`hir::Ty` doesn't seem to know anything about type bounds and
`cx.tcx.type_of(def_id)` caused an ICE when it was passed a generic type
with a bound:
```
src/librustc_typeck/collect.rs:1311: unexpected non-type Node::GenericParam: Type { default: None, synthetic: None }
```
Converting it to a proper `Ty` fixes the ICE and catches a few more
places where the lint applies.
This does not save Clippy any time but it makes sure that the concurrent
build limit is not reached as quickly for the `rust-lang` Travis
account.
I can't create a permalink to the discussion somehow, so here's an
excerpt from the Infra channel:
```
[11:57 PM] pietroalbini: there is a clippy build (20 jobs) and a packed_simd one (42 builders) and a rustc one which isn't scheduling atm
[11:58 PM] pietroalbini: I don't think there is a way to prioritize rustc builds in the queue on travis, right?
[12:22 AM] alexcrichton: pietro: I don't think so no
[12:22 AM] alexcrichton: If it's a problem we should cull builds on other projects
[12:22 AM] alexcrichton: The rust repo is the #1 priority
```
Since the integration tests are rarely failing these days, I think it's
fine to not run them on every commit.
If needed, it's also still possible to do a `try` build with `@bors try`.
This checks if the value is a non-negative constant before linting about
losing the sign.
Because the `constant` function doesn't handle const functions, we check if
the value is from a call to a `max_value` function directly. A utility method
called `get_def_path` was added to make checking for the function paths
easier.
Fixes#2728
Add wildcard_match_arm lint
This lint prevents using a wildcard in a match arm. Implemented as a restriction currently, because this is pretty much an edge case. See #3649 for more information.
Didn't add any tests because I wasn't sure how, but if someone wants to point me in the right direction, I'd be happy to!
Add initial version of const_fn lint
This adds an initial version of a lint that can tell if a function could be `const`.
TODO:
- [x] Finish up the docs
- [x] Fix the ICE
cc #2440
