FixedBufferStream needs to declare Error in order to be wrapped with other Readers

[yarrumretep]

Zig Version

0.13.0

Steps to Reproduce and Observed Behavior

Still getting my bearings, but I believe this warrants a bug report. The FixedBufferStream module declares various error unions, but doesn't declare one called Error which is required to use it with wrapping Readers and Writers such as BufferedReader/Writer or CountingReader.

For instance, this code fails to compile:

test "counting reader" {
    const buffer = "hello world";
    const reader = std.io.fixedBufferStream(buffer[0..]);
    const counter = std.io.countingReader(reader);
    const read_buffer: [5]u8 = undefined;
    const n = try counter.read(read_buffer);
    try std.testing.expectEqual(n, 5);
}

The error message is

opt/homebrew/Cellar/zig/0.13.0/lib/zig/std/io/counting_reader.zig:11:37: error: struct 'io.fixed_buffer_stream.FixedBufferStream([]const u8)' has no member named 'Error'
opt/homebrew/Cellar/zig/0.13.0/lib/zig/std/io/fixed_buffer_stream.zig:10:12: note: struct declared here

This issue comes up when creating tests where you want to feed static data into a nested Reader/Writer.

Expected Behavior

Ideally, FixedBufferStream would generate an Error union that is dependent on it's ability to generate a writer (based on the const-ness of the buffer) - that seems to be the only case where it generates an error. The other error unions are currently empty.

[yarrumretep]

OK - this may be a mis-fire on my part. I guess one should call reader() on these readers to get them wrapped with the GenericReader. If that's the designed behavior then please go ahead and close this.