Merge pull request #12893 from dotty-staging/fix-reflect-members

Properly handle self-types in reflection member lookup

Author: nicolasstucki

compiler/src/scala/quoted/runtime/impl/QuotesImpl.scala

@@ -2483,15 +2483,22 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
 
         def declaredFields: List[Symbol] = self.unforcedDecls.filter(isField)
 
+        /** The prefix on which a member lookup should be performed. */
+        private def lookupPrefix: TypeRepr =
+          if self.isClass then
+            self.thisType // Needed to handle self-types (as in tests/run-macros/self)
+          else
+            self.namedType
+
         def memberField(name: String): Symbol = fieldMember(name)
         def fieldMember(name: String): Symbol =
-          appliedTypeRef(self).allMembers.iterator.map(_.symbol).find {
+          lookupPrefix.allMembers.iterator.map(_.symbol).find {
             sym => isField(sym) && sym.name.toString == name
           }.getOrElse(dotc.core.Symbols.NoSymbol)
 
         def memberFields: List[Symbol] = fieldMembers
         def fieldMembers: List[Symbol] =
-          appliedTypeRef(self).allMembers.iterator.map(_.symbol).collect {
+          lookupPrefix.allMembers.iterator.map(_.symbol).collect {
             case sym if isField(sym) => sym.asTerm
           }.toList
 
@@ -2507,13 +2514,13 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
 
         def memberMethod(name: String): List[Symbol] = methodMember(name)
         def methodMember(name: String): List[Symbol] =
-          appliedTypeRef(self).allMembers.iterator.map(_.symbol).collect {
+          lookupPrefix.allMembers.iterator.map(_.symbol).collect {
             case sym if isMethod(sym) && sym.name.toString == name => sym.asTerm
           }.toList
 
         def memberMethods: List[Symbol] = methodMembers
         def methodMembers: List[Symbol] =
-          appliedTypeRef(self).allMembers.iterator.map(_.symbol).collect {
+          lookupPrefix.allMembers.iterator.map(_.symbol).collect {
             case sym if isMethod(sym) => sym.asTerm
           }.toList
 

scaladoc/src/dotty/tools/scaladoc/tasty/SyntheticSupport.scala

@@ -74,7 +74,13 @@ object SyntheticsSupport:
     import dotty.tools.dotc
     given ctx: dotc.core.Contexts.Context = quotes.asInstanceOf[scala.quoted.runtime.impl.QuotesImpl].ctx
     val sym = rsym.asInstanceOf[dotc.core.Symbols.Symbol]
-    sym.typeRef.appliedTo(sym.typeParams.map(_.typeRef)).allMembers.iterator.map(_.symbol)
+    // `lookupPrefix` is private in `QuotesImpl#SymbolMethods`
+    val lookupPrefix =
+      if sym.isClass then
+        sym.thisType
+      else
+        sym.namedType
+    lookupPrefix.allMembers.iterator.map(_.symbol)
       .collect {
          case sym if
           (!sym.is(dotc.core.Flags.ModuleVal) || sym.is(dotc.core.Flags.Given)) &&

tests/run-macros/self.check

@@ -0,0 +1,3 @@
+ExprType(TypeRef(TermRef(ThisType(TypeRef(NoPrefix,module class <root>)),object scala),Int))
+MethodType(List(x), List(TypeRef(TermRef(TermRef(ThisType(TypeRef(NoPrefix,module class <root>)),object scala),Predef),String)), TypeRef(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,module class <root>)),module class <empty>)),B),X))
+MethodType(List(x), List(TypeRef(TermRef(ThisType(TypeRef(NoPrefix,module class <root>)),object scala),Int)), TypeRef(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,module class <root>)),module class <empty>)),B),X))

tests/run-macros/self/Macro_1.scala

@@ -0,0 +1,35 @@
+import scala.quoted.*
+
+trait A {
+  type X
+}
+trait B { self: A =>
+  def foo(x: Int): X
+  def foo(x: String): X
+}
+
+object Obj {
+  def foo: Int = 1
+}
+
+object Macros {
+
+  inline def test(): String = ${ testImpl }
+
+  private def testImpl(using Quotes) : Expr[String] = {
+    import quotes.reflect.*
+    val bTpe = TypeRepr.of[B]
+    val bSym = bTpe.classSymbol.get
+    val bMethSyms = bSym.methodMember("foo") // Used to throw a MissingType exception
+    val bMethTpes = bMethSyms.map(bTpe.memberType)
+
+    // Make sure we didn't break member lookup on terms
+    val objTpe = TypeRepr.of[Obj.type]
+    val objSym = objTpe.termSymbol
+    val objMethSyms = objSym.methodMember("foo")
+    val objMethTpes = objMethSyms.map(objTpe.memberType)
+
+    Expr((objMethTpes ++ bMethTpes).map(_.toString).sorted.mkString("\n"))
+  }
+
+}

tests/run-macros/self/Test_2.scala

@@ -0,0 +1,8 @@
+
+object Test {
+
+  def main(args: Array[String]): Unit = {
+    println(Macros.test())
+  }
+
+}