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Diffstat (limited to 'src/library/scala/reflect/makro/Typers.scala')
| -rw-r--r-- | src/library/scala/reflect/makro/Typers.scala | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/src/library/scala/reflect/makro/Typers.scala b/src/library/scala/reflect/makro/Typers.scala new file mode 100644 index 0000000000..1ced2daccd --- /dev/null +++ b/src/library/scala/reflect/makro/Typers.scala @@ -0,0 +1,85 @@ +package scala.reflect.makro + +trait Typers { + self: Context => + + import mirror._ + + /** Contexts that represent macros in-flight, including the current one. Very much like a stack trace, but for macros only. + * Can be useful for interoperating with other macros and for imposing compiler-friendly limits on macro expansion. + * + * Is also priceless for emitting sane error messages for macros that are called by other macros on synthetic (i.e. position-less) trees. + * In that dire case navigate the ``openMacros'' stack, and it will most likely contain at least one macro with a position-ful macro application. + * See ``enclosingPosition'' for a default implementation of this logic. + * + * Unlike `enclosingMacros`, this is a def, which means that it gets recalculated on every invocation, + * so it might change depending on what is going on during macro expansion. + */ + def openMacros: List[Context] + + /** Types along with corresponding trees for which implicit arguments are currently searched. + * Can be useful to get information about an application with an implicit parameter that is materialized during current macro expansion. + * + * Unlike `enclosingImplicits`, this is a def, which means that it gets recalculated on every invocation, + * so it might change depending on what is going on during macro expansion. + */ + def openImplicits: List[(Type, Tree)] + + /** Typechecks the provided tree against the expected type ``pt'' in the macro callsite context. + * + * If ``silent'' is false, ``TypeError'' will be thrown in case of a typecheck error. + * If ``silent'' is true, the typecheck is silent and will return ``EmptyTree'' if an error occurs. + * Such errors don't vanish and can be inspected by turning on -Ymacro-debug. + * Unlike in ``inferImplicitValue'' and ``inferImplicitView'', ``silent'' is false by default. + * + * Typechecking can be steered with the following optional parameters: + * ``withImplicitViewsDisabled'' recursively prohibits implicit views (though, implicit vals will still be looked up and filled in), default value is false + * ``withMacrosDisabled'' recursively prohibits macro expansions and macro-based implicits, default value is false + */ + def typeCheck(tree: Tree, pt: Type = WildcardType, silent: Boolean = false, withImplicitViewsDisabled: Boolean = false, withMacrosDisabled: Boolean = false): Tree + + /** Infers an implicit value of the expected type ``pt'' in the macro callsite context. + * Optional ``pos'' parameter provides a position that will be associated with the implicit search. + * + * If ``silent'' is false, ``TypeError'' will be thrown in case of an inference error. + * If ``silent'' is true, the typecheck is silent and will return ``EmptyTree'' if an error occurs. + * Such errors don't vanish and can be inspected by turning on -Xlog-implicits. + * Unlike in ``typeCheck'', ``silent'' is true by default. + */ + def inferImplicitValue(pt: Type, silent: Boolean = true, withMacrosDisabled: Boolean = false, pos: Position = enclosingPosition): Tree + + /** Infers an implicit view from the provided tree ``tree'' from the type ``from'' to the type ``to'' in the macro callsite context. + * + * Optional ``pos'' parameter provides a position that will be associated with the implicit search. + * Another optional parameter, ``reportAmbiguous`` controls whether ambiguous implicit errors should be reported. + * If we search for a view simply to find out whether one type is coercible to another, it might be desirable to set this flag to ``false''. + * + * If ``silent'' is false, ``TypeError'' will be thrown in case of an inference error. + * If ``silent'' is true, the typecheck is silent and will return ``EmptyTree'' if an error occurs. + * Such errors don't vanish and can be inspected by turning on -Xlog-implicits. + * Unlike in ``typeCheck'', ``silent'' is true by default. + */ + def inferImplicitView(tree: Tree, from: Type, to: Type, silent: Boolean = true, withMacrosDisabled: Boolean = false, reportAmbiguous: Boolean = true, pos: Position = enclosingPosition): Tree + + /** Recursively resets symbols and types in a given tree. + * + * Note that this does not revert the tree to its pre-typer shape. + * For more info, read up https://issues.scala-lang.org/browse/SI-5464. + */ + def resetAllAttrs[T <: Tree](tree: T): T + + /** Recursively resets locally defined symbols and types in a given tree. + * + * Note that this does not revert the tree to its pre-typer shape. + * For more info, read up https://issues.scala-lang.org/browse/SI-5464. + */ + def resetLocalAttrs[T <: Tree](tree: T): T + + /** Represents an error during typechecking + */ + type TypeError <: Throwable + val TypeError: TypeErrorExtractor + abstract class TypeErrorExtractor { + def unapply(error: TypeError): Option[(Position, String)] + } +}
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