Fix #5374: Test of type projections

tests/neg/type-projections.scala

@@ -0,0 +1,26 @@
+class Test {
+  type A
+
+  class Inner {
+    type B
+    type Balias = B
+    type Aalias = A
+    type Intalias = Int
+  }
+
+  type T <: Inner
+  type U = Inner
+
+  def x0: T#B = ???        // error
+  def x1: T#Balias = ???   // error
+  def x2: T#Aalias = ???   // error
+  def x3: T#Intalias = ??? // error
+  def y0: U#B = ???        // ok
+  def y1: U#Balias = ???   // ok
+  def y2: U#Aalias = ???   // ok
+  def y3: U#Intalias = ??? // ok
+  def z0: Inner#B = ???        // ok
+  def z1: Inner#Balias = ???   // ok
+  def z2: Inner#Aalias = ???   // ok
+  def z3: Inner#Intalias = ??? // ok
+}