SI-7605 Deprecate procedure syntax

This commit covers three cases:
- constructor definitions      (def this {...})
- concrete method definitions  (def foo {...})
- abstract method declarations (def foo)

The deprecation is currently hidden behind -Xfuture pending IDE support
for migrating users from procedures to methods.

1 files changed, 9 insertions, 1 deletions

diff --git a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
index 1d5f35b7d6..07938ec3df 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
@@ -2512,7 +2512,11 @@ self =>
           val vparamss = paramClauses(nme.CONSTRUCTOR, classContextBounds map (_.duplicate), ofCaseClass = false)
           newLineOptWhenFollowedBy(LBRACE)
           val rhs = in.token match {
-            case LBRACE   => atPos(in.offset) { constrBlock(vparamss) }
+            case LBRACE   => {
+              if (settings.future)
+                deprecationWarning(in.offset, "Procedure syntax is deprecated. Convert procedure to method by adding `: Unit =`.")
+              atPos(in.offset) { constrBlock(vparamss) }
+            }
             case _        => accept(EQUALS) ; atPos(in.offset) { constrExpr(vparamss) }
           }
           DefDef(mods, nme.CONSTRUCTOR, List(), vparamss, TypeTree(), rhs)
@@ -2538,10 +2542,14 @@ self =>
         var restype = fromWithinReturnType(typedOpt())
         val rhs =
           if (isStatSep || in.token == RBRACE) {
+            if (settings.future)
+              deprecationWarning(in.lastOffset, "Procedure syntax is deprecated. Convert procedure to method by adding `: Unit`.")
             if (restype.isEmpty) restype = scalaUnitConstr
             newmods |= Flags.DEFERRED
             EmptyTree
           } else if (restype.isEmpty && in.token == LBRACE) {
+            if (settings.future)
+              deprecationWarning(in.offset, "Procedure syntax is deprecated. Convert procedure to method by adding `: Unit =`.")
             restype = scalaUnitConstr
             blockExpr()
           } else {