Easiest to reproduce with the WASI test patches:
$ zig test wasi.zig -target wasm32-wasi --test-cmd wasmtime --test-cmd-bin
const std = @import("std");
test "safe" {
var buf: [64000]u8 = undefined;
std.debug.warn("{*}\n", &buf);
}
test "broken in debug" {
var buf: [65000]u8 = undefined;
std.debug.warn("{*}\n", &buf);
}
test "broken in release-safe" {
var buf: [66000]u8 = undefined;
std.debug.warn("{*}\n", &buf);
}
test "broken in release-fast" {
var buf: [68000]u8 = undefined;
std.debug.warn("{*}\n", &buf);
}