SI-6814 adds typechecker modes to c.typecheck

As per multiple user requests, this commit introduces a shortcut
to typecheck trees under multiple different modes: terms (EXPRmode,
was exposed in Scala 2.10) and types (TYPEmode).

Looking into the rest of a dozen of internal typechecker modes, to the
best of my knowledge, I can’t find other modes that we could expose.
FUNmode is useful, but very situational. PATTERNmode is useful, but
also situational, because we don’t expand macros inside patterns
except for whitebox extractor macros. The rest (e.g. POLYmode or TAPPmode)
are too low-level.

1 files changed, 7 insertions, 4 deletions

diff --git a/src/compiler/scala/reflect/macros/contexts/Typers.scala b/src/compiler/scala/reflect/macros/contexts/Typers.scala
index c1ab17027f..0c3881fdcf 100644
--- a/src/compiler/scala/reflect/macros/contexts/Typers.scala
+++ b/src/compiler/scala/reflect/macros/contexts/Typers.scala
@@ -1,8 +1,6 @@
 package scala.reflect.macros
 package contexts
 
-import scala.reflect.internal.Mode
-
 trait Typers {
   self: Context =>
 
@@ -10,10 +8,15 @@ trait Typers {
 
   def openImplicits: List[ImplicitCandidate] = callsiteTyper.context.openImplicits.map(_.toImplicitCandidate)
 
+  type TypecheckMode = scala.reflect.internal.Mode
+  val TypecheckMode = scala.reflect.internal.Mode
+  val TERMmode = TypecheckMode.EXPRmode
+  val TYPEmode = TypecheckMode.TYPEmode | TypecheckMode.FUNmode
+
   /**
    * @see [[scala.tools.reflect.ToolBox.typeCheck]]
    */
-  def typecheck(tree: Tree, pt: Type = universe.WildcardType, silent: Boolean = false, withImplicitViewsDisabled: Boolean = false, withMacrosDisabled: Boolean = false): Tree = {
+  def typecheck(tree: Tree, mode: TypecheckMode = TERMmode, pt: Type = universe.WildcardType, silent: Boolean = false, withImplicitViewsDisabled: Boolean = false, withMacrosDisabled: Boolean = false): Tree = {
     macroLogVerbose("typechecking %s with expected type %s, implicit views = %s, macros = %s".format(tree, pt, !withImplicitViewsDisabled, !withMacrosDisabled))
     val context = callsiteTyper.context
     val wrapper1 = if (!withImplicitViewsDisabled) (context.withImplicitsEnabled[Tree] _) else (context.withImplicitsDisabled[Tree] _)
@@ -24,7 +27,7 @@ trait Typers {
     // typechecking uses silent anyways (e.g. in typedSelect), so you'll only waste your time
     // I'd advise fixing the root cause: finding why the context is not set to report errors
     // (also see reflect.runtime.ToolBoxes.typeCheckExpr for a workaround that might work for you)
-    wrapper(callsiteTyper.silent(_.typed(universe.duplicateAndKeepPositions(tree), pt), reportAmbiguousErrors = false) match {
+    wrapper(callsiteTyper.silent(_.typed(universe.duplicateAndKeepPositions(tree), mode, pt), reportAmbiguousErrors = false) match {
       case universe.analyzer.SilentResultValue(result) =>
         macroLogVerbose(result)
         result