More tests

and a typo fixed

Author: odersky

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

@@ -1312,7 +1312,7 @@ class TypeComparer(initctx: Context) extends DotClass with ConstraintHandling {
     case tp1: RefinedType =>
       tp2 match {
         case tp2: RefinedType if tp1.refinedName == tp2.refinedName =>
-          // Given two refinements `T1 { X = S1 }` and `T2 { X = S2 }` rwrite to
+          // Given two refinements `T1 { X = S1 }` and `T2 { X = S2 }` rewrite to
           // `T1 & T2 { X B }` where `B` is the conjunction of the bounds of `X` in `T1` and `T2`.
           //
           // However, if `homogenizeArgs` is set, and both aliases `X = Si` are

tests/pos/t5070.scala

@@ -13,3 +13,26 @@ class Test {
 
   implicitly[a.T](b(a)) // works
 }
+
+
+class ImplicitVsTypeAliasTezt {
+
+    class Monad[m[_]] {
+        type For[a] = _For[m, a]
+        implicit def toFor[a](m: m[a]): For[a] = throw new Error("todo") // lookup fails
+//        implicit def toFor[a](m: m[a]): _For[m, a] = throw new Error("todo") // fine.
+    }
+
+    trait _For[m[_], a] {
+        def map[b](p: a => b): m[b]
+    }
+
+    def useMonad[m[_], a](m: m[a])(implicit i: Monad[m]) = {
+        import i._
+
+        // value map is not a member of type parameter m[a]
+        for {
+            x <- m
+        } yield x.toString
+    }
+}

tests/pos/t5643.scala

@@ -0,0 +1,19 @@
+object TupledEvidenceTest {
+
+  abstract class TupledEvidence[M[_], T0] { type T = T0 }
+
+  implicit def witnessTuple2[M[_], T1, T2](implicit ev1: M[T1], ev2: M[T2]):
+    TupledEvidence[M, (T1, T2)] { type T = (T1, T2) } = sys.error("")
+
+  class GetResult[T]
+
+  implicit val getString: GetResult[String] = new GetResult[String]
+
+  implicit def getTuple[T](implicit w: TupledEvidence[GetResult, T]): GetResult[w.T] = sys.error("")
+
+  def f[T : GetResult] = ""
+
+  f[(String,String)](getTuple[(String, String)])
+
+  f[(String,String)]
+}