Fix-17242

tests/neg/cycles.scala

@@ -29,6 +29,11 @@ class E {
   lazy val x: F#T = ???
 }
 
+object CyclicAnnotation {
+  class local(num: Int) extends annotation.StaticAnnotation
+  def f(x: Int @local(x ++ x)) = ??? // error: Cyclic reference involving val x
+}
+
 class T1 {
   type X = (U, U) // error: cycle
   type U = X & Int

tests/neg/singletons.scala

@@ -8,4 +8,6 @@ object Test {
   val sym: 'sym = 'sym // error: an identifier expected, but quoted identifier found
 
   val foo: s"abc" = "abc"  // error: not a legal singleton type
+
+  def path(x: String, z: x.length.type) = ??? // error: Int is not a valid singleton type, since it is not an immutable path
 }

tests/pos/i17242.scala

@@ -0,0 +1,11 @@
+
+class local(num: Int) extends annotation.StaticAnnotation
+class local2(predicate: Boolean) extends annotation.StaticAnnotation
+
+def working1(x: Int)(z: Int @local(x + x)) = ???
+def working2(x: Int, z: Int @local(x)) = ???
+def working3(x: Int, z: Int & x.type ) = ???
+
+
+def failing1(x: Int, z: Int @local(x + x)) = ???    //error: undefined: x.+ # -1: TermRef(TermParamRef(x),+) at typer
+def failing2(x: Int, z: Int @local2(x == x)) = ???  //error: undefined: x.== # -1: TermRef(TermParamRef(x),==) at typer