The error handling in libsyntax changed to use a `DiagnosticBuilder`
type in the `Err` variant of `PResult`. This type has `emit()` and
`cancel()` methods. Once created, errors must be emitted or canceled; if
not, the `Drop` impl on `DiagnosticBuilder` will panic.
The first syntex_syntax release to include this change was v0.25.0. The
bump from v0.23.0 to v0.29.1 in #847 did not add any `cancel()` calls,
even though at least one was required. There may be others not caught in
this commit.
This commit adds a CodeMapSpanUtils extension trait on CodeMap, and
moves some functions to methods there:
- span_after
- span_after_last
- span_before
This better reflects them being lookup methods on the codemap.
The problem is essentially that if we try to parse a token tree using a
CodeMap different from the one the tree was originally parsed with,
spans become nonsense. Since CodeMaps can't be cloned, we're basically
forced to use the original ParseSess for additional parsing.
Ideally, rustfmt would be a bit more clever and figure out how to parse
macro arguments based on the definition of the macro itself, rather than
just guessing that a particular token sequence looks like an expression,
but this is good enough for now.
Fixes#538.
This removes usage of:
* PathExt
* split_last
* split_last_mut
* catch_panic
The catch_panic one was a little tricky as the ident interner needed to be
cloned across threads (a little unsafely), but it should otherwise be good to
go.
