value with comptime-only type '@TypeOf(null)' depends on runtime control flow

[ehaas]

Zig Version

0.12.0-dev.47+0461a64a9

Steps to Reproduce and Observed Behavior

fn foo(x: bool) error{OutOfMemory}![]const u8 {
    if (x) return "" else return error.OutOfMemory;
}

test {
    var x = true;
    const val = foo(x) catch |err| switch (err) {
        error.OutOfMemory => null,
    };
    _ = val;
}

~ % zig test test.zig
test.zig:7:36: error: value with comptime-only type '@TypeOf(null)' depends on runtime control flow
    const val = foo(x) catch |err| switch (err) {
                                   ^~~~~~
test.zig:7:24: note: runtime control flow here
    const val = foo(x) catch |err| switch (err) {
                ~~~~~~~^~~~~

Giving val an explicit type of ?[]const u8 prevents the error

Expected Behavior

Test passes

[mlugg]

Will be solved by the implementation of #11957

[andrewrk]

fixed by acca16c