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2864830941
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>
This directory contains the test cases.
Each test must have a filename of the form: t*.nim
Note: Testament is only aware of tests under a directory (eg tests/foo/) and will ignore
top-level tests like tests/tbar.nim.
Specs
Each test can contain a spec in a discard """ ... """ block.
Check out the parseSpec procedure in the specs module for a full and reliable reference
action
Specifies what action this test should take.
Default: run
Options:
compile- compiles the module and fails the test if compilations fails.run- compiles and runs the module, fails the test if compilation or execution of test code fails.reject- compiles the module and fails the test if compilation succeeds.
There are certain spec keys that imply run, including output and
outputsub.
Categories
Each folder under this directory represents a test category, which can be
tested by running koch tests pcat <category> (or cat to avoid parallel
testing, which is slower).
The folder dll contains simple DLL tests.
The folder realtimeGC contains a test for validating that the realtime GC
can run properly without linking against the nimrtl.dll/so.