Partial Functions resisting

src/compiler/scala/reflect/reify/phases/Reshape.scala

@@ -240,7 +240,7 @@ trait Reshape {
         def toScalaAnnotation(jann: ClassfileAnnotArg): Tree = (jann: @unchecked) match {
           case LiteralAnnotArg(const) => Literal(const)
           case ArrayAnnotArg(arr)     => Apply(Ident(definitions.ArrayModule), arr.toList map toScalaAnnotation)
-          case NestedAnnotArg(ann)    => toPreTyperAnnotation(ann)
+          case NestedAnnotArg(naa)    => toPreTyperAnnotation(naa)
         }
 
         ann.assocs map { case (nme, arg) => NamedArg(Ident(nme), toScalaAnnotation(arg)) }

src/compiler/scala/tools/nsc/typechecker/MacroAnnotationNamers.scala

@@ -77,7 +77,7 @@ trait MacroAnnotationNamers { self: Analyzer =>
         sym
       }
       deriveSymbolFromSource(tree) {
-        case tree @ ClassDef(mods, name, _, _) =>
+        case cdef @ ClassDef(mods, name, _, _) =>
           val existing = context.scope.lookup(name)
           val isRedefinition = (
                                existing.isType
@@ -90,10 +90,10 @@ trait MacroAnnotationNamers { self: Analyzer =>
                                )
           val clazz: Symbol = {
             if (isRedefinition) {
-              updatePosFlags(existing, tree.pos, mods.flags)
-              setPrivateWithin(tree, existing)
+              updatePosFlags(existing, cdef.pos, mods.flags)
+              setPrivateWithin(cdef, existing)
               clearRenamedCaseAccessors(existing)
-              tree.symbol = existing
+              cdef.symbol = existing
               existing
             }
             else coreCreateAssignAndEnterSymbol setFlag inConstructorFlag
@@ -111,7 +111,7 @@ trait MacroAnnotationNamers { self: Analyzer =>
             assert(clazz.name.toString.indexOf('(') < 0, clazz.name)  // )
           }
           clazz
-        case tree @ ModuleDef(mods, name, _) =>
+        case mdef @ ModuleDef(mods, name, _) =>
           var m: Symbol = context.scope lookupModule name
           val moduleFlags = mods.flags | MODULE
           // TODO: inCurrentScope(m) check that's present in vanilla Namer is omitted here
@@ -128,16 +128,16 @@ trait MacroAnnotationNamers { self: Analyzer =>
               val packageScope = m.enclosingPackageClass.rawInfo.decls
               packageScope.filter(_.owner != m.enclosingPackageClass).toList.foreach(packageScope unlink _)
             }
-            updatePosFlags(m, tree.pos, moduleFlags)
-            setPrivateWithin(tree, m)
-            m.moduleClass andAlso (setPrivateWithin(tree, _))
+            updatePosFlags(m, mdef.pos, moduleFlags)
+            setPrivateWithin(mdef, m)
+            m.moduleClass andAlso (setPrivateWithin(mdef, _))
             context.unit.synthetics -= m
-            tree.symbol = m
+            mdef.symbol = m
           }
           else {
             m = coreCreateAssignAndEnterSymbol
             m.moduleClass setFlag moduleClassFlags(moduleFlags)
-            setPrivateWithin(tree, m.moduleClass)
+            setPrivateWithin(mdef, m.moduleClass)
           }
           m.moduleClass setInfo namerOf(m).moduleClassTypeCompleter(tree)
           if (m.isTopLevel && !m.hasPackageFlag) {

src/compiler/scala/tools/nsc/typechecker/Macros.scala

@@ -639,7 +639,7 @@ trait Macros extends MacroRuntimes with Traces with Helpers {
       else {
         // approximation is necessary for whitebox macros to guide type inference
         // read more in the comments for onDelayed below
-        val undetparams = tp collect { case tp if tp.typeSymbol.isTypeParameter => tp.typeSymbol }
+        val undetparams = tp collect { case tp1 if tp1.typeSymbol.isTypeParameter => tp1.typeSymbol }
         deriveTypeWithWildcards(undetparams)(tp)
       }
     }

src/library/scala/collection/mutable/ArraySeq.scala

@@ -120,7 +120,7 @@ object ArraySeq extends StrictOptimizedClassTagSeqFactory[ArraySeq] { self =>
    * `ArraySeq.make(a.asInstanceOf[Array[Int]])` does not work, it throws a `ClassCastException`
    * at runtime.
    */
-  def make[T](x: Array[T]): ArraySeq[T] = ((x.asInstanceOf[Array[_]]: @unchecked) match {
+  def make[T](x: Array[T]): ArraySeq[T] = ((x: @unchecked) match {
     case null              => null
     case x: Array[AnyRef]  => new ofRef[AnyRef](x)
     case x: Array[Int]     => new ofInt(x)

src/reflect/scala/reflect/internal/TreeGen.scala

@@ -723,8 +723,7 @@ abstract class TreeGen {
         val valeqs = rest.take(definitions.MaxTupleArity - 1).takeWhile { ValEq.unapply(_).nonEmpty }
         assert(!valeqs.isEmpty, "Missing ValEq")
         val rest1 = rest.drop(valeqs.length)
-        val pats = valeqs.collect { case ValEq(pat, _) => pat }
-        val rhss = valeqs.collect { case ValEq(_, rhs) => rhs }
+        val (pats, rhss) = valeqs.map(ValEq.unapply(_).get).unzip
         val defpat1 = makeBind(pat)
         val defpats = pats map makeBind
         val pdefs = defpats.lazyZip(rhss).flatMap(mkPatDef)

test/files/neg/t11850.check

@@ -19,6 +19,9 @@ t11850.scala:170: warning: Name _1 is already introduced in an enclosing scope a
 t11850.scala:187: warning: Name x is already introduced in an enclosing scope as value x. Did you intend to match it using backquoted `x`?
     case x => x.toString
          ^
+t11850.scala:203: warning: Name c is already introduced in an enclosing scope as value c in class pattern matches occasionally appear in pattern-matching anonymous functions. Did you intend to match it using backquoted `c`?
+  def f = c.collect { case c if c.flag => c.toString }
+                           ^
 error: No warnings can be incurred under -Werror.
-7 warnings
+8 warnings
 1 error

test/files/neg/t11850.scala

@@ -194,3 +194,11 @@ class `lukas asked whats that null check for` {
     case c => false
   }
 }
+case class Collector() {
+  def collect[T](pf: PartialFunction[Collector, T]): List[T] = ???
+  def flag = true
+}
+class `pattern matches occasionally appear in pattern-matching anonymous functions` {
+  val c = Collector()
+  def f = c.collect { case c if c.flag => c.toString }
+}