Simplifications

Author: odersky

compiler/src/dotty/tools/dotc/typer/Applications.scala

@@ -174,7 +174,7 @@ object Applications {
     def productArity: Int = app.productArity
     def productElement(n: Int): Any = app.productElement(n)
   }
-  
+
   /** The unapply method of this extractor also recognizes ExtMethodApplys in closure blocks.
    *  This is necessary to deal with closures as left arguments of extension method applications.
    *  A test case is i5606.scala
@@ -1511,14 +1511,14 @@ trait Applications extends Compatibility { self: Typer with Dynamic =>
 
       case pt @ PolyProto(targs1, pt1) if targs.isEmpty =>
         val alts1 = alts filter pt.isMatchedBy
-        resolveOverloaded(alts1, pt1, targs1.tpes, pos)
+        resolveOverloaded(alts1, pt1, targs1.tpes)
 
       case defn.FunctionOf(args, resultType, _, _) =>
         narrowByTypes(alts, args, resultType)
 
       case pt =>
-        val noSam = alts filter (normalizedCompatible(_, pt))
-        if (noSam.isEmpty) {
+        val compat = alts.filter(normalizedCompatible(_, pt))
+        if (compat.isEmpty)
           /*
            * the case should not be moved to the enclosing match
            * since SAM type must be considered only if there are no candidates
@@ -1528,14 +1528,10 @@ trait Applications extends Compatibility { self: Typer with Dynamic =>
            *   new java.io.ObjectOutputStream(f)
            */
           pt match {
-            case SAMType(mtp) =>
-              val sam = narrowByTypes(alts, mtp.paramInfos, mtp.resultType)
-              if (sam.nonEmpty && !pt.classSymbol.hasAnnotation(defn.FunctionalInterfaceAnnot))
-                ctx.warning(ex"${sam.head.designator} is eta-expanded even though $pt does not have the @FunctionalInterface annotation.", pos)
-              sam
-            case _ => noSam
+            case SAMType(mtp) => narrowByTypes(alts, mtp.paramInfos, mtp.resultType)
+            case _ => compat
           }
-        } else noSam
+        else compat
     }
     val found = narrowMostSpecific(candidates)
     if (found.length <= 1) found
@@ -1544,7 +1540,7 @@ trait Applications extends Compatibility { self: Typer with Dynamic =>
       if (noDefaults.length == 1) noDefaults // return unique alternative without default parameters if it exists
       else {
         val deepPt = pt.deepenProto
-        if (deepPt ne pt) resolveOverloaded(alts, deepPt, targs, pos)
+        if (deepPt ne pt) resolveOverloaded(alts, deepPt, targs)
         else alts
       }
     }

compiler/src/dotty/tools/dotc/typer/Typer.scala

@@ -2481,10 +2481,12 @@ class Typer extends Namer
           !tree.symbol.is(InlineMethod) &&
           !ctx.mode.is(Mode.Pattern) &&
           !(isSyntheticApply(tree) && !isExpandableApply)) {
-        if (!pt.classSymbol.hasAnnotation(defn.FunctionalInterfaceAnnot) &&
-            !defn.isFunctionType(pt) &&
-            SAMType.unapply(pt).isDefined)
-          ctx.warning(ex"${tree.symbol} is eta-expanded even though ${pt.classSymbol} does not have the @FunctionalInterface annotation.", tree.pos)
+        if (!defn.isFunctionType(pt))
+          pt match {
+            case SAMType(_) if !pt.classSymbol.hasAnnotation(defn.FunctionalInterfaceAnnot) =>
+              ctx.warning(ex"${tree.symbol} is eta-expanded even though $pt does not have the @FunctionalInterface annotation.", tree.pos)
+            case _ =>
+          }
         simplify(typed(etaExpand(tree, wtp, arity), pt), pt, locked)
       } else if (wtp.paramInfos.isEmpty && isAutoApplied(tree.symbol))
         readaptSimplified(tpd.Apply(tree, Nil))