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People are currently seeing the current QDK one.

The following QASM code

OPENQASM 2.0;
qreg q[1];
U(θ,φ,λ) q[0];

is translated to this Q# code (not complete):

use q = Qubit[1] {
    Rx(θ, q[0]);
    Ry(φ, q[0]);
    Rz(λ, q[0]);
    ResetAll(q);
}

This logic is implemented in the following parts of Parser.cs:

However, the definition of QASM's U gate is:

And the above is not equal to Rz(λ)*Ry(φ)*Rx(θ).
See the following gist for more details:
https://gist.github.com/jond01/c942a7358e27e99aa6a68ea7ef42fe65

The correct translation is:
U(θ, φ, λ) = e^{i(φ+λ)/2}*Rz(φ)*Ry(θ)*Rz(λ)
(See Eqs. (1) and (2) in https://arxiv.org/pdf/2104.14722.pdf#page=11.)

It is essential to fix ParseUGate code and would be nice to implement a Q# operation U that contains the rotations and the global phase.