Windows installer doesn't remove old installation

[cnd]

rts.rs:1:0: 1:0 error: multiple matching crates for `std`
rts.rs:1 fn main() {
         ^
note: candidates:
note: path: D:\Program Files\Rust\bin\rustc\i686-pc-mingw32\bin\std-6c65cf4b443341b1-0.7.dll
note: meta: name = "std"
note: meta: vers = "0.7"
note: meta: uuid = "c70c24a7-5551-4f73-8e37-380b11d80be8"
note: meta: url = "https://github.com/mozilla/rust/tree/master/src/libstd"
note: path: D:\Program Files\Rust\bin\rustc\i686-pc-mingw32\bin\std-6c65cf4b443341b1-0.8.dll
note: meta: name = "std"
note: meta: vers = "0.8"
note: meta: uuid = "c70c24a7-5551-4f73-8e37-380b11d80be8"
note: meta: url = "https://github.com/mozilla/rust/tree/master/src/libstd"

[huonw]

Triage: I can't test this at all.

cc @brson.

[brson]

Ew, this is bad. Nominating.

[pnkfelix]

Marking as 1.0 milestone, P-high.

[klutzy]

Same for nightly installers.

[BrianOtto]

I am running into this problem too. I use Windows 7 and had Rust 0.10 installed. I recently downloaded the latest Windows Installer so that I could take advantage of a recent bug fix, and it ended up installing the 0.11-pre libraries, without removing the older 0.10 ones. This has broken some previously working code with random numbers ...

test.rs:1:1: 1:19 error: multiple matching crates for `rand`
test.rs:1 extern crate rand;
          ^~~~~~~~~~~~~~~~~~
note: candidates:
note: path: C:\Rust\bin\rustlib\i686-pc-mingw32\lib\rand-dd29dab1-0.11-pre.dll
note: path: C:\Rust\bin\rustlib\i686-pc-mingw32\lib\librand-dd29dab1-0.11-pre.rlib
note: crate_id: rand#0.11-pre
note: path: C:\Rust\bin\rustlib\i686-pc-mingw32\lib\rand-15245696-0.10.dll
note: path: C:\Rust\bin\rustlib\i686-pc-mingw32\lib\librand-15245696-0.10.rlib
note: crate_id: rand#0.10

Deleting my Rust installation and re-installing fixes the problem, but it would be nice if I didn't have to do this every time I download the latest installer. Thanks!

[brson]

I've started on this. Should have a fix soon.