Breaks `--trace` into two flags:
- `--parser_debug`, which sets the parser debug level (which I haven't dug into piping with `--trace`, but seemed likely to be troublesome)
- `--trace_file`, which now the type checker and interpreter will use for trace information (note compile errors should use a different channel)
Most of the file edits are just mechanical testdata flag updates: `sed -i 's/--trace/--parser_debug --trace_file=-/' testdata/**/*.carbon`
To explain the output paths:
- parse/compile errors: stderr
- print() calls: stdout
- parser tracing: `--parser_debug` option, stdout (formerly stdout if `--trace`)
- type check/compile tracing: `--trace_file=<file>`, giving `-` uses stdout (formerly stdout if `--trace`)
- return code of executed Carbon code: `--trace_file` if set, stdout if not (formerly stdout always)
I think lit_test accrued a bit of cruft as I switched approaches... I still may go further, but this is particularly fixing a bug where `FileCheck` (instead of `%{FileCheck}`) should've failed in tests.
I should emphasize that I am **completely cheating** here. This PR does not add support for actually _performing_ implicit conversions at run time, because the AST doesn't yet contain the necessary type information. At run time, code like `var p: Point = {.x = 1, .y = 2};` directly initializes the name `p` with the _struct_ value `{.x = 1, .y = 2}`; no object of type `Point` is actually created. I'm only getting away with this because we don't yet have any tests that can tell the difference.
Co-authored-by: Jon Meow <46229924+jonmeow@users.noreply.github.com>
Jon Meow
Jon Meow
Geoff RomerandJon Meow