Also, get rid of two FIXMEs by refactoring some code, and moving the
call_expr check for be expressions into typeck, where it seems to
make more sense.

And suggest changing them to loop { ... }. Had to fix the few
remaining while true loops (in core::io). Closes #1962.

As per Issue #1193. Closes #1193.

I had to rename a few variables ("info" and "epsilon") to avoid
clashing with in-scope constants, which is responsible for all the
changes other than resolve and issue-1193.rs.

As per a FIXME in syntax::parse::classify, move predicates on exprs
and stmts into classify, out of pprust

Eta-reduce a function, fold over ty constrs, and annotate a FIXME.

Inline some one-off functions, add an error message, annotate a FIXME

I removed a FIXME about cleaning up function names because I
couldn't tell what needed cleaning up. If you know, please add a
FIXME and a corresponding issue tracker issue that explains the
problem!

simple update of keywords.txt

The runtime is in an uncertain state here and, instead of thinking
about how to make the logger work correctly, let's just avoid it.

Currently, it ends up hitting an assert saying that we can't log on
the rust stack.

Closes #2222

Closes #1892

Closes #2053

Closes #2141

Closes #2177

Closes #2055

Closes #2142