simplify existing code

Author: rochala

compiler/src/dotty/tools/dotc/util/Signatures.scala

@@ -42,18 +42,16 @@ object Signatures {
   /**
    * Extract (current parameter index, function index, functions) out of a method call.
    *
-   * @param path The path to the function starting with closest one to `span`
+   * @param enclosingApply Enclosing function application
    * @param span The position of the cursor
    * @return A triple containing the index of the parameter being edited, the index of the function
    *         being called, the list of overloads of this function).
    */
-  def callInfo(path: List[tpd.Tree], span: Span)(using Context): (Int, Int, List[SingleDenotation]) =
-    path match {
-      case UnApply(fun, _, patterns) :: _ => callInfo(span, patterns, fun, Signatures.countParams(fun))
-      case Apply(fun, params) :: _ => callInfo(span, params, fun, Signatures.countParams(fun))
-      case _ =>
-        (0, 0, Nil)
-    }
+  def callInfo(enclosingApply: Option[tpd.Tree], span: Span)(using Context): (Int, Int, List[SingleDenotation]) =
+    enclosingApply.map {
+      case UnApply(fun, _, patterns) => callInfo(span, patterns, fun, Signatures.countParams(fun))
+      case Apply(fun, params) => callInfo(span, params, fun, Signatures.countParams(fun))
+    }.getOrElse((0, 0, Nil))
 
   def callInfo(
     span: Span,

language-server/src/dotty/tools/languageserver/DottyLanguageServer.scala

@@ -556,12 +556,13 @@ class DottyLanguageServer extends LanguageServer
 
     val pos = sourcePosition(driver, uri, params.getPosition)
     val trees = driver.openedTrees(uri)
-    val path = Interactive.pathTo(trees, pos).span {
-      case Apply(fun, _) => fun.span.contains(pos.span)
-      case UnApply(fun, _, _) => fun.span.contains(pos.span)
-      case _ => true
+    val path = Interactive.pathTo(trees, pos).find {
+      case Apply(fun, _) => !fun.span.contains(pos.span)
+      case UnApply(fun, _, _) => !fun.span.contains(pos.span)
+      case _ => false
     }
-    val (paramN, callableN, alternatives) = Signatures.callInfo(path._2, pos.span)
+
+    val (paramN, callableN, alternatives) = Signatures.callInfo(path, pos.span)
     val signatureInfos = alternatives.flatMap(Signatures.toSignature)
 
     new SignatureHelp(signatureInfos.map(signatureToSignatureInformation).asJava, callableN, paramN)