to get more reproducible output.

Fixes: rust-lang#32555

It's pretty confusing and this error triggers in resolve only when "shadowing" a
const, so let's make that clearer.

Adds documentation to Clone, specifying that Copy types should have a trivial Clone impl.

Fixes rust-lang#33416.

If the `-f` option isn't given, GNU tar will use environment variable
`TAPE` first, and next use the compiled-in default, which isn't
necessary `stdout` (it is the tape device `/dev/rst0` under OpenBSD for
example).

cc rust-lang#33417

…=jntrnr

degrade gracefully with empty spans

In rust-lang#32756, we solved the final test failure, but digging more into it the handling of that scenario could be better. The error was caused by an empty span supplied by the parser representing EOF. This patch checks that we cope more gracefully with such spans:

r? @jonathandturner

rustdoc: use btree map for where clauses

to get more reproducible output.

Fixes: rust-lang#32555

I've looked at the other uses of HashMap in rustdoc, and they seem ok to (i.e. they use `iter()` and related only for constructing a new map, or when the output goes into independent files).

Not sure what the cause of rust-lang#24473 is, it shouldn't be where clauses, but maybe it was also fixed inbetween since May 2015.

Cargo lock tidy check

A rebased PR for rust-lang#32901

… r=GuillaumeGomez

Improve diagnostics for constants being used in irrefutable patterns

It's pretty confusing and this error triggers in resolve only when "shadowing" a const, so let's make that clearer.

r? @steveklabnik

implement RFC 1521

Adds documentation to Clone, specifying that Copy types should have a trivial Clone impl.

Fixes rust-lang#33416.

I tried to use "should" and "must" as defined [here](https://tools.ietf.org/html/rfc2119).

cc @ubsan

make dist: specify the archive file as stdout

If the `-f` option isn't given, GNU tar will use environment variable
`TAPE` first, and next use the compiled-in default, which isn't
necessary `stdout` (it is the tape device `/dev/rst0` under OpenBSD for
example).

Implement RFC 1542

cc rust-lang#33417

r? @aturon