Auto merge of #50275 - kennytm:rollup, r=kennytm

Rollup of 7 pull requests

Successful merges:

 - #49707 (Add "the Rustc book")
 - #50222 (Bump bootstrap compiler to 2018-04-24)
 - #50227 (Fix ICE with erroneous `impl Trait` in a trait impl)
 - #50229 (Add setting to go to item if there is only one result)
 - #50231 (Add more doc aliases)
 - #50246 (Make dump_{alloc,allocs,local}() no-ops when tracing is disabled.)
 - #49894 (Rename InternedString to LocalInternedString and introduce a new thread-safe InternedString)

Failed merges:

src/test/compile-fail/impl-trait/impl-generic-mismatch.rs

@@ -28,4 +28,15 @@ impl Bar for () {
     //~^ Error method `bar` has incompatible signature for trait
 }
 
+// With non-local trait (#49841):
+
+use std::hash::{Hash, Hasher};
+
+struct X;
+
+impl Hash for X {
+    fn hash(&self, hasher: &mut impl Hasher) {}
+    //~^ Error method `hash` has incompatible signature for trait
+}
+
 fn main() {}