Account for capture dependencies when substituting

Author: Linyxus

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

@@ -3880,7 +3880,8 @@ object Types {
     /** Does one of the parameter types contain references to earlier parameters
      *  of this method type which cannot be eliminated by de-aliasing?
      */
-    def isParamDependent(using Context): Boolean = paramDependencyStatus == TrueDeps
+    def isParamDependent(using Context): Boolean =
+      paramDependencyStatus == TrueDeps || paramDependencyStatus == CaptureDeps
 
     /** Is there a dependency involving a reference in a capture set, but
      *  otherwise no true result dependency?

tests/pos-custom-args/captures/cc-dep-param.scala

@@ -0,0 +1,8 @@
+import language.experimental.captureChecking
+
+trait Foo[T]
+def test(): Unit =
+  val a: Foo[Int]^ = ???
+  val useA: () ->{a} Unit = ???
+  def foo[X](x: Foo[X]^, op: () ->{x} Unit): Unit = ???
+  foo(a, useA)