* Scan from line start when finding tag in tokenizer
This resolves a crash that can occur for invalid bytes like carriage
returns that are valid characters when not parsed from within literals.
There are potentially other edge cases this could resolve as well, as
the calling code for this function didn't account for any potential
'pending_invalid_tokens' that could be queued up by the tokenizer from
within another state.
* Fix carriage return crash in multiline string
Follow the guidance of #38:
> However CR directly before NL is interpreted as only a newline and not part of the multiline string. zig fmt will delete the CR.
Zig fmt already had code for deleting carriage returns, but would still
crash - now it no longer does so. Carriage returns encountered before
line-feeds are now appropriately removed on program compilation as well.
* Only accept carriage returns before line feeds
Previous commit was much less strict about this, this more closely
matches the desired spec of only allow CR characters in a CRLF pair, but
not otherwise.
* Fix CR being rejected when used as whitespace
Missed this comment from ziglang/zig-spec#83:
> CR used as whitespace, whether directly preceding NL or stray, is still unambiguously whitespace. It is accepted by the grammar and replaced by the canonical whitespace by zig fmt.
* Add tests for carriage return handling
This also makes another breaking change to for loops: in order to
capture a pointer of an element, one must take the address of array
values. This simplifies a lot of things, and makes more sense than how
it was before semantically.
It is still legal to use a for loop on an array value if the
corresponding element capture is byval instead of byref.
This strategy uses pointer arithmetic to iterate through the loop. This
has a problem, however, which is tuples. AstGen does not know whether a
given indexable is a tuple or can be iterated based on contiguous
memory. Tuples unlike other indexables cannot be represented as a
many-item pointer that is incremented as the loop counter.
So, after this commit, I will modify AstGen back closer to how @vexu had
it before, using a counter and array element access.
* Allow unbounded looping.
* Lower by incrementing raw pointers for each iterable rather than
incrementing a single index variable. This elides safety checks
without any analysis required thanks to the length assertion and
lowers to decent machine code even in debug builds.
- An "end" value is selected, prioritizing a counter if possible,
falling back to a runtime calculation of ptr+len on a slice input.
* Specialize on the pattern `0..`, avoiding an unnecessary subtraction
instruction being emitted.
* Add the `for_check_lens` ZIR instruction.
These operations are allowed because the string literals are just
pointers but they produce unexpected results. These errors prevent
beginners from shooting themselves in the foot while still allowing
advanced users to circumvent them if they desire to do so.
Closes#8290
PR #12837 handled control flow for break and return, but I forgot
about `continue`. This is effectively another break, so we just
need another `.restore_err_ret_index` ZIR instruction.
Resolves#13618.
All implicit casts can also potentially lead to a panic being emitted
but adding a dbg_stmt before every instruction is not feasible.
This adds 24k new instructions to the ZIR for Sema.zig increasing its
size from 3.8MiB to 4.0MiB.
Closes#13488
