Generate dummy symbols for refinements

Author: tanishiking

compiler/src/dotty/tools/dotc/semanticdb/SemanticSymbolBuilder.scala

@@ -93,18 +93,22 @@ object SemanticSymbolBuilder:
      */
     def localIdx(sym: Symbol)(using Context): Int =
       val startPos =
-        assert(sym.span.exists, s"$sym should have a span")
-        sym.span.start
+        if sym.span.exists then Some(sym.span.start) else None
+        // assert(sym.span.exists, s"$sym should have a span")
       @tailrec
       def computeLocalIdx(sym: Symbol): Int = locals get sym match
         case Some(idx) => idx
-        case None      => symsAtOffset(startPos).find(_.name == sym.name) match
+        case None      => (for {
+          pos <- startPos
+          samePosSyms <- symsAtOffset.get(pos)
+          sameName <- samePosSyms.find(_.name == sym.name)
+        } yield sameName) match
           case Some(other) => computeLocalIdx(other)
           case None =>
             val idx = nextLocalIdx
             nextLocalIdx += 1
             locals(sym) = idx
-            symsAtOffset(startPos) += sym
+            startPos.foreach(pos => symsAtOffset(pos) += sym)
             idx
       end computeLocalIdx
       computeLocalIdx(sym)

compiler/src/dotty/tools/dotc/semanticdb/SymbolOps.scala

@@ -6,6 +6,7 @@ import core.Symbols._
 import core.Contexts.Context
 import core.Types._
 import core.Annotations.Annotation
+import core.Flags.EmptyFlags
 import ast.tpd._
 
 import dotty.tools.dotc.{semanticdb => s}
@@ -16,11 +17,11 @@ object SymbolOps:
   extension (sym: Symbol)
     def sig(using LinkMode, Context): s.Signature =
       import TypeOps._
+      val sig = sym.info.toSemanticSig(sym)
       println("")
       println(sym.toString)
       println(s"=========sym.info================")
       pprint.pprintln(sym.info)
-      val sig = sym.info.toSemanticSig(sym)
       println(s"=========sig================")
       pprint.pprintln(sig)
       sig
@@ -32,7 +33,9 @@ object TypeOps:
       def loop(tpe: Type): s.Signature = tpe match {
         case mt: MethodType =>
           val stparams = Some(s.Scope())
-          val sparamss = sym.rawParamss.map(_.sscope)
+          val paramss =
+            if (sym.rawParamss.nonEmpty) sym.rawParamss else sym.paramSymss
+          val sparamss = paramss.map(_.sscope)
           s.MethodSignature(
             stparams,
             sparamss,
@@ -46,7 +49,7 @@ object TypeOps:
             else None
           val sparents = cls.parents.map(_.toSemanticType(sym))
           val sself = cls.selfType.toSemanticType(sym)
-          val decls = cls.decls.toList.sscope(using LinkMode.HardlinkChildren)
+          val decls = cls.decls.toList.sscope
           s.ClassSignature(stparams, sparents, sself, Some(decls))
 
         case TypeBounds(lo, hi) =>
@@ -61,11 +64,15 @@ object TypeOps:
         case pt: PolyType =>
           loop(pt.resType) match {
             case m: s.MethodSignature =>
-              val tparamss = sym.rawParamss.filter(ps => ps.forall(_.isTypeParam))
+              val paramss =
+                if (sym.rawParamss.nonEmpty) sym.rawParamss else sym.paramSymss
+              val tparamss = paramss.filter(ps => ps.forall(_.isTypeParam))
               val stparams = tparamss.flatten.sscope
               m.copy(typeParameters = Some(stparams))
             case v: s.ValueSignature =>
-              val tparamss = sym.rawParamss.filter(ps => ps.forall(_.isTypeParam))
+              val paramss =
+                if (sym.rawParamss.nonEmpty) sym.rawParamss else sym.paramSymss
+              val tparamss = paramss.filter(ps => ps.forall(_.isTypeParam))
               val stparams = tparamss.flatten.sscope
               s.ValueSignature(s.UniversalType(Some(stparams), v.tpe))
             case _ => s.Signature.Empty
@@ -130,7 +137,6 @@ object TypeOps:
 
         case rt @ RefinedType(parent, name, info) =>
           // `X { def x: Int; def y: Int }`
-          //
           // RefinedType(
           //   parent = RefinedType(
           //     parent = TypeRef(..., X)
@@ -139,39 +145,32 @@ object TypeOps:
           //   refinedName = x
           //   refinedInfo = TypeRef(..., Int)
           // )
-
           type RefinedInfo = (core.Names.Name, Type)
           def flatten(tpe: Type, acc: List[RefinedInfo]): (Type, List[RefinedInfo]) = tpe match {
             case RefinedType(parent, name, info) =>
               flatten(parent, acc :+ (name, info))
             case _ =>
               (tpe, acc)
           }
-          val (parent, refinedInfos) = flatten(rt, List.empty)
 
-          val stpe = parent match {
-            // val tp: M with N { def k: Int } = ???
-            case AndType(x, y) =>
-              s.WithType(Seq(loop(x), loop(y))) // TODO: for M with N with L
-            case _ =>
-              s.WithType(Seq(loop(parent)))
+          // flatten parent types to list
+          // e.g. `X with Y with Z { refined }`
+          // RefinedType(parent = AndType(X, AndType(Y, Z)), ...)
+          // => List(X, Y, Z)
+          def flattenParent(parent: Type): List[s.Type] = parent match {
+            case AndType(tp1, tp2) =>
+              flattenParent(tp1) ++ flattenParent(tp2)
+            case _ => List(loop(parent))
           }
-          val decls = for {
+
+          val (parent, refinedInfos) = flatten(rt, List.empty)
+          val stpe = s.WithType(flattenParent(parent))
+
+          // Create dummy symbols for refinements
+          // since there's no way to retrieve symbols of refinements from RefinedType at this moment.
+          val decls = for
             (name, info) <- refinedInfos
-          } yield {
-            // do we need this?
-            // isLegalPrefix returns true outside in typer
-            val pre = ctx.typeAssigner.maybeSkolemizePrefix(rt, name)
-            val denot = rt.findMember(name, pre)
-            // assert(denot.info eq info, s"(${denot.info.show}) is not eq to (${info.show})")
-            println(s"denot.info: ${denot.info}, info: ${info}, sym: ${denot.symbol}")
-            val sym =
-              if denot.symbol.exists then
-                println(s"refined ${denot.symbol.show} with ${info.show}")
-                denot.symbol
-              else ???
-            sym
-          }
+          yield newSymbol(sym, name, EmptyFlags, info)
           val sdecls = decls.sscope(using LinkMode.HardlinkChildren)
           s.StructuralType(stpe, Some(sdecls))