reachableExprComptime

fn reachableExprComptime(
    gz: *GenZir,
    scope: *Scope,
    ri: ResultInfo,
    node: Ast.Node.Index,
    reachable_node: Ast.Node.Index,
    /// If `null`, the expression is not evaluated in a comptime context.
    comptime_reason: ?std.zig.SimpleComptimeReason,
) InnerError!Zir.Inst.Ref {
    const result_inst = if (comptime_reason) |r|
        try comptimeExpr(gz, scope, ri, node, r)
    else
        try expr(gz, scope, ri, node);

    if (gz.refIsNoReturn(result_inst)) {
        try gz.astgen.appendErrorNodeNotes(reachable_node, "unreachable code", .{}, &[_]u32{
            try gz.astgen.errNoteNode(node, "control flow is diverted here", .{}),
        });
    }
    return result_inst;
}