diff --git a/src-self-hosted/dep_tokenizer.zig b/src-self-hosted/dep_tokenizer.zig
index 11724a3d2c..233b678171 100644
--- a/src-self-hosted/dep_tokenizer.zig
+++ b/src-self-hosted/dep_tokenizer.zig
@@ -306,12 +306,12 @@ pub const Tokenizer = struct {
 
     fn errorPosition(self: *Tokenizer, position: usize, bytes: []const u8, comptime fmt: []const u8, args: var) Error {
         var buffer = try std.Buffer.initSize(&self.arena.allocator, 0);
-        std.fmt.format(&buffer, anyerror, std.Buffer.append, fmt, args) catch {};
+        try buffer.print(fmt, args);
         try buffer.append(" '");
         var out = makeOutput(std.Buffer.append, &buffer);
         try printCharValues(&out, bytes);
         try buffer.append("'");
-        std.fmt.format(&buffer, anyerror, std.Buffer.append, " at position {}", .{position - (bytes.len - 1)}) catch {};
+        try buffer.print(" at position {}", .{position - (bytes.len - 1)});
         self.error_text = buffer.toSlice();
         return Error.InvalidInput;
     }
@@ -319,10 +319,9 @@ pub const Tokenizer = struct {
     fn errorIllegalChar(self: *Tokenizer, position: usize, char: u8, comptime fmt: []const u8, args: var) Error {
         var buffer = try std.Buffer.initSize(&self.arena.allocator, 0);
         try buffer.append("illegal char ");
-        var out = makeOutput(std.Buffer.append, &buffer);
-        try printUnderstandableChar(&out, char);
-        std.fmt.format(&buffer, anyerror, std.Buffer.append, " at position {}", .{position}) catch {};
-        if (fmt.len != 0) std.fmt.format(&buffer, anyerror, std.Buffer.append, ": " ++ fmt, args) catch {};
+        try printUnderstandableChar(&buffer, char);
+        try buffer.print(" at position {}", .{position});
+        if (fmt.len != 0) try buffer.print(": " ++ fmt, args);
         self.error_text = buffer.toSlice();
         return Error.InvalidInput;
     }
@@ -980,13 +979,13 @@ fn hexDump16(out: var, offset: usize, bytes: []const u8) !void {
 
 fn printDecValue(out: var, value: u64, width: u8) !void {
     var buffer: [20]u8 = undefined;
-    const len = std.fmt.formatIntBuf(buffer[0..], value, 10, false, width);
+    const len = std.fmtstream.formatIntBuf(buffer[0..], value, 10, false, width);
     try out.write(buffer[0..len]);
 }
 
 fn printHexValue(out: var, value: u64, width: u8) !void {
     var buffer: [16]u8 = undefined;
-    const len = std.fmt.formatIntBuf(buffer[0..], value, 16, false, width);
+    const len = std.fmtstream.formatIntBuf(buffer[0..], value, 16, false, width);
     try out.write(buffer[0..len]);
 }
 
@@ -996,14 +995,13 @@ fn printCharValues(out: var, bytes: []const u8) !void {
     }
 }
 
-fn printUnderstandableChar(out: var, char: u8) !void {
+fn printUnderstandableChar(buffer: *std.Buffer, char: u8) !void {
     if (!std.ascii.isPrint(char) or char == ' ') {
-        const output = @typeInfo(@TypeOf(out)).Pointer.child.output;
-        std.fmt.format(out.context, anyerror, output, "\\x{X:2}", .{char}) catch {};
+        try buffer.print("\\x{X:2}", .{char});
     } else {
-        try out.write("'");
-        try out.write(&[_]u8{printable_char_tab[char]});
-        try out.write("'");
+        try buffer.append("'");
+        try buffer.appendByte(printable_char_tab[char]);
+        try buffer.append("'");
     }
 }
 
diff --git a/test/stage1/behavior/enum_with_members.zig b/test/stage1/behavior/enum_with_members.zig
index 08b195494b..b299301ced 100644
--- a/test/stage1/behavior/enum_with_members.zig
+++ b/test/stage1/behavior/enum_with_members.zig
@@ -1,6 +1,6 @@
 const expect = @import("std").testing.expect;
 const mem = @import("std").mem;
-const fmt = @import("std").fmt;
+const fmtstream = @import("std").fmtstream;
 
 const ET = union(enum) {
     SINT: i32,
@@ -8,8 +8,8 @@ const ET = union(enum) {
 
     pub fn print(a: *const ET, buf: []u8) anyerror!usize {
         return switch (a.*) {
-            ET.SINT => |x| fmt.formatIntBuf(buf, x, 10, false, fmt.FormatOptions{}),
-            ET.UINT => |x| fmt.formatIntBuf(buf, x, 10, false, fmt.FormatOptions{}),
+            ET.SINT => |x| fmtstream.formatIntBuf(buf, x, 10, false, fmtstream.FormatOptions{}),
+            ET.UINT => |x| fmtstream.formatIntBuf(buf, x, 10, false, fmtstream.FormatOptions{}),
         };
     }
 };