fixes#18125
Previously a tuple type like `(T, int)` would match an expected tuple
type `(U, int)` if `T` is a subtype of `U`. This is wrong since the
codegen does not handle type conversions of individual tuple elements in
a type conversion of an entire tuple. For this reason the compiler
already does not accept `(float, int)` for a matched type `(int, int)`,
however the code that checked for which relations are unacceptable
checked for `< isSubtype` rather than `<= isSubtype`, so subtypes were
not included in the unacceptable relations.
Update: Now only considered unacceptable when inheritance is used, as in
[`paramTypesMatch`](3379d26629/compiler/sigmatch.nim (L2252-L2254)).
Ideally subtype relations that don't need conversions, like `nil`,
`seq[empty]`, `range[0..5]` etc would be their own relation
`isConcreteSubtype` (which would also allow us to differentiate with
`openArray[T]`), but this is too big of a refactor for now.
To compensate for this making things like `let x: (Parent, int) =
(Child(), 0)` not compile (they would crash codegen before anyway but
should still work in principle), type inference for tuple constructors
is updated such that they call `fitNode` on the fields and their
expected types, so a type conversion is generated for the individual
subtype element.
(cherry picked from commit cfd69bad1a)
* round out tuple unpacking assignment, support underscores
fixes#18710
* fix test messages
* use discard instead of continue
Co-authored-by: Andreas Rumpf <rumpf_a@web.de>
---------
Co-authored-by: Andreas Rumpf <rumpf_a@web.de>
(cherry picked from commit 53d43e9671)
* fixes#22054; codegen for var tuples conv
* rethink fixes
* add test cases
* templates only
* fixes var tuples
* keep varness no matter what
* fixes typ.isNil
* make it work for generics
* restore isSubrange
* add a test case as requested
* tuple unpacking for vars as just sugar, allowing nesting
* set temp symbol AST
* hopeful fix some issues, add test for #19364
* always use temp for consts
* document, fix small issue
* fix manual indentation
* actually fix manual
* use helper proc
* don't resem temp tuple assignment
* Tuple unpacking now works for `for` vars
* Give error if length of tuple vars != length of tuple
* Fix error message showing wrong tuple length
* unpacking now works now for mutable items
* Update changelog
* removed from `compiler`:
* lists (deprecated 2 years ago)
* removed from `lib` (all deprecated 3 years ago):
* ssl
* matchers
* httpserver
* removed from `lib/deprecated`:
* unsigned
* actors (and three accompanying tests)
* parseurl
* moved to `lib/deprecated`:
* securehash (the reason for not directly removing - it was deprecated (only) one year ago)
