SI-7870 Detect default getter clashes in constructors

Default getters for constructors live in the companion module.
These eluded the check for clashes in default getter names due
to overloading, which aims to give a more user friendly error
than "double definition: meth$default$1".

This commit checks for default getters in the companion module,
in addition to those in the template itself.

1 files changed, 5 insertions, 3 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
index 32e908e03b..61759a9f00 100644
--- a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
@@ -121,13 +121,13 @@ abstract class RefChecks extends InfoTransform with scala.reflect.internal.trans
     var checkedCombinations = Set[List[Type]]()
 
     // only one overloaded alternative is allowed to define default arguments
-    private def checkOverloadedRestrictions(clazz: Symbol): Unit = {
+    private def checkOverloadedRestrictions(clazz: Symbol, defaultClass: Symbol): Unit = {
       // Using the default getters (such as methodName$default$1) as a cheap way of
       // finding methods with default parameters. This way, we can limit the members to
       // those with the DEFAULTPARAM flag, and infer the methods. Looking for the methods
       // directly requires inspecting the parameter list of every one. That modification
       // shaved 95% off the time spent in this method.
-      val defaultGetters     = clazz.info.findMembers(0L, DEFAULTPARAM)
+      val defaultGetters     = defaultClass.info.findMembers(0L, DEFAULTPARAM)
       val defaultMethodNames = defaultGetters map (sym => nme.defaultGetterToMethod(sym.name))
 
       defaultMethodNames.toList.distinct foreach { name =>
@@ -1638,7 +1638,9 @@ abstract class RefChecks extends InfoTransform with scala.reflect.internal.trans
           case Template(parents, self, body) =>
             localTyper = localTyper.atOwner(tree, currentOwner)
             validateBaseTypes(currentOwner)
-            checkOverloadedRestrictions(currentOwner)
+            checkOverloadedRestrictions(currentOwner, currentOwner)
+            // SI-7870 default getters for constructors live in the companion module
+            checkOverloadedRestrictions(currentOwner, currentOwner.companionModule)
             val bridges = addVarargBridges(currentOwner)
             checkAllOverrides(currentOwner)
             checkAnyValSubclass(currentOwner)