Add widenTypeOf in ProtoType; fix applyOverloaded

Author: OlivierBlanvillain

compiler/src/dotty/tools/dotc/core/Types.scala

@@ -1002,6 +1002,12 @@ object Types {
       case _ => this
     }
 
+    /** Widen from TypeOf type to its underlying type. */
+    final def widenTypeOf: Type = this match {
+      case tp: TypeOf => tp.underlyingTp
+      case _ => this
+    }
+
     /** Widen type if it is unstable (i.e. an ExprType, or TermRef to unstable symbol */
     final def widenIfUnstable(implicit ctx: Context): Type = stripTypeVar match {
       case tp: ExprType => tp.resultType.widenIfUnstable

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

@@ -38,7 +38,7 @@ object ProtoTypes {
      *    4. `tp` is a numeric subtype of `pt` (this case applies even if implicit conversions are disabled)
      */
     def isCompatible(tp: Type, pt: Type)(implicit ctx: Context): Boolean =
-      (tp.widenExpr relaxed_<:< pt.widenExpr) || viewExists(tp, pt)
+      (tp.widenExpr.widenTypeOf relaxed_<:< pt.widenExpr.widenTypeOf) || viewExists(tp, pt)
 
     /** Test compatibility after normalization in a fresh typerstate. */
     def normalizedCompatible(tp: Type, pt: Type)(implicit ctx: Context) =

tests/neg/dependent-match.scala renamed to tests/pos/dependent-match.scala

@@ -25,8 +25,8 @@ object Test {
     }
 
   // def f1[T <: Foo](t: T): "a" = test(t) // Do we want this?
-  //def f1[T <: Foo](t: T): Any = test(t)
-  def f2(x: Foo): "a"  = test(x, 123)  // error: matches are not supported yet
+  // def f1[T <: Foo](t: T): Any = test(t)
+  def f2(x: Foo): "a" = test(x, 123)
   // def f3(x: String): 1 = test(x)
   test2(1): "a"
   test2(2): "b"