Implement Chalk's debug methods using TLS

Chalk now panics if we don't implement these methods and run with CHALK_DEBUG,
so I thought I'd try to implement them 'properly'. Sadly, it seems impossible to
do without transmuting lifetimes somewhere. The problem is that we need a `&dyn
HirDatabase` to get names etc., which we can't just put into TLS. I thought I
could just use `scoped-tls`, but that doesn't support references to unsized
types. So I put the `&dyn` into another struct and put the reference to *that*
into the TLS, but I have to transmute the lifetime to 'static for that to work.

1 files changed, 7 insertions, 0 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 34f05e83a..20e7e745b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -995,6 +995,7 @@ dependencies = [
  "ra_prof",
  "ra_syntax",
  "rustc-hash",
+ "scoped-tls",
  "smallvec",
  "stdx",
  "test_utils",
@@ -1391,6 +1392,12 @@ dependencies = [
 ]
 
 [[package]]
+name = "scoped-tls"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ea6a9290e3c9cf0f18145ef7ffa62d68ee0bf5fcd651017e586dc7fd5da448c2"
+
+[[package]]
 name = "scopeguard"
 version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"