Merge pull request #566 from lrytz/wip/t4928

Fix SI-4928

5 files changed, 36 insertions, 18 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/ContextErrors.scala b/src/compiler/scala/tools/nsc/typechecker/ContextErrors.scala
index 0c1638b76f..df0258832c 100644
--- a/src/compiler/scala/tools/nsc/typechecker/ContextErrors.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/ContextErrors.scala
@@ -1040,8 +1040,12 @@ trait ContextErrors {
       setError(arg)
     }
 
-    def DoubleParamNamesDefaultError(arg: Tree, name: Name)(implicit context: Context) = {
-      issueNormalTypeError(arg, "parameter specified twice: "+ name)
+    def DoubleParamNamesDefaultError(arg: Tree, name: Name, pos: Int, otherName: Option[Name])(implicit context: Context) = {
+      val annex = otherName match {
+        case Some(oName) => "\nNote that that '"+ oName +"' is not a parameter name of the invoked method."
+        case None => ""
+      }
+      issueNormalTypeError(arg, "parameter '"+ name +"' is already specified at parameter position "+ pos + annex)
       setError(arg)
     }
 
diff --git a/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala b/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala
index 8ae254d35d..9e6b9617a5 100644
--- a/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala
@@ -507,7 +507,7 @@ trait NamesDefaults { self: Analyzer =>
     // maps indices from (order written by user) to (order of definition)
     val argPos            = Array.fill(args.length)(-1)
     var positionalAllowed = true
-    val namelessArgs = mapWithIndex(args) { (arg, index) =>
+    val namelessArgs = mapWithIndex(args) { (arg, argIndex) =>
       arg match {
         case arg @ AssignOrNamedArg(Ident(name), rhs) =>
           def matchesName(param: Symbol) = !param.isSynthetic && (
@@ -519,30 +519,35 @@ trait NamesDefaults { self: Analyzer =>
               case _ => false
             })
           )
-          val pos = params indexWhere matchesName
-          if (pos == -1) {
+          val paramPos = params indexWhere matchesName
+          if (paramPos == -1) {
             if (positionalAllowed) {
-              argPos(index) = index
+              argPos(argIndex) = argIndex
               // prevent isNamed from being true when calling doTypedApply recursively,
               // treat the arg as an assignment of type Unit
               Assign(arg.lhs, rhs) setPos arg.pos
             }
             else UnknownParameterNameNamesDefaultError(arg, name)
           }
-          else if (argPos contains pos)
-            DoubleParamNamesDefaultError(arg, name)
-          else if (isAmbiguousAssignment(typer, params(pos), arg))
+          else if (argPos contains paramPos) {
+            val existingArgIndex = argPos.indexWhere(_ == paramPos)
+            val otherName = args(paramPos) match {
+              case AssignOrNamedArg(Ident(oName), rhs) if oName != name => Some(oName)
+              case _ => None
+            }
+            DoubleParamNamesDefaultError(arg, name, existingArgIndex+1, otherName)
+          } else if (isAmbiguousAssignment(typer, params(paramPos), arg))
             AmbiguousReferenceInNamesDefaultError(arg, name)
           else {
             // if the named argument is on the original parameter
             // position, positional after named is allowed.
-            if (index != pos)
+            if (argIndex != paramPos)
               positionalAllowed = false
-            argPos(index) = pos
+            argPos(argIndex) = paramPos
             rhs
           }
         case _ =>
-          argPos(index) = index
+          argPos(argIndex) = argIndex
           if (positionalAllowed) arg
           else PositionalAfterNamedNamesDefaultError(arg)
       }
diff --git a/test/files/neg/names-defaults-neg.check b/test/files/neg/names-defaults-neg.check
index 01bbe2de4e..b5f544c97e 100644
--- a/test/files/neg/names-defaults-neg.check
+++ b/test/files/neg/names-defaults-neg.check
@@ -28,10 +28,10 @@ names-defaults-neg.scala:18: error: not found: value m
 names-defaults-neg.scala:19: error: reference to x is ambiguous; it is both a method parameter and a variable in scope.
   test8(x = 1)
           ^
-names-defaults-neg.scala:22: error: parameter specified twice: a
+names-defaults-neg.scala:22: error: parameter 'a' is already specified at parameter position 1
   test1(1, a = 2)
              ^
-names-defaults-neg.scala:23: error: parameter specified twice: b
+names-defaults-neg.scala:23: error: parameter 'b' is already specified at parameter position 1
   test1(b = 1, b = "2")
                  ^
 names-defaults-neg.scala:26: error: Int does not take parameters
@@ -61,10 +61,10 @@ and  method g in object t7 of type (a: C, b: Int*)String
 match argument types (C)
   t7.g(new C()) // ambigous reference
      ^
-names-defaults-neg.scala:53: error: parameter specified twice: b
+names-defaults-neg.scala:53: error: parameter 'b' is already specified at parameter position 2
   test5(a = 1, b = "dkjl", b = "dkj")
                              ^
-names-defaults-neg.scala:54: error: parameter specified twice: b
+names-defaults-neg.scala:54: error: parameter 'b' is already specified at parameter position 2
   test5(1, "2", b = 3)
                   ^
 names-defaults-neg.scala:55: error: when using named arguments, the vararg parameter has to be specified exactly once
@@ -110,7 +110,7 @@ names-defaults-neg.scala:91: error: deprecated parameter name a has to be distin
 names-defaults-neg.scala:93: warning: the parameter name y has been deprecated. Use b instead.
   deprNam3(y = 10, b = 2)
              ^
-names-defaults-neg.scala:93: error: parameter specified twice: b
+names-defaults-neg.scala:93: error: parameter 'b' is already specified at parameter position 1
   deprNam3(y = 10, b = 2)
                      ^
 names-defaults-neg.scala:98: error: unknown parameter name: m
@@ -122,7 +122,7 @@ names-defaults-neg.scala:131: error: reference to var2 is ambiguous; it is both
 names-defaults-neg.scala:134: error: missing parameter type for expanded function ((x$1) => a = x$1)
   val taf2: Int => Unit = testAnnFun(a = _, b = get("+"))
                                          ^
-names-defaults-neg.scala:135: error: parameter specified twice: a
+names-defaults-neg.scala:135: error: parameter 'a' is already specified at parameter position 1
   val taf3 = testAnnFun(b = _: String, a = get(8))
                                          ^
 names-defaults-neg.scala:136: error: wrong number of parameters; expected = 2
diff --git a/test/files/neg/t4928.check b/test/files/neg/t4928.check
new file mode 100644
index 0000000000..06d4f22522
--- /dev/null
+++ b/test/files/neg/t4928.check
@@ -0,0 +1,5 @@
+t4928.scala:3: error: parameter 'a' is already specified at parameter position 1
+Note that that 'z' is not a parameter name of the invoked method.
+  f(z = 0, a = 1)
+             ^
+one error found
diff --git a/test/files/neg/t4928.scala b/test/files/neg/t4928.scala
new file mode 100644
index 0000000000..17a5980314
--- /dev/null
+++ b/test/files/neg/t4928.scala
@@ -0,0 +1,4 @@
+class C {
+  def f(a: Int, b: Int = 0) = 0
+  f(z = 0, a = 1)
+}