Add ERROR_FILE_EXISTS to ErrorKind conversion on Windows

[gkoz]

Bug report: https://users.rust-lang.org/t/detecting-error-kind-for-opening-file/6215
Reference: https://msdn.microsoft.com/en-us/library/windows/desktop/ms681382(v=vs.85).aspx#error_file_exists

[Stebalien]

How hard would it be to add a platform-independent test case for this (so it doesn't show up again)?

[gkoz]

Sorry, it's not obvious to me whether by 'this' you mean inaccurate ErrorKind::Other in general or something more specific.

[alexcrichton]

I believe what @Stebalien means is could we add a test for this? Ideally one that runs on both Unix and Windows and both situations give us AlreadyExists

[Stebalien]

I believe what @Stebalien means is could we add a test for this? Ideally one that runs on both Unix and Windows and both situations give us AlreadyExists

Ideally one that doesn't check for any specific platforms.

[gkoz]

Added a test.

[alexcrichton]

@bors: r+ 973ec7cfa9a14bc825102188e8ad40ff3d733cda

Thanks!

[bors]

⌛ Testing commit 973ec7c with merge ccd3352...

[bors]

💔 Test failed - auto-win-gnu-32-opt-rustbuild

[gkoz]

Apparently on Windows an this (creating a file when a directory exists) results in ErrorKind::PermissionDenied. Should I just not test this or make it conditional on !windows?

[alexcrichton]

It's fine to just omit this test if the PR is covered by the one above.

[gkoz]

Removed fancy test cases.

[alexcrichton]

@bors: r+

[bors]

📌 Commit 552afd3 has been approved by alexcrichton