Merge pull request #5299 from dotty-staging/fix-macro-with-implicit-fun-type

Allow macros to call method returning implicit functions

Author: nicolasstucki

compiler/src/dotty/tools/dotc/transform/Splicer.scala

@@ -10,12 +10,13 @@ import dotty.tools.dotc.core.Contexts._
 import dotty.tools.dotc.core.Decorators._
 import dotty.tools.dotc.core.Flags._
 import dotty.tools.dotc.core.NameKinds.FlatName
-import dotty.tools.dotc.core.Names.Name
+import dotty.tools.dotc.core.Names.{Name, TermName}
+import dotty.tools.dotc.core.StdNames.nme
 import dotty.tools.dotc.core.StdNames.str.MODULE_INSTANCE_FIELD
 import dotty.tools.dotc.core.quoted._
 import dotty.tools.dotc.core.Types._
 import dotty.tools.dotc.core.Symbols._
-import dotty.tools.dotc.core.TypeErasure
+import dotty.tools.dotc.core.{NameKinds, TypeErasure}
 import dotty.tools.dotc.core.Constants.Constant
 import dotty.tools.dotc.tastyreflect.TastyImpl
 
@@ -105,23 +106,30 @@ object Splicer {
     protected def interpretVarargs(args: List[Object])(implicit env: Env): Object =
       args.toSeq
 
-    protected def interpretTastyContext()(implicit env: Env): Object =
+    protected def interpretTastyContext()(implicit env: Env): Object = {
       new TastyImpl(ctx) {
         override def rootPosition: SourcePosition = pos
       }
+    }
 
-    protected def interpretStaticMethodCall(fn: Tree, args: => List[Object])(implicit env: Env): Object = {
-      val instance = loadModule(fn.symbol.owner)
-      val method = getMethod(instance.getClass, fn.symbol.name, paramsSig(fn.symbol))
+    protected def interpretStaticMethodCall(fn: Symbol, args: => List[Object])(implicit env: Env): Object = {
+      val instance = loadModule(fn.owner)
+      def getDirectName(tp: Type, name: TermName): TermName = tp.widenDealias match {
+        case tp: AppliedType if defn.isImplicitFunctionType(tp) =>
+          getDirectName(tp.args.last, NameKinds.DirectMethodName(name))
+        case _ => name
+      }
+      val name = getDirectName(fn.info.finalResultType, fn.name.asTermName)
+      val method = getMethod(instance.getClass, name, paramsSig(fn))
       stopIfRuntimeException(method.invoke(instance, args: _*))
     }
 
-    protected def interpretModuleAccess(fn: Tree)(implicit env: Env): Object =
-      loadModule(fn.symbol.moduleClass)
+    protected def interpretModuleAccess(fn: Symbol)(implicit env: Env): Object =
+      loadModule(fn.moduleClass)
 
-    protected def interpretNew(fn: RefTree, args: => List[Result])(implicit env: Env): Object = {
-      val clazz = loadClass(fn.symbol.owner.fullName)
-      val constr = clazz.getConstructor(paramsSig(fn.symbol): _*)
+    protected def interpretNew(fn: Symbol, args: => List[Result])(implicit env: Env): Object = {
+      val clazz = loadClass(fn.owner.fullName)
+      val constr = clazz.getConstructor(paramsSig(fn): _*)
       constr.newInstance(args: _*).asInstanceOf[Object]
     }
 
@@ -190,50 +198,58 @@ object Splicer {
 
     /** List of classes of the parameters of the signature of `sym` */
     private def paramsSig(sym: Symbol): List[Class[_]] = {
-      TypeErasure.erasure(sym.info) match {
-        case meth: MethodType =>
-          meth.paramInfos.map { param =>
-            def arrayDepth(tpe: Type, depth: Int): (Type, Int) = tpe match {
-              case JavaArrayType(elemType) => arrayDepth(elemType, depth + 1)
-              case _ => (tpe, depth)
-            }
-            def javaArraySig(tpe: Type): String = {
-              val (elemType, depth) = arrayDepth(tpe, 0)
-              val sym = elemType.classSymbol
-              val suffix =
-                if (sym == defn.BooleanClass) "Z"
-                else if (sym == defn.ByteClass) "B"
-                else if (sym == defn.ShortClass) "S"
-                else if (sym == defn.IntClass) "I"
-                else if (sym == defn.LongClass) "J"
-                else if (sym == defn.FloatClass) "F"
-                else if (sym == defn.DoubleClass) "D"
-                else if (sym == defn.CharClass) "C"
-                else "L" + javaSig(elemType) + ";"
-              ("[" * depth) + suffix
-            }
-            def javaSig(tpe: Type): String = tpe match {
-              case tpe: JavaArrayType => javaArraySig(tpe)
-              case _ =>
-                // Take the flatten name of the class and the full package name
-                val pack = tpe.classSymbol.topLevelClass.owner
-                val packageName = if (pack == defn.EmptyPackageClass) "" else pack.fullName + "."
-                packageName + tpe.classSymbol.fullNameSeparated(FlatName).toString
-            }
-
-            val sym = param.classSymbol
-            if (sym == defn.BooleanClass) classOf[Boolean]
-            else if (sym == defn.ByteClass) classOf[Byte]
-            else if (sym == defn.CharClass) classOf[Char]
-            else if (sym == defn.ShortClass) classOf[Short]
-            else if (sym == defn.IntClass) classOf[Int]
-            else if (sym == defn.LongClass) classOf[Long]
-            else if (sym == defn.FloatClass) classOf[Float]
-            else if (sym == defn.DoubleClass) classOf[Double]
-            else java.lang.Class.forName(javaSig(param), false, classLoader)
-          }
+      def paramClass(param: Type): Class[_] = {
+        def arrayDepth(tpe: Type, depth: Int): (Type, Int) = tpe match {
+          case JavaArrayType(elemType) => arrayDepth(elemType, depth + 1)
+          case _ => (tpe, depth)
+        }
+        def javaArraySig(tpe: Type): String = {
+          val (elemType, depth) = arrayDepth(tpe, 0)
+          val sym = elemType.classSymbol
+          val suffix =
+            if (sym == defn.BooleanClass) "Z"
+            else if (sym == defn.ByteClass) "B"
+            else if (sym == defn.ShortClass) "S"
+            else if (sym == defn.IntClass) "I"
+            else if (sym == defn.LongClass) "J"
+            else if (sym == defn.FloatClass) "F"
+            else if (sym == defn.DoubleClass) "D"
+            else if (sym == defn.CharClass) "C"
+            else "L" + javaSig(elemType) + ";"
+          ("[" * depth) + suffix
+        }
+        def javaSig(tpe: Type): String = tpe match {
+          case tpe: JavaArrayType => javaArraySig(tpe)
+          case _ =>
+            // Take the flatten name of the class and the full package name
+            val pack = tpe.classSymbol.topLevelClass.owner
+            val packageName = if (pack == defn.EmptyPackageClass) "" else pack.fullName + "."
+            packageName + tpe.classSymbol.fullNameSeparated(FlatName).toString
+        }
+
+        val sym = param.classSymbol
+        if (sym == defn.BooleanClass) classOf[Boolean]
+        else if (sym == defn.ByteClass) classOf[Byte]
+        else if (sym == defn.CharClass) classOf[Char]
+        else if (sym == defn.ShortClass) classOf[Short]
+        else if (sym == defn.IntClass) classOf[Int]
+        else if (sym == defn.LongClass) classOf[Long]
+        else if (sym == defn.FloatClass) classOf[Float]
+        else if (sym == defn.DoubleClass) classOf[Double]
+        else java.lang.Class.forName(javaSig(param), false, classLoader)
+      }
+      def getExtraParams(tp: Type): List[Type] = tp.widenDealias match {
+        case tp: AppliedType if defn.isImplicitFunctionType(tp) =>
+          // Call implicit function type direct method
+          tp.args.init.map(arg => TypeErasure.erasure(arg)) ::: getExtraParams(tp.args.last)
         case _ => Nil
       }
+      val extraParams = getExtraParams(sym.info.finalResultType)
+      val allParams = TypeErasure.erasure(sym.info) match {
+        case meth: MethodType => meth.paramInfos ::: extraParams
+        case _ => extraParams
+      }
+      allParams.map(paramClass)
     }
 
     /** Exception that stops interpretation if some issue is found */
@@ -253,9 +269,10 @@ object Splicer {
     protected def interpretLiteral(value: Any)(implicit env: Env): Boolean = true
     protected def interpretVarargs(args: List[Boolean])(implicit env: Env): Boolean = args.forall(identity)
     protected def interpretTastyContext()(implicit env: Env): Boolean = true
-    protected def interpretStaticMethodCall(fn: tpd.Tree, args: => List[Boolean])(implicit env: Env): Boolean = args.forall(identity)
-    protected def interpretModuleAccess(fn: Tree)(implicit env: Env): Boolean = true
-    protected def interpretNew(fn: RefTree, args: => List[Boolean])(implicit env: Env): Boolean = args.forall(identity)
+    protected def interpretQuoteContext()(implicit env: Env): Boolean = true
+    protected def interpretStaticMethodCall(fn: Symbol, args: => List[Boolean])(implicit env: Env): Boolean = args.forall(identity)
+    protected def interpretModuleAccess(fn: Symbol)(implicit env: Env): Boolean = true
+    protected def interpretNew(fn: Symbol, args: => List[Boolean])(implicit env: Env): Boolean = args.forall(identity)
 
     def unexpectedTree(tree: tpd.Tree)(implicit env: Env): Boolean = {
       // Assuming that top-level splices can only be in inline methods
@@ -275,9 +292,9 @@ object Splicer {
     protected def interpretLiteral(value: Any)(implicit env: Env): Result
     protected def interpretVarargs(args: List[Result])(implicit env: Env): Result
     protected def interpretTastyContext()(implicit env: Env): Result
-    protected def interpretStaticMethodCall(fn: Tree, args: => List[Result])(implicit env: Env): Result
-    protected def interpretModuleAccess(fn: Tree)(implicit env: Env): Result
-    protected def interpretNew(fn: RefTree, args: => List[Result])(implicit env: Env): Result
+    protected def interpretStaticMethodCall(fn: Symbol, args: => List[Result])(implicit env: Env): Result
+    protected def interpretModuleAccess(fn: Symbol)(implicit env: Env): Result
+    protected def interpretNew(fn: Symbol, args: => List[Result])(implicit env: Env): Result
     protected def unexpectedTree(tree: Tree)(implicit env: Env): Result
 
     protected final def interpretTree(tree: Tree)(implicit env: Env): Result = tree match {
@@ -295,10 +312,10 @@ object Splicer {
 
       case Call(fn, args) =>
         if (fn.symbol.isConstructor && fn.symbol.owner.owner.is(Package)) {
-          interpretNew(fn, args.map(interpretTree))
+          interpretNew(fn.symbol, args.map(interpretTree))
         } else if (fn.symbol.isStatic) {
-          if (fn.symbol.is(Module)) interpretModuleAccess(fn)
-          else interpretStaticMethodCall(fn, args.map(arg => interpretTree(arg)))
+          if (fn.symbol.is(Module)) interpretModuleAccess(fn.symbol)
+          else interpretStaticMethodCall(fn.symbol, args.map(arg => interpretTree(arg)))
         } else if (env.contains(fn.name)) {
           env(fn.name)
         } else {
@@ -330,6 +347,8 @@ object Splicer {
 
     object Call {
       def unapply(arg: Tree): Option[(RefTree, List[Tree])] = arg match {
+        case Select(Call(fn, args), nme.apply) if defn.isImplicitFunctionType(fn.tpe.widenDealias.finalResultType) =>
+          Some((fn, args))
         case fn: RefTree => Some((fn, Nil))
         case Apply(Call(fn, args1), args2) => Some((fn, args1 ::: args2)) // TODO improve performance
         case TypeApply(Call(fn, args), _) => Some((fn, args))

compiler/test/dotc/run-test-pickling.blacklist

@@ -72,7 +72,9 @@ tasty-extractors-constants-1
 tasty-extractors-owners
 tasty-extractors-types
 tasty-getfile
+tasty-getfile-implicit-fun-context
 tasty-indexed-map
+tasty-implicit-fun-context-2
 tasty-linenumber
 tasty-linenumber-2
 tasty-location

tests/run/tasty-getfile-implicit-fun-context.check

@@ -0,0 +1 @@
+App_2.scala

tests/run/tasty-getfile-implicit-fun-context/App_2.scala

@@ -0,0 +1,6 @@
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    println(SourceFiles.getThisFile)
+  }
+}

tests/run/tasty-getfile-implicit-fun-context/Macro_1.scala

@@ -0,0 +1,19 @@
+import scala.quoted._
+import scala.tasty.Tasty
+
+object SourceFiles {
+
+  type Macro[X] = implicit Tasty => Expr[X]
+  def tastyContext(implicit ctx: Tasty): Tasty = ctx
+
+  implicit inline def getThisFile: String =
+    ~getThisFileImpl
+
+  def getThisFileImpl: Macro[String] = {
+    val tasty = tastyContext
+    import tasty._
+    rootContext.source.getFileName.toString.toExpr
+  }
+
+
+}

tests/run/tasty-implicit-fun-context-2.check

@@ -0,0 +1 @@
+abc

tests/run/tasty-implicit-fun-context-2/App_2.scala

@@ -0,0 +1,6 @@
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    println(Foo.foo)
+  }
+}

tests/run/tasty-implicit-fun-context-2/Macro_1.scala

@@ -0,0 +1,16 @@
+import scala.quoted._
+import scala.tasty.Tasty
+
+object Foo {
+
+  type Macro[X] = implicit Tasty => Expr[X]
+  type Tastier[X] = implicit Tasty => X
+
+  implicit inline def foo: String =
+    ~fooImpl
+
+  def fooImpl(implicit tasty: Tasty): implicit Tasty => Tastier[implicit Tasty => Macro[String]] = {
+    '("abc")
+  }
+
+}