The new builtin function result type inference doesn't consistently work inside array/vector initializer.

[IntegratedQuantum]

Zig Version

0.11.0-dev.3833+0a868dacd

Steps to Reproduce and Observed Behavior

fn takesAVector(vec: @Vector(1, f64)) void {
	_ = vec;
}
fn takesAnArray(arr: [1]f64) void {
	_ = arr;
}

pub fn main() void {
    var x: u64 = 0;
    var arr = [1]f64{@floatFromInt(x)}; // Works
    _ = arr;
    // _ = [1]f64{@floatFromInt(x)}; // Error
    // _ = takesAnArray([1]f64{@floatFromInt(x)}); // Error
    var vec = @Vector(1, f64){@floatFromInt(x)}; // Works
    _ = vec;
    // _ = @Vector(1, f64){@floatFromInt(x)}; // Error
    // _ = @Vector(1, f64){1} + @Vector(1, f64){@floatFromInt(x)}; // Error
    // _ = takesAVector(@Vector(1, f64){@floatFromInt(x)}); // Error
}

Uncommenting any of the above leads to the following error:

$ zig run test.zig
test.zig:5:17: error: @floatFromInt must have a known result type
     _ = [1]f64{@floatFromInt(x)}; // Error
                ^~~~~~~~~~~~~~~~

Expected Behavior

Given that the type is explicitly given in front of the initializer, the compiler should know what the field types are.

[mlugg]

Note that this is only an issue when the result is discarded (const y = [1]f64{@floatFromInt(x)} works fine).