This phase implements the following transformations:
-
For types of method and class parameters:
=> T becomes () ?=> T
-
For references to cbn-parameters:
x becomes x.apply()
-
For arguments to cbn parameters
e becomes () ?=> e
An optimization is applied: If the argument e to a cbn parameter is already
of type () ?=> T and is a pure expression, we avoid (2) and (3), i.e. we
pass e directly instead of () ?=> e.apply().
Note that () ?=> T cannot be written in source since user-defined context functions
must have at least one parameter. We use the type here as a convenient marker
of something that will erase to Function0, and where we know that it came from
a by-name parameter.
Note also that the transformation applies only to types of parameters, not to other
occurrences of ExprTypes. In particular, embedded occurrences in function types
such as (=> T) => U are left as-is here (they are eliminated in erasure).
Trying to convert these as well would mean traversing all the types, and that
leads to cyclic reference errors in many cases. This can cause problems in that
we might have sometimes a () ?=> T where a => T is expected. To compensate,
there is a new clause in TypeComparer#subArg that declares () ?=> T to be a
subtype of => T for arguments of type applications at any point after this phase
and up to erasure.
- Companion:
- object
Value members
Concrete methods
Can this transform change the parents of a class?
Can this transform change the parents of a class?
- Definition Classes
Denotations with a symbol where infoMayChange is false are guaranteed to be
unaffected by this transform, so transformInfo need not be run. This
can save time, and more importantly, can help avoid forcing symbol completers.
Denotations with a symbol where infoMayChange is false are guaranteed to be
unaffected by this transform, so transformInfo need not be run. This
can save time, and more importantly, can help avoid forcing symbol completers.
- Definition Classes
A name given to the Phase that can be used to debug the compiler. For
instance, it is possible to print trees after a given phase using:
A name given to the Phase that can be used to debug the compiler. For
instance, it is possible to print trees after a given phase using:
$ ./bin/scalac -Xprint:<phaseNameHere> sourceFile.scala
- Definition Classes
Inherited methods
Can this transform change the base types of a type?
Can this transform change the base types of a type?
- Inherited from:
- Phase
Can this transform create or delete non-private members?
Can this transform create or delete non-private members?
- Inherited from:
- Phase
Check what the phase achieves, to be called at any point after it is finished.
Check what the phase achieves, to be called at any point after it is finished.
- Inherited from:
- Phase
The sequence position of this phase in the given context where 0 is reserved for NoPhase and the first real phase is at position 1. -1 if the phase is not installed in the context.
The sequence position of this phase in the given context where 0 is reserved for NoPhase and the first real phase is at position 1. -1 if the phase is not installed in the context.
- Inherited from:
- Phase
Output should be checkable by TreeChecker
Output should be checkable by TreeChecker
- Inherited from:
- Phase
Is this phase the standard typerphase? True for TyperPhase, but not for other first phases (such as FromTasty or Parser). The predicate is tested in some places that perform checks and corrections. It's different from ctx.isAfterTyper (and cheaper to test).
Is this phase the standard typerphase? True for TyperPhase, but not for other first phases (such as FromTasty or Parser). The predicate is tested in some places that perform checks and corrections. It's different from ctx.isAfterTyper (and cheaper to test).
- Inherited from:
- Phase
The last phase during which the transformed denotations are valid
The last phase during which the transformed denotations are valid
- Inherited from:
- DenotTransformer
If set, use relaxed typing for all phases in group
If set, use relaxed typing for all phases in group
- Inherited from:
- MiniPhase
List of names of phases that should precede this phase
List of names of phases that should precede this phase
- Inherited from:
- Phase
Transform tree using all transforms of current group (including this one)
Transform tree using all transforms of current group (including this one)
- Inherited from:
- MiniPhase
Transform single node using all transforms following the current one in this group
Transform single node using all transforms following the current one in this group
- Inherited from:
- MiniPhase
Transform tree using all transforms following the current one in this group
Transform tree using all transforms following the current one in this group
- Inherited from:
- MiniPhase
The validity period of the transformed denotations in the given context
The validity period of the transformed denotations in the given context
- Inherited from:
- DenotTransformer