I can currently reproduce this with a new project on stable 1.23.0:
rustc 1.23.0 (766bd11c8 2018-01-01)
cargo 0.24.0 (45043115c 2017-12-05)

> cargo new --bin foo
> cd foo
> cargo build
> dir target\debug\*.pdb

No pdb will be found.

I believe this issue may be intermittent or environment-specific because I have seen it work in the past. Even in the past week I was doing several rounds of profiling which requires .pdb to be present and had no issues that I noticed.

The pdb is correctly generated in the target\debug\deps folder but not copied to the target\debug folder along with the .exe.

Also occurs with release targets with debug = true (which should be the default for windows-msvc, but that's another issue...)

Also occurs in nightly:
rustc 1.24.0-nightly (c8ddf2852 2017-12-07)
cargo 0.25.0-nightly (930f9d949 2017-12-05)

LINK.EXE is

Microsoft (R) Incremental Linker Version 14.12.25830.2
Copyright (C) Microsoft Corporation.  All rights reserved.

Not sure this is relevant as it's generating the .pdb, just not copying it into target.