Fail more gracefully on > 22 case class paramet...

Fail more gracefully on > 22 case class parameters. Closes #3631, no
review.

1 files changed, 8 insertions, 7 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/Namers.scala b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
index d56b8ed944..2123a00550 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Namers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
@@ -287,13 +287,11 @@ trait Namers { self: Analyzer =>
      *  class definition tree.
      *  @return the companion object symbol.
      */
-    def ensureCompanionObject(tree: ClassDef, creator: => Tree): Symbol = {
-      val m: Symbol = context.scope.lookup(tree.name.toTermName).filter(! _.isSourceMethod)
-      if (m.isModule && inCurrentScope(m) && currentRun.compiles(m)) m
-      else
-        /*util.trace("enter synthetic companion object for "+currentRun.compiles(m)+":")*/(
-        enterSyntheticSym(creator))
-    }
+     def ensureCompanionObject(tree: ClassDef, creator: => Tree): Symbol = {
+       val m: Symbol = context.scope.lookup(tree.name.toTermName).filter(! _.isSourceMethod)
+       if (m.isModule && inCurrentScope(m) && currentRun.compiles(m)) m
+       else enterSyntheticSym(creator)
+     }
 
     private def enterSymFinishWith(tree: Tree, tparams: List[TypeDef]) {
       val sym = tree.symbol
@@ -350,6 +348,9 @@ trait Namers { self: Analyzer =>
             tree.symbol = enterClassSymbol(tree)
             finishWith(tparams)
             if (mods.isCase) {
+              if (treeInfo.firstConstructorArgs(impl.body).size > MaxFunctionArity)
+                context.error(tree.pos, "Implementation restriction: case classes cannot have more than " + MaxFunctionArity + " parameters.")
+
               val m = ensureCompanionObject(tree, caseModuleDef(tree))
               caseClassOfModuleClass(m.moduleClass) = tree
             }