* late instantiation for the generic procs' default param values
* automatic mixin behaviour in concepts
Other fixes:
* don't render the automatically inserted default params in calls
* better rendering of tyFromExpr
This resulted in a codegen error in C++ mode, because the generic
types were not defined in modules where calls requiring downcasts
were used (generating a downcast forces the inclusion of the full
definition of the involved types).
This enables macros accepting arbitrary keyword arguments:
log("foo", prop1 = "bar", prop2 = "baz")
As an added bonus, simple templates with varargs arguments can now
forward their params to procs accepting keyword arguments.
This allows you to pass a template or a macro to another macro
which can then inspect the implementation of the former template/macro
using `getImpl`.
Since templates can be freely redefined, this allows you to treat
their symbols as compile-time variables that have lexical scope.
A motivating PoC example for a logging library taking advantage of
this will be provided in the next commit.
Implementation details:
* The name of a template or a macro will be consider a symbol if
the template/macro requires parameters
* For parameterless templates/macros, you can use `bindSym`, which
was extended to also work outside of compile-time procs.
* fix the usage of unresolved static[T] parameters in proc signatures
* fix tsametype and tmacrogenerics
* Allow creating composite type classes with concepts and using them in type signatures
* Allow integers to be used in ident concatenations
* Support using imported C++ generic types in proc signatures
* fixes#7230
* closes#7379
* re-enable some metatype tests
