todo: We can also give a deprecation message for `ltPtr`/`lePtr`
matching for cstring in `magicsAfterOverloadResolution`
follow up https://github.com/nim-lang/Nim/pull/24942
(cherry picked from commit ade500b2cb)
fixes#23114
As in https://github.com/nim-lang/Nim/pull/22074, expressions in
bracketed emit are strictly typechecked, this PR applies the same check
for symbols in asm statements in order to keep them consistent.
(cherry picked from commit 3c4246dd24)
closes https://github.com/nim-lang/RFCs/issues/380, fixes#4773, fixes
#14729, fixes#16755, fixes#18150, fixes#22984, refs #11167 (only some
comments fixed), refs #12620 (needs tiny workaround)
The compiler gains a concept of root "nominal" types (i.e. objects,
enums, distincts, direct `Foo = ref object`s, generic versions of all of
these). Exported top-level routines in the same module as the nominal
types that their parameter types derive from (i.e. with
`var`/`sink`/`typedesc`/generic constraints) are considered attached to
the respective type, as the RFC states. This happens for every argument
regardless of placement.
When a call is overloaded and overload matching starts, for all
arguments in the call that already have a type, we add any operation
with the same name in the scope of the root nominal type of each
argument (if it exists) to the overload match. This also happens as
arguments gradually get typed after every overload match. This restricts
the considered overloads to ones attached to the given arguments, as
well as preventing `untyped` arguments from being forcefully typed due
to unrelated overloads. There are some caveats:
* If no overloads with a name are in scope, type bound ops are not
triggered, i.e. if `foo` is not declared, `foo(x)` will not consider a
type bound op for `x`.
* If overloads in scope do not have enough parameters up to the argument
which needs its type bound op considered, then type bound ops are also
not added. For example, if only `foo()` is in scope, `foo(x)` will not
consider a type bound op for `x`.
In the cases of "generic interfaces" like `hash`, `$`, `items` etc. this
is not really a problem since any code using it will have at least one
typed overload imported. For arbitrary versions of these though, as in
the test case for #12620, a workaround is to declare a temporary
"template" overload that never matches:
```nim
# neither have to be exported, just needed for any use of `foo`:
type Placeholder = object
proc foo(_: Placeholder) = discard
```
I don't know what a "proper" version of this could be, maybe something
to do with the new concepts.
Possible directions:
A limitation with the proposal is that parameters like `a: ref Foo` are
not attached to any type, even if `Foo` is nominal. Fixing this for just
`ptr`/`ref` would be a special case, parameters like `seq[Foo]` would
still not be attached to `Foo`. We could also skip any *structural* type
but this could produce more than one nominal type, i.e. `(Foo, Bar)`
(not that this is hard to implement, it just might be unexpected).
Converters do not use type bound ops, they still need to be in scope to
implicitly convert. But maybe they could also participate in the nominal
type consideration: if `Generic[T] = distinct T` has a converter to `T`,
both `Generic` and `T` can be considered as nominal roots.
The other restriction in the proposal, being in the same scope as the
nominal type, could maybe be worked around by explicitly attaching to
the type, i.e.: `proc foo(x: T) {.attach: T.}`, similar to class
extensions in newer OOP languages. The given type `T` needs to be
obtainable from the type of the given argument `x` however, i.e.
something like `proc foo(x: ref T) {.attach: T.}` doesn't work to fix
the `ref` issue since the compiler never obtains `T` from a given `ref
T` argument. Edit: Since the module is queried now, this is likely not
possible.
---------
Co-authored-by: Andreas Rumpf <rumpf_a@web.de>
(cherry picked from commit 2864830941)
fixes#16376
The way the compiler handled generic proc instantiations in calls (like
`foo[int](...)`) up to this point was to instantiate `foo[int]`, create
a symbol for the instantiated proc (or a symchoice for multiple procs
excluding ones with mismatching generic param counts), then perform
overload resolution on this symbol/symchoice. The exception to this was
when the called symbol was already a symchoice node, in which case it
wasn't instantiated and overloading was called directly ([these
lines](b7b1313d21/compiler/semexprs.nim (L3366-L3371))).
This has several problems:
* Templates and macros can't create instantiated symbols, so they
couldn't participate in overloaded explicit generic instantiations,
causing the issue #16376.
* Every single proc that can be instantiated with the given generic
params is fully instantiated including the body. #9997 is about this but
isn't fixed here since the instantiation isn't in a call.
The way overload resolution handles explicit instantiations by itself is
also buggy:
* It doesn't check constraints.
* It allows only partially providing the generic parameters, which makes
sense for implicit generics, but can cause ambiguity in overloading.
Here is how this PR deals with these problems:
* Overload resolution now always handles explicit generic instantiations
in calls, in `initCandidate`, as long as the symbol resolves to a
routine symbol.
* Overload resolution now checks the generic params for constraints and
correct parameter count (ignoring implicit params). If these don't
match, the entire overload is considered as not matching and not
instantiated.
* Special error messages are added for mismatching/missing/extra generic
params. This is almost all of the diff in `semcall`.
* Procs with matching generic parameters now instantiate only the type
of the signature in overload resolution, not the proc itself, which also
works for templates and macros.
Unfortunately we can't entirely remove instantiations because overload
resolution can't handle some cases with uninstantiated types even though
it's resolved in the binding (see the last 2 blocks in
`texplicitgenerics`). There are also some instantiation issues with
default params that #24005 didn't fix but I didn't want this to become
the 3rd huge generics PR in a row so I didn't dive too deep into trying
to fix them. There is still a minor instantiation fix in `semtypinst`
though for subscripts in calls.
Additional changes:
* Overloading of `[]` wasn't documented properly, it somewhat is now
because we need to mention the limitation that it can't be done for
generic procs/types.
* Tests can now enable the new type mismatch errors with just
`-d:testsConciseTypeMismatch` in the command.
Package PRs:
- using fork for now:
[combparser](https://github.com/PMunch/combparser/pull/7) (partial
generic instantiation)
- merged: [cligen](https://github.com/c-blake/cligen/pull/233) (partial
generic instantiation but non-overloaded + template)
- merged: [neo](https://github.com/andreaferretti/neo/pull/56) (trying
to instantiate template with no generic param)
fixes#15314, fixes#24002
The OpenSym behavior first added to generics in #23091 now also applies
to templates, since templates can also capture symbols that are meant to
be replaced by local symbols if the context imports symbols with the
same name, as in the issue #24002. The experimental switch
`templateOpenSym` is added to enable this behavior for templates only,
and the experimental switch `openSym` is added to enable it for both
templates and generics, and the documentation now mainly mentions this
switch.
Additionally the logic for `nkOpenSymChoice` nodes that were previously
wrapped in `nkOpenSym` now apply to all `nkOpenSymChoice` nodes, and so
these nodes aren't wrapped in `nkOpenSym` anymore. This means
`nkOpenSym` can only have children of kind `nkSym` again, so it is more
in line with the structure of symchoice nodes. As for why they aren't
merged with `nkOpenSymChoice` nodes yet, we need some way to signal that
the node shouldn't become ambiguous if other options exist at
instantiation time, we already captured a symbol at the beginning and
another symbol can only replace it if it's closer in scope and
unambiguous.
fixes#23865
The node flag `nfOpenSym` implemented in #23091 for sym nodes is now
also implemented for open symchoices. This means the intended behavior
is still achieved when multiple overloads are in scope to be captured,
so the issue is fixed. The code for the flag is documented and moved
into a helper proc and the experimental switch is now enabled for the
compiler test suite.
**TODO**
- [x] fixes changelog
With the new option `nimPreviewVtables`, `methods` are confined in the
same module where the type of the first parameter is defined
- [x] make it opt in after CI checks its feasibility
## In the following-up PRs
- [ ] in the following PRs, refactor code into a more efficient one
- [ ] cpp needs special treatments since it cannot embed array in light
of the preceding limits: ref
https://github.com/nim-lang/Nim/pull/20977#discussion_r1035528927; we
can support cpp backends with vtable implementations later on the
comprise that uses indirect vtable access
---------
Co-authored-by: Andreas Rumpf <rumpf_a@web.de>
fixes#22286
ref https://forum.nim-lang.org/t/10642
For backwards compatibilities, we might need to keep the changes under a
preview compiler flag. Let's see how many packags it break.
**TODO** in the following PRs
- [ ] Turn the `var T` destructors warning into an error with
`nimPreviewNonVarDestructor`
---------
Co-authored-by: Andreas Rumpf <rumpf_a@web.de>
* clean up some test categories
* mention exact slice issue
* magics into system
* move trangechecks into overflow
* move tmemory to system
* try fix CI
* try fix CI
* final CI fix
* unnamed break in the block now gives an error
* bootstrap
* fixes
* more fixes
* break with label
* label again
* one moee
* Delete test5.txt
* it now gives a UnnamedBreak warning
* change the URL of bump back to the original one
* silence error output from template_various.nim
* any => auto in tests
* avoid showing failed for parseSpec since this is expected behavior in 2 cases: tincludefile.nim, tnav1.nim
* enforce InheritFromException
* fixup
* compiler/vmhooks: add getVar to allow vmops with var params
* addFloat vmops with var param
* cgen now renders float32 literals in c backend using roundtrip float to string
