Comptime error return trace

[L zard]

Zig Version

0.14.0-dev.325+9356cb147

Steps to Reproduce and Observed Output

Given this function:

fn raiseError() !void {
    return error.Example;
}

With this comptime call:

pub fn main() void {
    comptime raiseError() catch @compileError("example error message");
}

error: example error message
example.zig:6:33: error: example error message

Exit code: -1

With this comptime call:

pub fn main() void {
    comptime raiseError() catch unreachable;
}

error: caught unexpected error 'Example'
example.zig:6:30: error: caught unexpected error 'Example'
example.zig:2:15: note: error returned here

Exit code: -1

Currently:

• catch @compileError reports an error message, but the error return trace is lost.
• catch unreachable displays the error return trace, but doesn't report an error message along.

Arguments against catch unreachable:

• It is meant be discouraged, so it shouldn't be the only way of having a comptime error's trace.
• @compileError asserts that the value is evaluated at comptime, unreachable doesn't.

Expected Output

@compileError should display the error return trace when called from an error catching block, the same way unreachable does, along its current behavior.