012 registered variant beats the inline splice

// Pins that a REGISTERED variant wins over the inline splice.
//
// An effect-bearing event whose invocation sits at the top of a flow takes the
// INLINE LOWERING: the proc body is pasted into the caller as a labelled block
// rather than called. That lowering asked `findDefaultZigProc` for the body and
// nothing else, so a variant selected through `std/build:variants` was ignored
// and THE DEFAULT BODY RAN. Nothing failed — the wrong platform's code simply
// executed, and on a target where the default cannot compile it surfaced as a
// libc error naming a call the program does not make.
//
// The two bodies here differ in BOTH observable ways: the effect arm's argument
// and the terminal payload. So the test says which body ran, not merely that
// something ran.
//
// Sibling of 370_011, which pins the same selection through the handler-CALL
// path (its invocation is inside an impl, so it never reached the splice).

~import std/io
~import std/build

const std = @import("std");

~tor pump { n: i32 }
! tick i32
| done string

~proc pump|zig {
    tick(n);
    return .{ .done = "default" };
}

~proc pump|alt {
    tick(n * 2);
    return .{ .done = "alt" };
}

~std/build:variants {
    "input:pump": "alt"
}
| configured _ |> _
| skipped _ |> _
| invalid-event _ |> _

~tor show { value: i32 }

~proc show|zig {
    std.debug.print("{}\n", .{value});
}

~pump(n: 21)
! tick t |> show(value: t)
| done d |> std/io:print.ln(d)