scala.reflect.macros.blackbox

# Context

###
Related Doc: package blackbox

#### trait Context extends Aliases with Enclosures with Names with Reifiers with FrontEnds with Infrastructure with Typers with Parsers with Evals with ExprUtils with Internals

EXPERIMENTAL

The blackbox Scala macros context.

See the overview page for a description of how macros work. This documentation entry provides information on the API available to macro writers.

A macro context wraps a compiler universe exposed in `universe` and having type scala.reflect.macros.Universe. This type is a refinement over the generic reflection API provided in scala.reflect.api.Universe. The extended Universe provides mutability for reflection artifacts (e.g. macros can change types of compiler trees, add annotation to symbols representing definitions, etc) and exposes some internal compiler functionality such as `Symbol.deSkolemize` or `Tree.attachments`.

Another fundamental part of a macro context is `macroApplication`, which provides access to the tree undergoing macro expansion. Parts of this tree can be found in arguments of the corresponding macro implementations and in `prefix`, but `macroApplication` gives the full picture.

Other than that, macro contexts provide facilities for typechecking, exploring the compiler's symbol table and enclosing trees and compilation units, evaluating trees, logging warnings/errors and much more. Refer to the documentation of top-level traits in this package to learn the details.

If a macro def refers to a macro impl that uses `blackbox.Context`, then this macro def becomes a blackbox macro, which means that its expansion will be upcast to its return type, enforcing faithfullness of that macro to its type signature. Whitebox macros, i.e. the ones defined with `whitebox.Context`, aren't bound by this restriction, which enables a number of important use cases, but they are also going to enjoy less support than blackbox macros, so choose wisely. See the Macros Guide for more information.

Source
  Context.scala
See also

  `scala.reflect.macros.whitebox.Context`

Linear Supertypes
Internals, ExprUtils, Evals, Parsers, Typers, Infrastructure, FrontEnds, Reifiers, Names, Enclosures, Aliases, AnyRef, Any
Known Subclasses
Context
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Inherited

1. Context
2. Internals
3. ExprUtils
4. Evals
5. Parsers
6. Typers
7. Infrastructure
8. FrontEnds
9. Reifiers
10. Names
11. Enclosures
12. Aliases
13. AnyRef
14. Any

Implicitly

1. by any2stringadd
2. by StringFormat
3. by Ensuring
4. by ArrowAssoc

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Visibility

1. Public
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### Type Members

1. #### trait ContextInternalApi extends MacroInternalApi

   Definition Classes
     Internals
   See also

     scala.reflect.api.Internals

2. #### type Expr[+T] = Universe.Expr[T]

   Expr wraps an abstract syntax tree and tags it with its type.

   Expr wraps an abstract syntax tree and tags it with its type.

   Definition Classes
     Aliases

3. #### type Modifiers = Universe.Modifiers

   The type of tree modifiers.

   The type of tree modifiers.

   Definition Classes
     Aliases

4. #### type Name = Universe.Name

   The abstract type of names.

   The abstract type of names.

   Definition Classes
     Aliases

5. #### type Position = Universe.Position

   Defines a universe-specific notion of positions.

   Defines a universe-specific notion of positions.

   Definition Classes
     Aliases

6. #### abstract type PrefixType

   The type of the prefix tree from which the macro is selected.

   The type of the prefix tree from which the macro is selected. See the documentation entry for `prefix` for an example.

7. #### type Scope = Universe.Scope

   The base type of all scopes.

   The base type of all scopes.

   Definition Classes
     Aliases

8. #### type Symbol = Universe.Symbol

   The type of symbols representing declarations.

   The type of symbols representing declarations.

   Definition Classes
     Aliases

9. #### type TermName = Universe.TermName

   The abstract type of names representing terms.

   The abstract type of names representing terms.

   Definition Classes
     Aliases

10. #### type Tree = Universe.Tree

    The type of Scala abstract syntax trees.

    The type of Scala abstract syntax trees.

    Definition Classes
      Aliases

11. #### type Type = Universe.Type

    The type of Scala types, and also Scala type signatures.

    The type of Scala types, and also Scala type signatures. (No difference is internally made between the two).

    Definition Classes
      Aliases

12. #### type TypeName = Universe.TypeName

    The abstract type of names representing types.

    The abstract type of names representing types.

    Definition Classes
      Aliases

13. #### type TypeTag[T] = Universe.TypeTag[T]

    The type of type tags.

    The type of type tags.

    Definition Classes
      Aliases

14. #### type TypecheckException = macros.TypecheckException

    Definition Classes
      Typers
    See also

      `scala.reflect.macros.TypecheckException`

15. #### abstract type TypecheckMode

    Represents mode of operations of the typechecker underlying `c.typecheck` calls.

    Represents mode of operations of the typechecker underlying `c.typecheck` calls. Is necessary since the shape of the typechecked tree alone is not enough to guess how it should be typechecked. Can be EXPRmode (typecheck as a term), TYPEmode (typecheck as a type) or PATTERNmode (typecheck as a pattern).

    Definition Classes
      Typers

16. #### type WeakTypeTag[T] = Universe.WeakTypeTag[T]

    The type of weak type tags.

    The type of weak type tags.

    Definition Classes
      Aliases

17. #### type CompilationUnit = Universe.CompilationUnit

    The type of compilation units.

    The type of compilation units.

    Definition Classes
      Aliases
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) c.enclosingTree-style APIs are now deprecated; consult the scaladoc for more information

    See also

      scala.reflect.macros.Enclosures

18. #### case class EnclosureException(expected: Class[_], enclosingTrees: List[blackbox.Context.Tree]) extends Exception with Product with Serializable

    Indicates than one of the enclosure methods failed to find a tree of required type among enclosing trees.

    Indicates than one of the enclosure methods failed to find a tree of required type among enclosing trees.

    Definition Classes
      Enclosures
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) c.enclosingTree-style APIs are now deprecated; consult the scaladoc for more information

    See also

      scala.reflect.macros.Enclosures

19. #### type Run = Universe.Run

    The type of compilation runs.

    The type of compilation runs.

    Definition Classes
      Aliases
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) c.enclosingTree-style APIs are now deprecated; consult the scaladoc for more information

    See also

      scala.reflect.macros.Enclosures

### Abstract Value Members

1. #### abstract def Expr[T](tree: Tree)(implicit arg0: WeakTypeTag[T]): Expr[T]

   A shorthand to create an expr.

   A shorthand to create an expr.

   Unlike the conventional expr factory, which requires a scala.reflect.api.TreeCreator, this one accepts a regular tree, but the resulting exprs are unable of being migrated to other universes/mirrors (the functionality normally not needed for macros, since there is only one compile-time universe and only one compile-time mirror).

   Definition Classes
     Aliases

2. #### abstract val PATTERNmode: TypecheckMode

   Indicates that an argument to `c.typecheck` should be typechecked as a pattern.

   Indicates that an argument to `c.typecheck` should be typechecked as a pattern.

   Definition Classes
     Typers

3. #### abstract val TERMmode: TypecheckMode

   Indicates that an argument to `c.typecheck` should be typechecked as a term.

   Indicates that an argument to `c.typecheck` should be typechecked as a term. This is the default typechecking mode in Scala 2.11 and the only one supported in Scala 2.10.

   Definition Classes
     Typers

4. #### abstract val TYPEmode: TypecheckMode

   Indicates that an argument to `c.typecheck` should be typechecked as a type.

   Indicates that an argument to `c.typecheck` should be typechecked as a type.

   Definition Classes
     Typers

5. #### abstract def TypeTag[T](tpe: Type): TypeTag[T]

   A shorthand to create a type tag.

   A shorthand to create a type tag.

   Unlike the conventional type tag factory, which requires a scala.reflect.api.TypeCreator, this one accepts a regular type, but the resulting type tags are unable of being migrated to other universes/mirrors (the functionality normally not needed for macros, since there is only one compile-time universe and only one compile-time mirror).

   Definition Classes
     Aliases

6. #### abstract def WeakTypeTag[T](tpe: Type): WeakTypeTag[T]

   A shorthand to create a weak type tag.

   A shorthand to create a weak type tag.

   Unlike the conventional type tag factory, which requires a scala.reflect.api.TypeCreator, this one accepts a regular type, but the resulting type tags are unable of being migrated to other universes/mirrors (the functionality normally not needed for macros, since there is only one compile-time universe and only one compile-time mirror).

   Definition Classes
     Aliases

7. #### abstract def abort(pos: Position, msg: String): Nothing

   Abruptly terminates current macro expansion leaving a note about what happened.

   Abruptly terminates current macro expansion leaving a note about what happened. Use `enclosingPosition` if you're in doubt what position to pass to `pos`.

   Definition Classes
     FrontEnds

8. #### abstract def classPath: List[URL]

   Exposes current classpath.

   Exposes current classpath.

   Definition Classes
     Infrastructure

9. #### abstract def compilerSettings: List[String]

   Exposes current compiler settings as a list of options.

   Exposes current compiler settings as a list of options. Use `scalac -help`, `scalac -X` and `scalac -Y` to learn about currently supported options.

   Definition Classes
     Infrastructure

10. #### abstract def echo(pos: Position, msg: String): Unit

    For sending a message which should not be labelled as a warning/error, but also shouldn't require -verbose to be visible.

    For sending a message which should not be labelled as a warning/error, but also shouldn't require -verbose to be visible. Use `enclosingPosition` if you're in doubt what position to pass to `pos`.

    Definition Classes
      FrontEnds

11. #### abstract def enclosingMacros: List[Context]

    Contexts that represent macros in-flight, including the current one.

    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 `enclosingMacros` 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 `openMacros`, this is a val, which means that it gets initialized when the context is created and always stays the same regardless of whatever happens during macro expansion.

    Definition Classes
      Enclosures

12. #### abstract def enclosingPosition: Position

    Tries to guess a position for the enclosing application.

    Tries to guess a position for the enclosing application. But that is simple, right? Just dereference `pos` of `macroApplication`? Not really. If we're in a synthetic macro expansion (no positions), we must do our best to infer the position of something that triggered this expansion. Surprisingly, quite often we can do this by navigation the `enclosingMacros` stack.

    Definition Classes
      Enclosures

13. #### abstract def error(pos: Position, msg: String): Unit

    Emits a compilation error.

    Emits a compilation error. Use `enclosingPosition` if you're in doubt what position to pass to `pos`.

    Definition Classes
      FrontEnds

14. #### abstract def eval[T](expr: Expr[T]): T

    Takes a typed wrapper for a tree of type `T` and evaluates it to a value of type `T`.

    Takes a typed wrapper for a tree of type `T` and evaluates it to a value of type `T`.

    Can be used to perform compile-time computations on macro arguments to the extent permitted by the shape of the arguments.

    Known issues: because of https://issues.scala-lang.org/browse/SI-5748 trees being evaluated first need to undergo `untypecheck`. Resetting symbols and types mutates the tree in place, therefore the conventional approach is to `duplicate` the tree first.

        scala> def impl(c: Context)(x: c.Expr[String]) = {
             | val x1 = c.Expr[String](c.untypecheck(x.tree.duplicate))
             | println(s"compile-time value is: ${c.eval(x1)}")
             | x
             | }
        impl: (c: Context)(x: c.Expr[String])c.Expr[String]

        scala> def test(x: String) = macro impl
        test: (x: String)String

        scala> test("x")
        compile-time value is: x
        res0: String = x

        scala> test("x" + "y")
        compile-time value is: xy
        res1: String = xy

        scala> val x = "x"
        x: String = x

        scala> test(x + "y")
        compile-time value is: xy
        res2: String = xy

        scala> { val x = "x"; test(x + "y") }
        error: exception during macro expansion:
        scala.tools.reflect.ToolBoxError: reflective compilation failed

    Note that in the last case evaluation has failed, because the argument of a macro refers to a runtime value `x`, which is unknown at compile time.

    Definition Classes
      Evals

15. #### abstract def freshName[NameType <: Name](name: NameType): NameType

    Creates a more or less unique name having a given name as a prefix and having the same flavor (term name or type name) as the given name.

    Creates a more or less unique name having a given name as a prefix and having the same flavor (term name or type name) as the given name. Consult scala.reflect.macros.Names for more information on uniqueness of such names.

    Definition Classes
      Names

16. #### abstract def freshName(name: String): String

    Creates a string that represents a more or less unique name having a given prefix.

    Creates a string that represents a more or less unique name having a given prefix. Consult scala.reflect.macros.Names for more information on uniqueness of such names.

    Definition Classes
      Names

17. #### abstract def freshName(): String

    Creates a string that represents a more or less unique name.

    Creates a string that represents a more or less unique name. Consult scala.reflect.macros.Names for more information on uniqueness of such names.

    Definition Classes
      Names

18. #### abstract def hasErrors: Boolean

    Does the compilation session have any errors?

    Does the compilation session have any errors?

    Definition Classes
      FrontEnds

19. #### abstract def hasWarnings: Boolean

    Does the compilation session have any warnings?

    Does the compilation session have any warnings?

    Definition Classes
      FrontEnds

20. #### abstract def inferImplicitValue(pt: Type, silent: Boolean = true, withMacrosDisabled: Boolean = false, pos: Position = enclosingPosition): Tree

    Infers an implicit value of the expected type `pt` in the macro callsite context.

    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, `TypecheckException` 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.

    Definition Classes
      Typers
    Exceptions thrown

21. #### abstract def inferImplicitView(tree: Tree, from: Type, to: Type, silent: Boolean = true, withMacrosDisabled: Boolean = false, pos: Position = enclosingPosition): Tree

    Infers an implicit view from the provided tree `tree` of the type `from` to the type `to` in the macro callsite context.

    Infers an implicit view from the provided tree `tree` of 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.

    If `silent` is false, `TypecheckException` 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.

    Definition Classes
      Typers
    Exceptions thrown

22. #### abstract def info(pos: Position, msg: String, force: Boolean): Unit

    Emits an informational message, suppressed unless `-verbose` or `force=true`.

    Emits an informational message, suppressed unless `-verbose` or `force=true`. Use `enclosingPosition` if you're in doubt what position to pass to `pos`.

    Definition Classes
      FrontEnds

23. #### abstract val internal: ContextInternalApi

    Definition Classes
      Internals
    See also

      scala.reflect.api.Internals

24. #### abstract def macroApplication: Tree

    The tree that undergoes macro expansion.

    The tree that undergoes macro expansion. Can be useful to get an offset or a range position of the entire tree being processed.

    Definition Classes
      Enclosures

25. #### abstract val mirror: Universe.Mirror

    The mirror of the compile-time universe.

26. #### abstract def openMacros: List[Context]

    Contexts that represent macros in-flight, including the current one.

    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.

    Definition Classes
      Typers

27. #### abstract def parse(code: String): Tree

    Parses a string with a Scala expression into an abstract syntax tree.

    Parses a string with a Scala expression into an abstract syntax tree. Only works for expressions, i.e. parsing a package declaration will fail.

    Definition Classes
      Parsers
    Exceptions thrown

28. #### abstract val prefix: Expr[PrefixType]

    The prefix tree from which the macro is selected.

    The prefix tree from which the macro is selected.

    For example, for a macro `filter` defined as an instance method on a collection `Coll`, `prefix` represents an equivalent of `this` for normal instance methods:

        scala> class Coll[T] {
             | def filter(p: T => Boolean): Coll[T] = macro M.filter[T]
             | }; object M {
             | def filter[T](c: Context { type PrefixType = Coll[T] })
             |              (p: c.Expr[T => Boolean]): c.Expr[Coll[T]] =
             |   {
             |     println(c.prefix.tree)
             |     c.prefix
             |   }
             | }
        defined class Coll
        defined module Macros

        scala> new Coll[Int]().filter(_ % 2 == 0)
        new Coll[Int]()
        res0: Coll[Int] = ...

        scala> val x = new Coll[String]()
        x: Coll[String] = ...

        scala> x.filter(_ != "")
        $line11.$read.$iw.$iw.$iw.$iw.$iw.$iw.$iw.$iw.$iw.$iw.$iw.$iw.x
        res1 @ 35563b4b: x.type = ...

    Note how the value of `prefix` changes depending on the qualifier of the macro call (i.e. the expression that is at the left-hand side of the dot).

    Another noteworthy thing about the snippet above is the `Context { type PrefixType = Coll[T] }` type that is used to stress that the macro implementation works with prefixes of type `Coll[T]`.

29. #### abstract def reifyEnclosingRuntimeClass: Tree

    Given a type, generate a tree that when compiled and executed produces the runtime class of the enclosing class or module.

    Given a type, generate a tree that when compiled and executed produces the runtime class of the enclosing class or module. Returns `EmptyTree` if there does not exist an enclosing class or module.

    Definition Classes
      Reifiers

30. #### abstract def reifyRuntimeClass(tpe: Type, concrete: Boolean = true): Tree

    Given a type, generate a tree that when compiled and executed produces the runtime class of the original type.

    Given a type, generate a tree that when compiled and executed produces the runtime class of the original type. If `concrete` is true, then this function will bail on types, who refer to abstract types (like `ClassTag` does).

    Definition Classes
      Reifiers

31. #### abstract def reifyTree(universe: Tree, mirror: Tree, tree: Tree): Tree

    Given a tree, generate a tree that when compiled and executed produces the original tree.

    Given a tree, generate a tree that when compiled and executed produces the original tree. For more information and examples see the documentation for `Universe.reify`.

    The produced tree will be bound to the specified `universe` and `mirror`. Possible values for `universe` include `universe.internal.gen.mkRuntimeUniverseRef`. Possible values for `mirror` include `EmptyTree` (in that case the reifier will automatically pick an appropriate mirror).

    This function is deeply connected to `Universe.reify`, a macro that reifies arbitrary expressions into runtime trees. They do very similar things (`Universe.reify` calls `Context.reifyTree` to implement itself), but they operate on different metalevels (see below).

    Let's study the differences between `Context.reifyTree` and `Universe.reify` on an example of using them inside a `fooMacro` macro:

    * Since reify itself is a macro, it will be executed when fooMacro is being compiled (metalevel -1) and will produce a tree that when evaluated during macro expansion of fooMacro (metalevel 0) will recreate the input tree.

    This provides a facility analogous to quasi-quoting. Writing "reify{ expr }" will generate an AST that represents expr. Afterwards this AST (or its parts) can be used to construct the return value of fooMacro.

    * reifyTree is evaluated during macro expansion (metalevel 0) and will produce a tree that when evaluated during the runtime of the program (metalevel 1) will recreate the input tree.

    This provides a way to retain certain trees from macro expansion time to be inspected later, in the runtime. For example, DSL authors may find it useful to capture DSL snippets into ASTs that are then processed at runtime in a domain-specific way.

    Also note the difference between universes of the runtime trees produced by two reifies:

    * The result of compiling and running the result of reify will be bound to the Universe that called reify. This is possible because it's a macro, so it can generate whatever code it wishes.

    * The result of compiling and running the result of reifyTree will be the `prefix` that needs to be passed explicitly. This happens because the Universe of the evaluated result is from a different metalevel than the Context the called reify.

    Typical usage of this function is to retain some of the trees received/created by a macro into the form that can be inspected (via pattern matching) or compiled/run (by a reflective ToolBox) during the runtime.

    Definition Classes
      Reifiers

32. #### abstract def reifyType(universe: Tree, mirror: Tree, tpe: Type, concrete: Boolean = false): Tree

    Given a type, generate a tree that when compiled and executed produces the original type.

    Given a type, generate a tree that when compiled and executed produces the original type. The produced tree will be bound to the specified `universe` and `mirror`. For more information and examples see the documentation for `Context.reifyTree` and `Universe.reify`.

    Definition Classes
      Reifiers

33. #### abstract def settings: List[String]

    Exposes macro-specific settings as a list of strings.

    Exposes macro-specific settings as a list of strings. These settings are passed to the compiler via the "-Xmacro-settings:setting1,setting2...,settingN" command-line option.

    Definition Classes
      Infrastructure

34. #### abstract def typecheck(tree: Tree, mode: TypecheckMode = TERMmode, pt: Type = universe.WildcardType, silent: Boolean = false, withImplicitViewsDisabled: Boolean = false, withMacrosDisabled: Boolean = false): Tree

    Typechecks the provided tree against the expected type `pt` in the macro callsite context under typechecking mode specified in `mode` with EXPRmode being default.

    Typechecks the provided tree against the expected type `pt` in the macro callsite context under typechecking mode specified in `mode` with EXPRmode being default. This populates symbols and types of the tree and possibly transforms it to reflect certain desugarings.

    If `silent` is false, `TypecheckException` 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-verbose. 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

    Definition Classes
      Typers
    Exceptions thrown

35. #### abstract val universe: Universe

    The compile-time universe.

36. #### abstract def unreifyTree(tree: Tree): Tree

    Undoes reification of a tree.

    Undoes reification of a tree.

    This reversion doesn't simply restore the original tree (that would lose the context of reification), but does something more involved that conforms to the following laws:

    1) unreifyTree(reifyTree(tree)) != tree // unreified tree is tree + saved context // in current implementation, the result of unreify is opaque // i.e. there's no possibility to inspect underlying tree/context

    2) reifyTree(unreifyTree(reifyTree(tree))) == reifyTree(tree) // the result of reifying a tree in its original context equals to // the result of reifying a tree along with its saved context

    3) compileAndEval(unreifyTree(reifyTree(tree))) ~ compileAndEval(tree) // at runtime original and unreified trees are behaviorally equivalent

    Definition Classes
      Reifiers

37. #### abstract def untypecheck(tree: Tree): Tree

    In the current implementation of Scala's reflection API, untyped trees (also known as parser trees or unattributed trees) are observationally different from typed trees (also known as typer trees, typechecked trees or attributed trees),

    In the current implementation of Scala's reflection API, untyped trees (also known as parser trees or unattributed trees) are observationally different from typed trees (also known as typer trees, typechecked trees or attributed trees),

    Usually, if some compiler API takes a tree, then both untyped and typed trees will do. However in some cases, only untyped or only typed trees are appropriate. For example, eval only accepts untyped trees and one can only splice typed trees inside typed trees. Therefore in the current reflection API, there is a need in functions that go back and forth between untyped and typed trees. For this we have typecheck and `untypecheck`.

    Note that `untypecheck` is currently afflicted by https://issues.scala-lang.org/browse/SI-5464, which makes it sometimes corrupt trees so that they don't make sense anymore. Unfortunately, there's no workaround for that. We plan to fix this issue soon, but for now please keep it in mind.

    Definition Classes
      Typers
    See also

      http://stackoverflow.com/questions/20936509/scala-macros-what-is-the-difference-between-typed-aka-typechecked-an-untyped

38. #### abstract def warning(pos: Position, msg: String): Unit

    Emits a warning.

    Emits a warning. Use `enclosingPosition` if you're in doubt what position to pass to `pos`.

    Definition Classes
      FrontEnds

39. #### abstract def enclosingClass: Tree

    Tree that corresponds to the enclosing class, or EmptyTree if not applicable.

    Tree that corresponds to the enclosing class, or EmptyTree if not applicable.

    Definition Classes
      Enclosures
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) c.enclosingTree-style APIs are now deprecated; consult the scaladoc for more information

    See also

      scala.reflect.macros.Enclosures

40. #### abstract def enclosingDef: Universe.DefDef

    Tree that corresponds to the enclosing DefDef tree.

    Tree that corresponds to the enclosing DefDef tree. Throws `EnclosureException` if there's no such enclosing tree.

    Definition Classes
      Enclosures
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) c.enclosingTree-style APIs are now deprecated; consult the scaladoc for more information

    See also

      scala.reflect.macros.Enclosures

41. #### abstract def enclosingImpl: Universe.ImplDef

    Tree that corresponds to the enclosing ImplDef tree (i.e.

    Tree that corresponds to the enclosing ImplDef tree (i.e. either ClassDef or ModuleDef). Throws `EnclosureException` if there's no such enclosing tree.

    Definition Classes
      Enclosures
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) c.enclosingTree-style APIs are now deprecated; consult the scaladoc for more information

    See also

      scala.reflect.macros.Enclosures

42. #### abstract def enclosingMethod: Tree

    Tree that corresponds to the enclosing method, or EmptyTree if not applicable.

    Tree that corresponds to the enclosing method, or EmptyTree if not applicable.

    Definition Classes
      Enclosures
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) c.enclosingTree-style APIs are now deprecated; consult the scaladoc for more information

    See also

      scala.reflect.macros.Enclosures

43. #### abstract def enclosingPackage: Universe.PackageDef

    Tree that corresponds to the enclosing PackageDef tree.

    Tree that corresponds to the enclosing PackageDef tree. Throws `EnclosureException` if there's no such enclosing tree.

    Definition Classes
      Enclosures
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) c.enclosingTree-style APIs are now deprecated; consult the scaladoc for more information

    See also

      scala.reflect.macros.Enclosures

44. #### abstract def enclosingRun: Run

    Compilation run that contains this macro application.

    Compilation run that contains this macro application.

    Definition Classes
      Enclosures
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) c.enclosingTree-style APIs are now deprecated; consult the scaladoc for more information

    See also

      scala.reflect.macros.Enclosures

45. #### abstract def enclosingTemplate: Universe.Template

    Tree that corresponds to the enclosing Template tree.

    Tree that corresponds to the enclosing Template tree. Throws `EnclosureException` if there's no such enclosing tree.

    Definition Classes
      Enclosures
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) c.enclosingTree-style APIs are now deprecated; consult the scaladoc for more information

    See also

      scala.reflect.macros.Enclosures

46. #### abstract def enclosingUnit: CompilationUnit

    Compilation unit that contains this macro application.

    Compilation unit that contains this macro application.

    Definition Classes
      Enclosures
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) c.enclosingTree-style APIs are now deprecated; consult the scaladoc for more information

    See also

      scala.reflect.macros.Enclosures

47. #### abstract def fresh[NameType <: Name](name: NameType): NameType

    Creates a more or less unique name having a given name as a prefix and having the same flavor (term name or type name) as the given name.

    Creates a more or less unique name having a given name as a prefix and having the same flavor (term name or type name) as the given name. Consult scala.reflect.macros.Names for more information on uniqueness of such names.

    Definition Classes
      Names
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) Use freshName instead

48. #### abstract def fresh(name: String): String

    Creates a string that represents a more or less unique name having a given prefix.

    Creates a string that represents a more or less unique name having a given prefix. Consult scala.reflect.macros.Names for more information on uniqueness of such names.

    Definition Classes
      Names
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) Use freshName instead

49. #### abstract def fresh(): String

    Creates a string that represents a more or less unique name.

    Creates a string that represents a more or less unique name. Consult scala.reflect.macros.Names for more information on uniqueness of such names.

    Definition Classes
      Names
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) Use freshName instead

50. #### abstract def literal(x: Char): Expr[Char]

    Shorthand for `Literal(Constant(x: Char))` in the underlying `universe`.

    Shorthand for `Literal(Constant(x: Char))` in the underlying `universe`.

    Definition Classes
      ExprUtils
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) Use quasiquotes instead

51. #### abstract def literal(x: String): Expr[String]

    Shorthand for `Literal(Constant(x: String))` in the underlying `universe`.

    Shorthand for `Literal(Constant(x: String))` in the underlying `universe`.

    Definition Classes
      ExprUtils
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) Use quasiquotes instead

52. #### abstract def literal(x: Double): Expr[Double]

    Shorthand for `Literal(Constant(x: Double))` in the underlying `universe`.

    Shorthand for `Literal(Constant(x: Double))` in the underlying `universe`.

    Definition Classes
      ExprUtils
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) Use quasiquotes instead

53. #### abstract def literal(x: Float): Expr[Float]

    Shorthand for `Literal(Constant(x: Float))` in the underlying `universe`.

    Shorthand for `Literal(Constant(x: Float))` in the underlying `universe`.

    Definition Classes
      ExprUtils
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) Use quasiquotes instead

54. #### abstract def literal(x: Long): Expr[Long]

    Shorthand for `Literal(Constant(x: Long))` in the underlying `universe`.

    Shorthand for `Literal(Constant(x: Long))` in the underlying `universe`.

    Definition Classes
      ExprUtils
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) Use quasiquotes instead

55. #### abstract def literal(x: Int): Expr[Int]

    Shorthand for `Literal(Constant(x: Int))` in the underlying `universe`.

    Shorthand for `Literal(Constant(x: Int))` in the underlying `universe`.

    Definition Classes
      ExprUtils
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) Use quasiquotes instead

56. #### abstract def literal(x: Short): Expr[Short]

    Shorthand for `Literal(Constant(x: Short))` in the underlying `universe`.

    Shorthand for `Literal(Constant(x: Short))` in the underlying `universe`.

    Definition Classes
      ExprUtils
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) Use quasiquotes instead

57. #### abstract def literal(x: Byte): Expr[Byte]

    Shorthand for `Literal(Constant(x: Byte))` in the underlying `universe`.

    Shorthand for `Literal(Constant(x: Byte))` in the underlying `universe`.

    Definition Classes
      ExprUtils
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) Use quasiquotes instead

58. #### abstract def literal(x: Boolean): Expr[Boolean]

    Shorthand for `Literal(Constant(x: Boolean))` in the underlying `universe`.

    Shorthand for `Literal(Constant(x: Boolean))` in the underlying `universe`.

    Definition Classes
      ExprUtils
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) Use quasiquotes instead

59. #### abstract def literalFalse: Expr[Boolean]

    Shorthand for `Literal(Constant(false))` in the underlying `universe`.

    Shorthand for `Literal(Constant(false))` in the underlying `universe`.

    Definition Classes
      ExprUtils
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) Use quasiquotes instead

60. #### abstract def literalNull: Expr[Null]

    Shorthand for `Literal(Constant(null))` in the underlying `universe`.

    Shorthand for `Literal(Constant(null))` in the underlying `universe`.

    Definition Classes
      ExprUtils
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) Use quasiquotes instead

61. #### abstract def literalTrue: Expr[Boolean]

    Shorthand for `Literal(Constant(true))` in the underlying `universe`.

    Shorthand for `Literal(Constant(true))` in the underlying `universe`.

    Definition Classes
      ExprUtils
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) Use quasiquotes instead

62. #### abstract def literalUnit: Expr[Unit]

    Shorthand for `Literal(Constant(()))` in the underlying `universe`.

    Shorthand for `Literal(Constant(()))` in the underlying `universe`.

    Definition Classes
      ExprUtils
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) Use quasiquotes instead

63. #### abstract def resetLocalAttrs(tree: Tree): Tree

    Recursively resets locally defined symbols and types in a given tree.

    Recursively resets locally defined symbols and types in a given tree. WARNING: Don't use this API, go for untypecheck instead.

    Definition Classes
      Typers
    Annotations
      @deprecated
    Deprecated

      (Since version 2.11.0) Use `c.untypecheck` instead

### Concrete Value Members

1. #### final def !=(arg0: Any): Boolean

   Test two objects for inequality.

   Test two objects for inequality.

   returns

     `true` if !(this == that), false otherwise.

   Definition Classes
     AnyRef → Any

2. #### final def ##(): Int

   Equivalent to `x.hashCode` except for boxed numeric types and `null`.

   Equivalent to `x.hashCode` except for boxed numeric types and `null`. For numerics, it returns a hash value which is consistent with value equality: if two value type instances compare as true, then ## will produce the same hash value for each of them. For `null` returns a hashcode where `null.hashCode` throws a `NullPointerException`.

   returns

     a hash value consistent with ==

   Definition Classes
     AnyRef → Any

3. #### def +(other: String): String

   Implicit information
     This member is added by an implicit conversion from Context to any2stringadd[Context] performed by method any2stringadd in scala.Predef.
   Definition Classes
     any2stringadd

4. #### def ->[B](y: B): (Context, B)

   Implicit information
     This member is added by an implicit conversion from Context to ArrowAssoc[Context] performed by method ArrowAssoc in scala.Predef.
   Definition Classes
     ArrowAssoc
   Annotations
     @inline()

5. #### final def ==(arg0: Any): Boolean

   The expression `x == that` is equivalent to `if (x eq null) that eq null else x.equals(that)`.

   The expression `x == that` is equivalent to `if (x eq null) that eq null else x.equals(that)`.

   returns

     `true` if the receiver object is equivalent to the argument; `false` otherwise.

   Definition Classes
     AnyRef → Any

6. #### val Expr: Universe.Expr.type

   Constructor/Extractor for `Expr`.

   Constructor/Extractor for `Expr`.

   Definition Classes
     Aliases

7. #### val TypeTag: Universe.TypeTag.type

   Constructor/Extractor for `TypeTag`.

   Constructor/Extractor for `TypeTag`.

   Definition Classes
     Aliases

8. #### val TypecheckException: macros.TypecheckException.type

   Definition Classes
     Typers
   See also

     `scala.reflect.macros.TypecheckException`

9. #### val WeakTypeTag: Universe.WeakTypeTag.type

   Constructor/Extractor for `WeakTypeTag`.

   Constructor/Extractor for `WeakTypeTag`.

   Definition Classes
     Aliases

10. #### final def asInstanceOf[T0]: T0

    Cast the receiver object to be of type `T0`.

    Cast the receiver object to be of type `T0`.

    Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression `1.asInstanceOf[String]` will throw a `ClassCastException` at runtime, while the expression `List(1).asInstanceOf[List[String]]` will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested type.

    returns

      the receiver object.

    Definition Classes
      Any
    Exceptions thrown

      `ClassCastException` if the receiver object is not an instance of the erasure of type `T0`.

11. #### def clone(): AnyRef

    Create a copy of the receiver object.

    Create a copy of the receiver object.

    The default implementation of the `clone` method is platform dependent.

    returns

      a copy of the receiver object.

    Attributes
      protected[java.lang]
    Definition Classes
      AnyRef
    Annotations
      @HotSpotIntrinsicCandidate() @throws( ... )
    Note

      not specified by SLS as a member of AnyRef

12. #### def ensuring(cond: (Context) ⇒ Boolean, msg: ⇒ Any): Context

    Implicit information
      This member is added by an implicit conversion from Context to Ensuring[Context] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring

13. #### def ensuring(cond: (Context) ⇒ Boolean): Context

    Implicit information
      This member is added by an implicit conversion from Context to Ensuring[Context] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring

14. #### def ensuring(cond: Boolean, msg: ⇒ Any): Context

    Implicit information
      This member is added by an implicit conversion from Context to Ensuring[Context] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring

15. #### def ensuring(cond: Boolean): Context

    Implicit information
      This member is added by an implicit conversion from Context to Ensuring[Context] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring

16. #### final def eq(arg0: AnyRef): Boolean

    Tests whether the argument (`that`) is a reference to the receiver object (`this`).

    Tests whether the argument (`that`) is a reference to the receiver object (`this`).

    The `eq` method implements an equivalence relation on non-null instances of `AnyRef`, and has three additional properties:

    - It is consistent: for any non-null instances `x` and `y` of type `AnyRef`, multiple invocations of `x.eq(y)` consistently returns `true` or consistently returns `false`.
    - For any non-null instance `x` of type `AnyRef`, `x.eq(null)` and `null.eq(x)` returns `false`.
    - `null.eq(null)` returns `true`.

    When overriding the `equals` or `hashCode` methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (`o1 eq o2`), they should be equal to each other (`o1 == o2`) and they should hash to the same value (`o1.hashCode == o2.hashCode`).

    returns

      `true` if the argument is a reference to the receiver object; `false` otherwise.

    Definition Classes
      AnyRef

17. #### def equals(arg0: Any): Boolean

    The equality method for reference types.

    The equality method for reference types. Default implementation delegates to `eq`.

    See also `equals` in scala.Any.

    returns

      `true` if the receiver object is equivalent to the argument; `false` otherwise.

    Definition Classes
      AnyRef → Any

18. #### def formatted(fmtstr: String): String

    Implicit information
      This member is added by an implicit conversion from Context to StringFormat[Context] performed by method StringFormat in scala.Predef.
    Definition Classes
      StringFormat
    Annotations
      @inline()

19. #### final def getClass(): Class[_]

    A representation that corresponds to the dynamic class of the receiver object.

    A representation that corresponds to the dynamic class of the receiver object.

    The nature of the representation is platform dependent.

    returns

      a representation that corresponds to the dynamic class of the receiver object.

    Definition Classes
      AnyRef → Any
    Annotations
      @HotSpotIntrinsicCandidate()
    Note

      not specified by SLS as a member of AnyRef

20. #### def hashCode(): Int

    The hashCode method for reference types.

    The hashCode method for reference types. See hashCode in scala.Any.

    returns

      the hash code value for this object.

    Definition Classes
      AnyRef → Any
    Annotations
      @HotSpotIntrinsicCandidate()

21. #### final def isInstanceOf[T0]: Boolean

    Test whether the dynamic type of the receiver object is `T0`.

    Test whether the dynamic type of the receiver object is `T0`.

    Note that the result of the test is modulo Scala's erasure semantics. Therefore the expression `1.isInstanceOf[String]` will return `false`, while the expression `List(1).isInstanceOf[List[String]]` will return `true`. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the specified type.

    returns

      `true` if the receiver object is an instance of erasure of type `T0`; `false` otherwise.

    Definition Classes
      Any

22. #### final def ne(arg0: AnyRef): Boolean

    Equivalent to `!(this eq that)`.

    Equivalent to `!(this eq that)`.

    returns

      `true` if the argument is not a reference to the receiver object; `false` otherwise.

    Definition Classes
      AnyRef

23. #### final def notify(): Unit

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Definition Classes
      AnyRef
    Annotations
      @HotSpotIntrinsicCandidate()
    Note

      not specified by SLS as a member of AnyRef

24. #### final def notifyAll(): Unit

    Wakes up all threads that are waiting on the receiver object's monitor.

    Wakes up all threads that are waiting on the receiver object's monitor.

    Definition Classes
      AnyRef
    Annotations
      @HotSpotIntrinsicCandidate()
    Note

      not specified by SLS as a member of AnyRef

25. #### def symbolOf[T](implicit arg0: WeakTypeTag[T]): Universe.TypeSymbol

    Type symbol of `x` as derived from a type tag.

    Type symbol of `x` as derived from a type tag.

    Definition Classes
      Aliases

26. #### final def synchronized[T0](arg0: ⇒ T0): T0

    Definition Classes
      AnyRef

27. #### def toString(): String

    Creates a String representation of this object.

    Creates a String representation of this object. The default representation is platform dependent. On the java platform it is the concatenation of the class name, "@", and the object's hashcode in hexadecimal.

    returns

      a String representation of the object.

    Definition Classes
      AnyRef → Any

28. #### def typeOf[T](implicit ttag: TypeTag[T]): Type

    Shortcut for `implicitly[TypeTag[T]].tpe`

    Shortcut for `implicitly[TypeTag[T]].tpe`

    Definition Classes
      Aliases

29. #### def typeTag[T](implicit ttag: TypeTag[T]): TypeTag[T]

    Shortcut for `implicitly[TypeTag[T]]`

    Shortcut for `implicitly[TypeTag[T]]`

    Definition Classes
      Aliases

30. #### final def wait(arg0: Long, arg1: Int): Unit

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

31. #### final def wait(arg0: Long): Unit

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

32. #### final def wait(): Unit

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

33. #### def weakTypeOf[T](implicit attag: WeakTypeTag[T]): Type

    Shortcut for `implicitly[WeakTypeTag[T]].tpe`

    Shortcut for `implicitly[WeakTypeTag[T]].tpe`

    Definition Classes
      Aliases

34. #### def weakTypeTag[T](implicit attag: WeakTypeTag[T]): WeakTypeTag[T]

    Shortcut for `implicitly[WeakTypeTag[T]]`

    Shortcut for `implicitly[WeakTypeTag[T]]`

    Definition Classes
      Aliases

35. #### def →[B](y: B): (Context, B)

    Implicit information
      This member is added by an implicit conversion from Context to ArrowAssoc[Context] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
      ArrowAssoc

### Deprecated Value Members

1. #### def finalize(): Unit

   Called by the garbage collector on the receiver object when there are no more references to the object.

   Called by the garbage collector on the receiver object when there are no more references to the object.

   The details of when and if the `finalize` method is invoked, as well as the interaction between `finalize` and non-local returns and exceptions, are all platform dependent.

   Attributes
     protected[java.lang]
   Definition Classes
     AnyRef
   Annotations
     @Deprecated @deprecated @throws( classOf[java.lang.Throwable] )
   Deprecated

     (Since version ) see corresponding Javadoc for more information.

   Note

     not specified by SLS as a member of AnyRef

2. #### def typeCheck(tree: Tree, pt: Type = universe.WildcardType, silent: Boolean = false, withImplicitViewsDisabled: Boolean = false, withMacrosDisabled: Boolean = false): Tree

   Definition Classes
     Typers
   Annotations
     @deprecated
   Deprecated

     (Since version 2.11.0) Use `c.typecheck` instead

   See also

     `Typers.typecheck`

### Inherited from Internals

### Inherited from ExprUtils

### Inherited from Evals

### Inherited from Parsers

### Inherited from Typers

### Inherited from Infrastructure

### Inherited from FrontEnds

### Inherited from Reifiers

### Inherited from Names

### Inherited from Enclosures

### Inherited from Aliases

### Inherited from AnyRef

### Inherited from Any

### Inherited by implicit conversion any2stringadd from Context to any2stringadd[Context]

### Inherited by implicit conversion StringFormat from Context to StringFormat[Context]

### Inherited by implicit conversion Ensuring from Context to Ensuring[Context]

### Inherited by implicit conversion ArrowAssoc from Context to ArrowAssoc[Context]

### Ungrouped