Use the trait-environment+type as the key. Note that these
are only invoked on types that live for the entire compilation
(no inference artifacts). We no longer need the various special-case
bits and caches that were in place before.
Instead of requesting the region maps for the entire crate, request for
a given item etc. Several bits of code were modified to take
`&RegionMaps` as input (e.g., the `resolve_regions_and_report_errors()`
function). I am not totally happy with this setup -- I *think* I'd
rather have the region maps be part of typeck tables -- but at least the
`RegionMaps` works in a "parallel" way to `FreeRegionMap`, so it's not
too bad. Given that I expect a lot of this code to go away with NLL, I
didn't want to invest *too* much energy tweaking it.
In master, this field was an arbitrary node-id (in fact, an id for
something that doesn't even exist in the HIR -- the `catch` node).
Breaks targeting this block used that id. In the newer system, this
field is a boolean, and any breaks targeted this block will use the
id of the block.
add `-C overflow-checks` option
In addition to defining and handling the new option, we also add a method on librustc::Session for determining the necessity of overflow checks. This method provides a single point to sort out the three (!) different ways for turning on overflow checks: -C debug-assertions, -C overflow-checks, and -Z force-overflow-checks.
I was seeing a [run-pass/issue-28950.rs](b1363a73ed/src/test/run-pass/issue-28950.rs) failure on my machine with these patches, but I was also seeing the failure without the changes to the core compiler. We'll see what travis says.
Fixes#33134. r? @alexcrichton
In addition to defining and handling the new option, we also add a
method on librustc::Session for determining the necessity of overflow
checks. This method provides a single point to sort out the three (!)
different ways for turning on overflow checks: -C debug-assertions, -C
overflow-checks, and -Z force-overflow-checks.
Fixes#33134.
This implements RFC 1624, tracking issue #37339.
- `FnCtxt` (in typeck) gets a stack of `LoopCtxt`s, which store the
currently deduced type of that loop, the desired type, and a list of
break expressions currently seen. `loop` loops get a fresh type
variable as their initial type (this logic is stolen from that for
arrays). `while` loops get `()`.
- `break {expr}` looks up the broken loop, and unifies the type of
`expr` with the type of the loop.
- `break` with no expr unifies the loop's type with `()`.
- When building MIR, `loop` loops no longer construct a `()` value at
termination of the loop; rather, the `break` expression assigns the
result of the loop. `while` loops are unchanged.
- `break` respects contexts in which expressions may not end with braced
blocks. That is, `while break { break-value } { while-body }` is
illegal; this preserves backwards compatibility.
- The RFC did not make it clear, but I chose to make `break ()` inside
of a `while` loop illegal, just in case we wanted to do anything with
that design space in the future.
This is my first time dealing with this part of rustc so I'm sure
there's plenty of problems to pick on here ^_^
Clean up `ast::Attribute`, `ast::CrateConfig`, and string interning
This PR
- removes `ast::Attribute_` (changing `Attribute` from `Spanned<Attribute_>` to a struct),
- moves a `MetaItem`'s name from the `MetaItemKind` variants to a field of `MetaItem`,
- avoids needlessly wrapping `ast::MetaItem` with `P`,
- moves string interning into `syntax::symbol` (`ast::Name` is a reexport of `symbol::Symbol` for now),
- replaces `InternedString` with `Symbol` in the AST, HIR, and various other places, and
- refactors `ast::CrateConfig` from a `Vec` to a `HashSet`.
r? @eddyb
