the scanner is now less eager about deprecations

When healing braces it isn't very useful to report deprecation warnings,
especially since this process is just simple context-free skimming, which
can't know about what positions can accept what identifiers.

Backport from https://github.com/scala/scala/pull/1807.
Original commit is https://github.com/scala/scala/commit/e5d34d70499504e085ddf957c1c818ffb63f4e8d.

1 files changed, 10 insertions, 1 deletions

diff --git a/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala b/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala
index 4f564c5d0b..00d4d57b34 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala
@@ -113,6 +113,11 @@ trait Scanners extends ScannersCommon {
       cbuf.append(c)
     }
 
+    /** Determines whether this scanner should emit identifier deprecation warnings,
+     *  e.g. when seeing `macro` or `then`, which are planned to become keywords in future versions of Scala.
+     */
+    protected def emitIdentifierDeprecationWarnings = true
+
     /** Clear buffer and set name and token */
     private def finishNamed(idtoken: Int = IDENTIFIER) {
       name = newTermName(cbuf.toString)
@@ -122,7 +127,7 @@ trait Scanners extends ScannersCommon {
         val idx = name.start - kwOffset
         if (idx >= 0 && idx < kwArray.length) {
           token = kwArray(idx)
-          if (token == IDENTIFIER && allowIdent != name)
+          if (token == IDENTIFIER && allowIdent != name && emitIdentifierDeprecationWarnings)
             deprecationWarning(name+" is now a reserved word; usage as an identifier is deprecated")
         }
       }
@@ -1488,6 +1493,10 @@ trait Scanners extends ScannersCommon {
     def improves(patches1: List[BracePatch]): Boolean =
       imbalanceMeasure > new ParensAnalyzer(unit, patches1).imbalanceMeasure
 
+    // don't emit deprecation warnings about identifiers like `macro` or `then`
+    // when skimming through the source file trying to heal braces
+    override def emitIdentifierDeprecationWarnings = false
+
     override def error(offset: Int, msg: String) {}
   }
 }