18 +685,18 @@ fmt_value :: proc(fi: ^Fmt_Info, v: any, verb: rune) {
 				fmt_bad_verb(fi, verb);
 				return;
 			}
-			buffer_write_string(fi.buf, info.name);
-			buffer_write_byte(fi.buf, '{');
+			write_string(fi.buf, info.name);
+			write_byte(fi.buf, '{');
 			for _, i in b.names {
 				if i > 0 {
-					buffer_write_string(fi.buf, ", ");
+					write_string(fi.buf, ", ");
 				}
-				buffer_write_string(fi.buf, b.names[i]);
-				buffer_write_string(fi.buf, " = ");
+				write_string(fi.buf, b.names[i]);
+				write_string(fi.buf, " = ");
 				data := cast(^byte)v.data + b.offsets[i];
 				fmt_arg(fi, any{b.types[i], cast(rawptr)data}, 'v');
 			}
-			buffer_write_byte(fi.buf, '}');
+			write_byte(fi.buf, '}');
 
 		default:
 			fmt_value(fi, any{info.base, v.data}, verb);
@@ -734,7 +709,7 @@ fmt_value :: proc(fi: ^Fmt_Info, v: any, verb: rune) {
 
 	case Pointer:
 		if v.type_info == type_info(^Type_Info) {
-			buffer_write_type(fi.buf, (cast(^^Type_Info)v.data)^);
+			write_type(fi.buf, (cast(^^Type_Info)v.data)^);
 		} else {
 			fmt_pointer(fi, (cast(^rawptr)v.data)^, verb);
 		}
@@ -745,11 +720,11 @@ fmt_value :: proc(fi: ^Fmt_Info, v: any, verb: rune) {
 			return;
 		}
 
-		buffer_write_byte(fi.buf, '[');
-		defer buffer_write_byte(fi.buf, ']');
+		write_byte(fi.buf, '[');
+		defer write_byte(fi.buf, ']');
 		for i in 0..info.count {
 			if i > 0 {
-				buffer_write_string(fi.buf, ", ");
+				write_string(fi.buf, ", ");
 			}
 			data := cast(^byte)v.data + i*info.elem_size;
 			fmt_arg(fi, any{info.elem, cast(rawptr)data}, 'v');
@@ -761,12 +736,12 @@ fmt_value :: proc(fi: ^Fmt_Info, v: any, verb: rune) {
 			return;
 		}
 
-		buffer_write_byte(fi.buf, '[');
-		defer buffer_write_byte(fi.buf, ']');
+		write_byte(fi.buf, '[');
+		defer write_byte(fi.buf, ']');
 		array := cast(^Raw_Dynamic_Array)v.data;
 		for i in 0..array.count {
 			if i > 0 {
-				buffer_write_string(fi.buf, ", ");
+				write_string(fi.buf, ", ");
 			}
 			data := cast(^byte)array.data + i*info.elem_size;
 			fmt_arg(fi, any{info.elem, cast(rawptr)data}, 'v');
@@ -778,8 +753,8 @@ fmt_value :: proc(fi: ^Fmt_Info, v: any, verb: rune) {
 			return;
 		}
 
-		buffer_write_string(fi.buf, "map[");
-		defer buffer_write_byte(fi.buf, ']');
+		write_string(fi.buf, "map[");
+		defer write_byte(fi.buf, ']');
 		entries := ^(cast(^Raw_Dynamic_Map)v.data).entries;
 		gs := union_cast(^Struct)type_info_base(info.generated_struct);
 		ed := union_cast(^Dynamic_Array)type_info_base(gs.types[1]);
@@ -788,19 +763,19 @@ fmt_value :: proc(fi: ^Fmt_Info, v: any, verb: rune) {
 		entry_size := ed.elem_size;
 		for i in 0..entries.count {
 			if i > 0 {
-				buffer_write_string(fi.buf, ", ");
+				write_string(fi.buf, ", ");
 			}
 			data := cast(^byte)entries.data + i*entry_size;
 
 			header := cast(^__Map_Entry_Header)data;
 			if types.is_string(info.key) {
-				buffer_write_string(fi.buf, header.key.str);
+				write_string(fi.buf, header.key.str);
 			} else {
 				fi := Fmt_Info{buf = fi.buf};
 				fmt_arg(^fi, any{info.key, cast(rawptr)^header.key.hash}, 'v');
 			}
 
-			buffer_write_string(fi.buf, "=");
+			write_string(fi.buf, "=");
 
 			value := data + entry_type.offsets[2];
 			fmt_arg(fi, any{info.value, cast(rawptr)value}, 'v');
@@ -812,24 +787,24 @@ fmt_value :: proc(fi: ^Fmt_Info, v: any, verb: rune) {
 			return;
 		}
 
-		buffer_write_byte(fi.buf, '[');
-		defer buffer_write_byte(fi.buf, ']');
+		write_byte(fi.buf, '[');
+		defer write_byte(fi.buf, ']');
 		slice := cast(^[]byte)v.data;
 		for i in 0..slice.count {
 			if i > 0 {
-				buffer_write_string(fi.buf, ", ");
+				write_string(fi.buf, ", ");
 			}
 			data := slice.data + i*info.elem_size;
 			fmt_arg(fi, any{info.elem, cast(rawptr)data}, 'v');
 		}
 
 	case Vector:
-		buffer_write_byte(fi.buf, '<');
-		defer buffer_write_byte(fi.buf, '>');
+		write_byte(fi.buf, '<');
+		defer write_byte(fi.buf, '>');
 
 		for i in 0..info.count {
 			if i > 0 {
-				buffer_write_string(fi.buf, ", ");
+				write_string(fi.buf, ", ");
 			}
 
 			data := cast(^byte)v.data + i*info.elem_size;
@@ -837,51 +812,51 @@ fmt_value :: proc(fi: ^Fmt_Info, v: any, verb: rune) {
 		}
 
 	case Struct:
-		buffer_write_byte(fi.buf, '{');
-		defer buffer_write_byte(fi.buf, '}');
+		write_byte(fi.buf, '{');
+		defer write_byte(fi.buf, '}');
 
 		for _, i in info.names {
 			if i > 0 {
-				buffer_write_string(fi.buf, ", ");
+				write_string(fi.buf, ", ");
 			}
-			buffer_write_string(fi.buf, info.names[i]);
-			buffer_write_string(fi.buf, " = ");
+			write_string(fi.buf, info.names[i]);
+			write_string(fi.buf, " = ");
 			data := cast(^byte)v.data + info.offsets[i];
 			fmt_value(fi, any{info.types[i], cast(rawptr)data}, 'v');
 		}
 
 	case Union:
-		buffer_write_byte(fi.buf, '{');
-		defer buffer_write_byte(fi.buf, '}');
+		write_byte(fi.buf, '{');
+		defer write_byte(fi.buf, '}');
 
 		cf := info.common_fields;
 
 		for _, i in cf.names {
 			if i > 0 {
-				buffer_write_string(fi.buf, ", ");
+				write_string(fi.buf, ", ");
 			}
-			buffer_write_string(fi.buf, cf.names[i]);
-			buffer_write_string(fi.buf, " = ");
+			write_string(fi.buf, cf.names[i]);
+			write_string(fi.buf, " = ");
 			data := cast(^byte)v.data + cf.offsets[i];
 			fmt_value(fi, any{cf.types[i], cast(rawptr)data}, 'v');
 		}
 
 	case Raw_Union:
-		buffer_write_string(fi.buf, "(raw_union)");
+		write_string(fi.buf, "(raw_union)");
 
 	case Enum:
 		fmt_enum(fi, v, verb);
 
 	case Procedure:
-		buffer_write_type(fi.buf, v.type_info);
-		buffer_write_string(fi.buf, " @ ");
+		write_type(fi.buf, v.type_info);
+		write_string(fi.buf, " @ ");
 		fmt_pointer(fi, (cast(^rawptr)v.data)^, 'p');
 	}
 }
 
 fmt_arg :: proc(fi: ^Fmt_Info, arg: any, verb: rune) {
 	if arg.data == nil || arg.type_info == nil {
-		buffer_write_string(fi.buf, "<nil>");
+		write_string(fi.buf, "<nil>");
 		return;
 	}
 	fi.arg = arg;
@@ -891,7 +866,7 @@ fmt_arg :: proc(fi: ^Fmt_Info, arg: any, verb: rune) {
 		match a in arg {
 		case ^Type_Info: ti = a;
 		}
-		buffer_write_type(fi.buf, ti);
+		write_type(fi.buf, ti);
 		return;
 	}
 
@@ -920,7 +895,7 @@ fmt_arg :: proc(fi: ^Fmt_Info, arg: any, verb: rune) {
 }
 
 
-bprintf :: proc(b: ^Buffer, fmt: string, args: ..any) -> int {
+bprintf :: proc(b: ^[]byte, fmt: string, args: ..any) -> int {
 	fi := Fmt_Info{};
 	end := fmt.count;
 	arg_index := 0;
@@ -933,7 +908,7 @@ bprintf :: proc(b: ^Buffer, fmt: string, args: ..any) -> int {
 			i++;
 		}
 		if i > prev_i {
-			buffer_write_string(b, fmt[prev_i..i]);
+			write_string(b, fmt[prev_i..i]);
 		}
 		if i >= end {
 			break;
@@ -974,7 +949,7 @@ bprintf :: proc(b: ^Buffer, fmt: string, args: ..any) -> int {
 			i++;
 			fi.width, arg_index, fi.width_set = int_from_arg(args, arg_index);
 			if !fi.width_set {
-				buffer_write_string(b, "%!(BAD WIDTH)");
+				write_string(b, "%!(BAD WIDTH)");
 			}
 
 			if fi.width < 0 {
@@ -1005,7 +980,7 @@ bprintf :: proc(b: ^Buffer, fmt: string, args: ..any) -> int {
 					fi.prec_set = false;
 				}
 				if !fi.prec_set {
-					buffer_write_string(fi.buf, "%!(BAD PRECISION)");
+					write_string(fi.buf, "%!(BAD PRECISION)");
 				}
 				was_prev_index = false;
 			} else {
@@ -1022,7 +997,7 @@ bprintf :: proc(b: ^Buffer, fmt: string, args: ..any) -> int {
 		}
 
 		if i >= end {
-			buffer_write_string(b, "%!(NO VERB)");
+			write_string(b, "%!(NO VERB)");
 			break;
 		}
 
@@ -1030,11 +1005,11 @@ bprintf :: proc(b: ^Buffer, fmt: string, args: ..any) -> int {
 		i += w;
 
 		if verb == '%' {
-			buffer_write_byte(b, '%');
+			write_byte(b, '%');
 		} else if !fi.good_arg_index {
-			buffer_write_string(b, "%!(BAD ARGUMENT NUMBER)");
+			write_string(b, "%!(BAD ARGUMENT NUMBER)");
 		} else if arg_index >= args.count {
-			buffer_write_string(b, "%!(MISSING ARGUMENT)");
+			write_string(b, "%!(MISSING ARGUMENT)");
 		} else {
 			fmt_arg(^fi, args[arg_index], verb);
 			arg_index++;
@@ -1042,19 +1017,19 @@ bprintf :: proc(b: ^Buffer, fmt: string, args: ..any) -> int {
 	}
 
 	if !fi.reordered && arg_index < args.count {
-		buffer_write_string(b, "%!(EXTRA ");
+		write_string(b, "%!(EXTRA ");
 		for arg, index in args[arg_index..] {
 			if index > 0 {
-				buffer_write_string(b, ", ");
+				write_string(b, ", ");
 			}
 			if arg.data == nil || arg.type_info == nil {
-				buffer_write_string(b, "<nil>");
+				write_string(b, "<nil>");
 			} else {
 				fmt_arg(^fi, args[index], 'v');
 			}
 		}
-		buffer_write_string(b, ")");
+		write_string(b, ")");
 	}
 
-	return b.length;
+	return b.count;
 }
diff --git a/core/strconv.odin b/core/strconv.odin
index 57090cba9..ff78847df 100644
--- a/core/strconv.odin
+++ b/core/strconv.odin
@@ -18,24 +18,24 @@ parse_bool :: proc(s: string) -> (result: bool, ok: bool) {
 	return false, false;
 }
 
-format_bool :: proc(buf: []byte, b: bool) -> string {
+append_bool :: proc(buf: []byte, b: bool) -> string {
 	s := b ? "true" : "false";
-	len := copy(buf, cast([]byte)s);
-	return cast(string)buf[..len];
+	append(buf, ..cast([]byte)s);
+	return cast(string)buf;
 }
 
-format_uint :: proc(buf: []byte, u: u64, base: int) -> string {
+append_uint :: proc(buf: []byte, u: u64, base: int) -> string {
 	using Int_Flag;
-	return format_bits(buf, u, base, false, digits, 0);
+	return append_bits(buf, u, base, false, digits, 0);
 }
-format_int :: proc(buf: []byte, i: i64, base: int) -> string {
-	return format_bits(buf, cast(u64)i, base, i < 0, digits, 0);
+append_int :: proc(buf: []byte, i: i64, base: int) -> string {
+	return append_bits(buf, cast(u64)i, base, i < 0, digits, 0);
 }
 itoa :: proc(buf: []byte, i: int) -> string {
-	return format_int(buf, cast(i64)i, 10);
+	return append_int(buf, cast(i64)i, 10);
 }
 
-format_float :: proc(buf: []byte, f: f64, fmt: byte, prec, bit_size: int) -> string {
+append_float :: proc(buf: []byte, f: f64, fmt: byte, prec, bit_size: int) -> string {
 	return cast(string)generic_ftoa(buf, f, fmt, prec, bit_size);
 }
 
@@ -87,8 +87,8 @@ generic_ftoa :: proc(buf: []byte, val: f64, fmt: byte, prec, bit_size: int) -> [
 		} else {
 			s = "+Inf";
 		}
-		len := copy(buf, cast([]byte)s);
-		return buf[..len];
+		append(buf, ..cast([]byte)s);
+		return buf;
 
 	case 0: // denormalized
 		exp++;
@@ -190,8 +190,8 @@ format_digits :: proc(buf: []byte, shortest: bool, neg: bool, digs: Decimal_Slic
 	c: [2]byte;
 	c[0] = '%';
 	c[1] = fmt;
-	len := copy(buf, ..c[..]);
-	return buf[..len];
+	append(buf, ..c[..]);
+	return buf;
 }
 
 round_shortest :: proc(d: ^Decimal, mant: u64, exp: int, flt: ^Float_Info) {
@@ -265,7 +265,7 @@ MAX_BASE :: 32;
 immutable digits := "0123456789abcdefghijklmnopqrstuvwxyz";
 
 
-format_bits :: proc(buf: []byte, u: u64, base: int, neg: bool, digits: string, flags: Int_Flag) -> string {
+append_bits :: proc(buf: []byte, u: u64, base: int, neg: bool, digits: string, flags: Int_Flag) -> string {
 	is_pow2 :: proc(x: i64) -> bool {
 		if (x <= 0) {
 			return false;
@@ -274,7 +274,7 @@ format_bits :: proc(buf: []byte, u: u64, base: int, neg: bool, digits: string, f
 	}
 
 	if base < 2 || base > MAX_BASE {
-		panic("strconv: illegal base passed to format_bits");
+		panic("strconv: illegal base passed to append_bits");
 	}
 
 	a: [65]byte;
@@ -330,7 +330,7 @@ format_bits :: proc(buf: []byte, u: u64, base: int, neg: bool, digits: string, f
 	}
 
 
-	len := copy(buf, ..a[i..]);
-	return cast(string)buf[..len];
+	append(buf, ..a[i..]);
+	return cast(string)buf;
 }
 
diff --git a/src/check_expr.c b/src/check_expr.c
index 264a5d072..0e166ef1a 100644
--- a/src/check_expr.c
+++ b/src/check_expr.c
@@ -5127,6 +5127,10 @@ ExprKind check__expr_base(Checker *c, Operand *o, AstNode *node, Type *type_hint
 		switch (t->kind) {
 		case Type_Basic:
 			if (is_type_string(t)) {
+				if (se->index3) {
+					error_node(node, "3-index slice on a string in not needed");
+					goto error;
+				}
 				valid = true;
 				if (o->mode == Addressing_Constant) {
 					max_count = o->value.value_string.len;
@@ -5167,14 +5171,20 @@ ExprKind check__expr_base(Checker *c, Operand *o, AstNode *node, Type *type_hint
 			o->mode = Addressing_Value;
 		}
 
+		if (se->index3 && (se->high == NULL || se->max == NULL)) {
+			error(se->close, "2nd and 3rd indices are required in a 3-index slice");
+			goto error;
+		}
+
 		i64 indices[2] = {0};
-		AstNode *nodes[2] = {se->low, se->high};
+		AstNode *nodes[3] = {se->low, se->high, se->max};
 		for (isize i = 0; i < gb_count_of(nodes); i++) {
 			i64 index = max_count;
 			if (nodes[i] != NULL) {
 				i64 capacity = -1;
-				if (max_count >= 0)
+				if (max_count >= 0) {
 					capacity = max_count;
+				}
 				i64 j = 0;
 				if (check_index_value(c, nodes[i], capacity, &j)) {
 					index = j;