This handles namespacing of functions. Parsing and semantics are changed
significantly, while lowering works without changes. Variables can't be
namespaced yet because they're dealing with patterns, and I didn't dig
through that code.
Most of the logic is done through the new name declaration stack, which
is necessary because semantics isn't quite sure where the declaration
name ends. It'd be complex for parsing to send a signal about this,
probably involving node variants and rewrites of the tree, and this
solution seems to work well. Unfortunately this means a new stack, but
that may be inevitable due to the extra information needing to be
tracked.
Note this doesn't deal with scoped lookups of non-namespace things,
which we'll need for generics. That'll probably involve pushing resolved
scopes onto a stack (or maybe just setting a singleton value?) to affect
contextual name lookup. But, I think the basics are there to make it
work when we can test the behavior.
This renames "designator expression" to "qualified expression" and adds
"qualified declaration" in order to use terminology more consistent with
C++.
Namespaces will probably need to be considered for name mangling down
the line, but this still uses the basic name.
This PR renames parse nodes on a Name/NameExpression taxonomy. NameExpressions occur in a name context. The difference is that in non-expression contexts it's useful to return the identifier / string ID for adding to name lookup, whereas in expression contexts it's useful to return the resolved node ID for consistency with other expressions.
In the code, I do note SelfValueName is returned in the expression context: I'd expect this to change, as `self` in `[self: Self]` versus `self.Foo()` will probably be best handled similarly to the above. That means that, in the proposed taxonomy, both `SelfValueName` and `SelfValueNameExpression` will exist in order to assist semantics.
To contrast choices:
Original | Current | [zygoloid suggestion](https://discord.com/channels/655572317891461132/655578254970716160/1121581663399464970) | [This PR](https://discord.com/channels/655572317891461132/655578254970716160/1121814551789318215)
--- | --- | --- | ---
DeclaredName/DesignatedName | Identifier | NameComponent | Name
NameReference | NameReference | NameReference | NameExpression
SelfValueIdentifier | SelfValueIdentifier | SelfValueReference | SelfValueName
SelfTypeIdentifier | SelfTypeIdentiifer | SelfTypeReference | SelfTypeNameExpression
This is just a simplification: I think these different forms are getting in the way more than they're helping, particularly as I was looking into namespace functionality. The handling in semantics can be identical, providing a more uniform behavior.
The intent of this change is that instead of paths looking like `explorer/testdata/foo/bar.carbon` (repo-relative), they're now just `bar.carbon` (local). The consequence is that paths should be a bit more durable in various environments, and just paths should be shorter and easier to read.
The explorer's prelude is an exception to this since it comes from data, rather than being the test target. Due to the change in approaches, it needs the regex again.
Uses #2829
This builds on #2814 by adding the test framework to the toolchain. On Linux, this is 7s -> 4s for me. #2811 has more detailed timing for the explorer, which also had more dramatic changes because it's about 3x more tests run in 2x as many ways (6x total).
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
I think it'd be helpful to examine what the parse tree looks like in failure cases.
Note, I'm not sure that the behavior of the recovery situations is correct; the test had been asserting that the parse tree should indicate it's error free. However, this means that the only signal the the driver that the input is invalid is that the diagnostic emitter was used. I think it may be important to have it return a non-zero error to prevent compile, or we can turn these into warnings but then "requiring a space" is wrong.
Either way, that's a concern I have with the pre-existing recovery behavior: I'm just trying to highlight it as I make this change, because now the test is really that nodes aren't tagged with has_error.
Jon Ross-Perkins
