fixed bug 1056: due to mixed use of normalized ...

fixed bug 1056: due to mixed use of normalized and non-normalized types

should normalize types that were previously tested by a predicate that implicitly considered the normalized type. Before, given e.g., type X = Function[String, String], ``X''.isFunctionType  was true (uses symbol, which normalizes), but ``X''.typeArgs.isEmpty (the alias doesn't have any type arguments)

(there are probably more cases like this, for now looked for .typeArgs)

4 files changed, 13 insertions, 5 deletions

diff --git a/src/compiler/scala/tools/nsc/symtab/Types.scala b/src/compiler/scala/tools/nsc/symtab/Types.scala
index de4c8c3fbb..c358188b38 100644
--- a/src/compiler/scala/tools/nsc/symtab/Types.scala
+++ b/src/compiler/scala/tools/nsc/symtab/Types.scala
@@ -1082,6 +1082,14 @@ trait Types {
     }
 
     override def symbol = if (sym.isAliasType) normalize.symbol else sym
+/* @MAT
+whenever you see `tp.symbol.isXXXX' and then act on tp based on that predicate, you're on thin ice,
+as `symbol' (and `prefix') automatically normalize, but the other inspectors don't.
+In other words, even if `tp.normalize.sym.isXXX' is true, `tp.sym.isXXX' may be false (if sym were a public method to access the non-normalized symbol)...
+
+In retrospect, I think `tp.symbol.isXXX' or (worse) `tp.symbol==XXX' should be replaced by `val tp = tp0.asXXX'.
+A type's symbol should never be inspected directly.
+*/
 
     override def bounds: TypeBounds =
       if (sym.isAbstractType) transform(thisInfo.bounds).asInstanceOf[TypeBounds]
diff --git a/src/compiler/scala/tools/nsc/typechecker/Infer.scala b/src/compiler/scala/tools/nsc/typechecker/Infer.scala
index 18b757d981..a0ee58feab 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Infer.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Infer.scala
@@ -45,7 +45,7 @@ trait Infer requires Analyzer {
       case formal => formal
     }
     if (isVarArgs(formals1)) {
-      val ft = formals1.last.typeArgs.head
+      val ft = formals1.last.normalize.typeArgs.head
       formals1.init ::: (for (val i <- List.range(formals1.length - 1, nargs)) yield ft)
     } else formals1
   }
diff --git a/src/compiler/scala/tools/nsc/typechecker/Namers.scala b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
index 4bbd881cb5..969ab1cce2 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Namers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
@@ -793,7 +793,7 @@ trait Namers requires Analyzer {
         if (elemtp =:= tp)
           result = nested
         else if (isFunctionType(tp) &&
-                 (!isFunctionType(elemtp) || tp.typeArgs.length > elemtp.typeArgs.length))
+                 (!isFunctionType(elemtp) || tp.normalize.typeArgs.length > elemtp.normalize.typeArgs.length))
           result = true
         else (tp, elemtp) match {
           case (TypeRef(pre, sym, args), TypeRef(elempre, elemsym, elemargs)) =>
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index 7534df9bbb..38a7bcea62 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -1314,14 +1314,14 @@ trait Typers requires Analyzer {
              pt.symbol == PartialFunctionClass &&
              fun.vparams.length == 1 && fun.body.isInstanceOf[Match])
             && // see bug901 for a reason why next conditions are neeed
-            (pt.typeArgs.length - 1 == fun.vparams.length
+            (pt.normalize.typeArgs.length - 1 == fun.vparams.length
              ||
              fun.vparams.exists(.tpt.isEmpty)))
-          (pt.symbol, pt.typeArgs.init, pt.typeArgs.last)
+          (pt.symbol, pt.normalize.typeArgs.init, pt.normalize.typeArgs.last)
         else
           (FunctionClass(fun.vparams.length), fun.vparams map (x => NoType), WildcardType)
 
-      val (clazz, argpts, respt) = decompose(if (codeExpected) pt.typeArgs.head else pt)
+      val (clazz, argpts, respt) = decompose(if (codeExpected) pt.normalize.typeArgs.head else pt)
 
       if (fun.vparams.length != argpts.length)
         errorTree(fun, "wrong number of parameters; expected = " + argpts.length)