Description
I have found a significant time increase when I use "rustc --emit=metadata". I have located the source of such difference between two Nightlies, that I've named A and B, the time is for my code:
A:
rustup default nightly-2017-12-14
rustc 1.24.0-nightly (f8af59d95 2017-12-13)
commit-hash: f8af59d95225d122e38bb5dceb1027844d4ce170
host: x86_64-pc-windows-gnu
--emit=metadata time: 4.35 seconds
B:
rustup default nightly-2017-12-15
rustc 1.24.0-nightly (0077d128d 2017-12-14)
commit-hash: 0077d128d33543290140763ce7d84d05eb57c40a
host: x86_64-pc-windows-gnu
--emit=metadata time: 5.22 seconds
If you perform a complete compilation instead of just --emit=metadata the timing difference between the A and B compiler is of course much smaller. But --emit=metadata time is important to verify the code.
To show an example I've done:
cargo check --all
On rust-ndarray version 0.11.0, with both A and B. Then I've cleaned the directory:
rust-ndarray-master\target\debug\deps
And I've done "cargo check --all" again for both both A and B. This is not the best test for this problem, but it shows a difference (25.76 seconds for A, and 26.75 seconds for B), the difference percentage is small because it's not equivalent to just a "--emit=metadata".