This rewrite improves some error messages, hugely simplifies the logic,
and fixes several bugs. One of these bugs is technically a new rule
which Andrew and I agreed on: if a parameter has a comptime-only type
but is not declared `comptime`, then the corresponding call argument
should not be *evaluated* at comptime; only resolved. Implementing this
required changing how function types work a little, which in turn
required allowing a new kind of function coercion for some generic use
cases: function coercions are now allowed to implicitly *remove*
`comptime` annotations from parameters with comptime-only types. This is
okay because removing the annotation affects only the call site.
Resolves: #22262
This commit reworks how anonymous struct literals and tuples work.
Previously, an untyped anonymous struct literal
(e.g. `const x = .{ .a = 123 }`) was given an "anonymous struct type",
which is a special kind of struct which coerces using structural
equivalence. This mechanism was a holdover from before we used
RLS / result types as the primary mechanism of type inference. This
commit changes the language so that the type assigned here is a "normal"
struct type. It uses a form of equivalence based on the AST node and the
type's structure, much like a reified (`@Type`) type.
Additionally, tuples have been simplified. The distinction between
"simple" and "complex" tuple types is eliminated. All tuples, even those
explicitly declared using `struct { ... }` syntax, use structural
equivalence, and do not undergo staged type resolution. Tuples are very
restricted: they cannot have non-`auto` layouts, cannot have aligned
fields, and cannot have default values with the exception of `comptime`
fields. Tuples currently do not have optimized layout, but this can be
changed in the future.
This change simplifies the language, and fixes some problematic
coercions through pointers which led to unintuitive behavior.
Resolves: #16865
The compiler actually doesn't need any functional changes for this: Sema
does reification based on the tag indices of `std.builtin.Type` already!
So, no zig1.wasm update is necessary.
This change is necessary to disallow name clashes between fields and
decls on a type, which is a prerequisite of #9938.
This does not completely ignore static asserts - they are validated by aro
during parsing; any failures will render an error and non-zero exit code.
Emit a warning comment that _Static_asserts are not translated - this
matches the behavior of the existing clang-based translate-c.
Aro currently does not store source locations for _Static_assert
declarations so I've hard-coded token index 0 for now.
Part of #19063.
Primarily, this moves Aro from deps/ to lib/compiler/ so that it can be
lazily compiled from source. src/aro_translate_c.zig is moved to
lib/compiler/aro_translate_c.zig and some of Zig CLI logic moved to a
main() function there.
aro_translate_c.zig becomes the "common" import for clang-based
translate-c.
Not all of the compiler was able to be detangled from Aro, however, so
it still, for now, remains being compiled with the main compiler
sources due to the clang-based translate-c depending on it. Once
aro-based translate-c achieves feature parity with the clang-based
translate-c implementation, the clang-based one can be removed from Zig.
Aro made it unnecessarily difficult to depend on with these .def files
and all these Zig module requirements. I looked at the .def files and
made these observations:
- The canonical source is llvm .def files.
- Therefore there is an update process to sync with llvm that involves
regenerating the .def files in Aro.
- Therefore you might as well just regenerate the .zig files directly
and check those into Aro.
- Also with a small amount of tinkering, the file size on disk of these
generated .zig files can be made many times smaller, without
compromising type safety in the usage of the data.
This would make things much easier on Zig as downstream project,
particularly we could remove those pesky stubs when bootstrapping.
I have gone ahead with these changes since they unblock me and I will
have a chat with Vexu to see what he thinks.
