Ensure function refinement is dependent

Author: nicolasstucki

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

@@ -1191,12 +1191,13 @@ class Definitions {
   }
 
   object DependentFunctionRefinementOf {
-    /** Matches a refined `FunctionN[...]` or `ContextFunctionN[...]` type and extracts the function type and apply info.
+    /** Matches a dependent refinement of `FunctionN[...]` or `ContextFunctionN[...]` type.
+     *  Extracts the method type type and apply info.
      *
      *  Pattern: `$ft { def apply: $mt }`
      */
     def unapply(ft: Type)(using Context): Option[(Type, MethodType)] = ft.dealias match
-      case RefinedType(parent, nme.apply, mt: MethodType) if isFunctionNType(parent) =>
+      case RefinedType(parent, nme.apply, mt: MethodType) if isFunctionNType(parent) && mt.isResultDependent =>
         Some((parent, mt))
       case _ => None
   }

tests/neg-custom-args/captures/byname.check

@@ -2,7 +2,7 @@
 10 |  h(f2()) // error
    |    ^^^^
    |    Found:    (x$0: Int) ->{cap1} Int
-   |    Required: (x$0: Int) ->{cap2} Int
+   |    Required: Int ->{cap2} Int
    |
    | longer explanation available when compiling with `-explain`
 -- [E007] Type Mismatch Error: tests/neg-custom-args/captures/byname.scala:19:5 ----------------------------------------