SI-8052 Disallow `macro` as an identifier

Note that the change could look a lot cleaner, at the cost of returning
more generic error messages. I decided that at least for 2.11 I'll keep
scalac remembering that macro was a standard identifier name once, so
that we can point out more precisely what's wrong with users' code.

2 files changed, 11 insertions, 4 deletions

diff --git a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
index 91db1bb92a..61ea9230a7 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
@@ -671,6 +671,7 @@ self =>
     def isRawBar  = isIdent && in.name == raw.BAR
 
     def isIdent = in.token == IDENTIFIER || in.token == BACKQUOTED_IDENT
+    def isMacro = in.token == IDENTIFIER && in.name == nme.MACROkw
 
     def isLiteralToken(token: Token) = token match {
       case CHARLIT | INTLIT | LONGLIT | FLOATLIT | DOUBLELIT |
@@ -1038,6 +1039,8 @@ self =>
     def identForType(): TypeName = ident().toTypeName
     def identForType(skipIt: Boolean): TypeName = ident(skipIt).toTypeName
 
+    def identOrMacro(): Name = if (isMacro) rawIdent() else ident()
+
     def selector(t: Tree): Tree = {
       val point = in.offset
       //assert(t.pos.isDefined, t)
@@ -2551,7 +2554,7 @@ self =>
       }
       else {
         val nameOffset = in.offset
-        val name = ident()
+        val name = identOrMacro()
         funDefRest(start, nameOffset, mods, name)
       }
     }
@@ -2584,7 +2587,7 @@ self =>
           } else {
             if (in.token == EQUALS) {
               in.nextTokenAllow(nme.MACROkw)
-              if (in.token == IDENTIFIER && in.name == nme.MACROkw) {
+              if (isMacro) {
                 in.nextToken()
                 newmods |= Flags.MACRO
               }
diff --git a/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala b/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala
index b12be1a056..e488166169 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala
@@ -204,8 +204,12 @@ trait Scanners extends ScannersCommon {
         val idx = name.start - kwOffset
         if (idx >= 0 && idx < kwArray.length) {
           token = kwArray(idx)
-          if (token == IDENTIFIER && allowIdent != name && emitIdentifierDeprecationWarnings)
-            deprecationWarning(name+" is now a reserved word; usage as an identifier is deprecated")
+          if (token == IDENTIFIER && allowIdent != name) {
+            if (name == nme.MACROkw)
+              syntaxError(name+" is now a reserved word; usage as an identifier is disallowed")
+            else if (emitIdentifierDeprecationWarnings)
+              deprecationWarning(name+" is now a reserved word; usage as an identifier is deprecated")
+          }
         }
       }
     }