Merge pull request #8682 from dotty-staging/paramSymss

Future-proof paramSymss API

Author: nicolasstucki

community-build/community-projects/shapeless

@@ -386,12 +386,15 @@ object SymDenotations {
     final def setParamssFromDefs(tparams: List[TypeDef[?]], vparamss: List[List[ValDef[?]]])(using Context): Unit =
       setParamss(tparams.map(_.symbol), vparamss.map(_.map(_.symbol)))
 
-    /** A pair consisting of type parameter symbols and value parameter symbol lists
-     *  of this method definition, or (Nil, Nil) for other symbols.
+
+    /** The symbols of each type parameter list and value parameter list of this
+     *  method, or Nil if this isn't a method.
+     *
+     *
      *  Makes use of `rawParamss` when present, or constructs fresh parameter symbols otherwise.
      *  This method can be allocation-heavy.
      */
-    final def paramSymss(using ctx: Context): (List[TypeSymbol], List[List[TermSymbol]]) =
+    final def paramSymss(using ctx: Context): List[List[Symbol]] =
 
       def recurWithParamss(info: Type, paramss: List[List[Symbol]]): List[List[Symbol]] =
         info match
@@ -412,17 +415,8 @@ object SymDenotations {
         case _ =>
           Nil
 
-      try
-        val allParamss =
-          if rawParamss.isEmpty then recurWithoutParamss(info)
-          else recurWithParamss(info, rawParamss)
-        val result = info match
-          case info: PolyType => (allParamss.head, allParamss.tail)
-          case _ => (Nil, allParamss)
-        result.asInstanceOf[(List[TypeSymbol], List[List[TermSymbol]])]
-      catch case NonFatal(ex) =>
-        println(i"paramSymss failure for $symbol, $info, $rawParamss")
-        throw ex
+      if rawParamss.isEmpty then recurWithoutParamss(info)
+      else recurWithParamss(info, rawParamss)
     end paramSymss
 
     /** The denotation is completed: info is not a lazy type and attributes have defined values */

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

@@ -339,7 +339,7 @@ private class ExtractAPICollector(implicit ctx: Context) extends ThunkHolder {
   def apiDef(sym: TermSymbol): api.Def = {
     def paramLists(t: Type, paramss: List[List[Symbol]]): List[api.ParameterList] = t match {
       case pt: TypeLambda =>
-        paramLists(pt.resultType, paramss)
+        paramLists(pt.resultType, paramss.drop(1))
       case mt @ MethodTpe(pnames, ptypes, restpe) =>
         assert(paramss.nonEmpty && paramss.head.hasSameLengthAs(pnames),
           i"mismatch for $sym, ${sym.info}, ${sym.paramSymss}")
@@ -359,7 +359,7 @@ private class ExtractAPICollector(implicit ctx: Context) extends ThunkHolder {
       case _ =>
         Nil
     }
-    val vparamss = paramLists(sym.info, sym.paramSymss._2)
+    val vparamss = paramLists(sym.info, sym.paramSymss)
     val retTp = sym.info.finalResultType.widenExpr
 
     api.Def.of(sym.name.toString, apiAccess(sym), apiModifiers(sym),

compiler/src/dotty/tools/dotc/sbt/ExtractAPI.scala

@@ -1749,7 +1749,7 @@ class ReflectionCompilerInterface(val rootContext: core.Contexts.Context) extend
   private def isMethod(sym: Symbol)(using ctx: Context): Boolean =
     sym.isTerm && sym.is(Flags.Method) && !sym.isConstructor
 
-  def Symbol_paramSymss(self: Symbol)(using ctx: Context): (List[Symbol], List[List[Symbol]]) =
+  def Symbol_paramSymss(self: Symbol)(using ctx: Context): List[List[Symbol]] =
     self.paramSymss
 
   def Symbol_primaryConstructor(self: Symbol)(using Context): Symbol =

compiler/src/dotty/tools/dotc/tastyreflect/ReflectionCompilerInterface.scala

@@ -2223,10 +2223,10 @@ class Reflection(private[scala] val internal: CompilerInterface) { self =>
     def methods(using ctx: Context): List[Symbol] =
       internal.Symbol_methods(sym)
 
-    /** A pair consisting of type parameter symbols and value parameter symbol lists
-     *  of this method definition, or (Nil, Nil) for other symbols.
+    /** The symbols of each type parameter list and value parameter list of this
+     *  method, or Nil if this isn't a method.
      */
-    def paramSymss(using ctx: Context): (List[Symbol], List[List[Symbol]]) =
+    def paramSymss(using ctx: Context): List[List[Symbol]] =
       internal.Symbol_paramSymss(sym)
 
     /** The primary constructor of a class or trait, `noSymbol` if not applicable. */

library/src/scala/tasty/Reflection.scala

@@ -1305,10 +1305,10 @@ trait CompilerInterface {
   /** Get all non-private methods declared or inherited */
   def Symbol_methods(self: Symbol)(using ctx: Context): List[Symbol]
 
-  /** A pair consisting of type parameter symbols and value parameter symbol lists
-   *  of this method definition, or (Nil, Nil) for other symbols.
+  /** The symbols of each type parameter list and value parameter list of this
+   *  method, or Nil if this isn't a method.
    */
-  def Symbol_paramSymss(self: Symbol)(using ctx: Context): (List[Symbol], List[List[Symbol]])
+  def Symbol_paramSymss(self: Symbol)(using ctx: Context): List[List[Symbol]]
 
   /** The primary constructor of a class or trait, `noSymbol` if not applicable. */
   def Symbol_primaryConstructor(self: Symbol)(using Context): Symbol

library/src/scala/tasty/reflect/CompilerInterface.scala

@@ -1,28 +1,21 @@
 sym: Test$.a
-tparams: List()
-vparamss: List()
+paramSymss: List()
 
 sym: Test$.b
-tparams: List()
-vparamss: List(List(Test$._$i))
+paramSymss: List(List(Test$._$i))
 
 sym: Test$.c
-tparams: List()
-vparamss: List(List(Test$._$x), List(Test$._$y), List(Test$._$z))
+paramSymss: List(List(Test$._$x), List(Test$._$y), List(Test$._$z))
 
 sym: Test$.d
-tparams: List(Test$._$T)
-vparamss: List()
+paramSymss: List(List(Test$._$T))
 
 sym: Test$.c
-tparams: List(Test$._$T, Test$._$U)
-vparamss: List(List(Test$._$x, Test$._$x2), List(Test$._$y), List(Test$._$z))
+paramSymss: List(List(Test$._$T, Test$._$U), List(Test$._$x, Test$._$x2), List(Test$._$y), List(Test$._$z))
 
 sym: Test.<init>
-tparams: List(Test._$T)
-vparamss: List(List(Test._$a))
+paramSymss: List(List(Test._$T), List(Test._$a))
 
 sym: Test.<init>
-tparams: List(Test._$T)
-vparamss: List(List(Test._$a, Test._$b))
+paramSymss: List(List(Test._$T), List(Test._$a, Test._$b))
 

tests/run-macros/paramSymss.check

@@ -6,9 +6,7 @@ inline def showParamSyms(inline x: Any): String =
 def showParamSymsExpr(using QuoteContext)(x: Expr[Any]): Expr[String] =
   val '{ $y: Any } = x // Drop Inlined not to access the symbol
   val sym = y.unseal.symbol
-  val (tparams, vparamss) = sym.paramSymss
   Expr(
     s"""sym: ${sym.show}
-       |tparams: ${tparams.map(_.show)}
-       |vparamss: ${vparamss.map(_.map(_.show))}
+       |paramSymss: ${sym.paramSymss.map(_.map(_.show))}
        |""".stripMargin)