Merge pull request #5181 from dotty-staging/add-inline-option

Allow None and Some to be inline parameters

Author: Aggelos Biboudis

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

@@ -111,9 +111,20 @@ object Splicer {
       }
 
     protected def interpretStaticMethodCall(fn: Tree, args: => List[Object])(implicit env: Env): Object = {
-      val (clazz, instance) = loadModule(fn.symbol.owner)
-      val method = getMethod(clazz, fn.symbol.name, paramsSig(fn.symbol))
-      stopIfRuntimeException(method.invoke(instance, args: _*))
+      if (fn.symbol == defn.NoneModuleRef.termSymbol) {
+        // TODO generalize
+        None
+      } else {
+        val (clazz, instance) = loadModule(fn.symbol.owner)
+        val method = getMethod(clazz, fn.symbol.name, paramsSig(fn.symbol))
+        stopIfRuntimeException(method.invoke(instance, args: _*))
+      }
+    }
+
+    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): _*)
+      constr.newInstance(args: _*).asInstanceOf[Object]
     }
 
     protected def unexpectedTree(tree: Tree)(implicit env: Env): Object =
@@ -240,12 +251,13 @@ object Splicer {
 
     def apply(tree: Tree): Boolean = interpretTree(tree)(Map.empty)
 
-    def interpretQuote(tree: tpd.Tree)(implicit env: Env): Boolean = true
-    def interpretTypeQuote(tree: tpd.Tree)(implicit env: Env): Boolean = true
-    def interpretLiteral(value: Any)(implicit env: Env): Boolean = true
-    def interpretVarargs(args: List[Boolean])(implicit env: Env): Boolean = args.forall(identity)
-    def interpretTastyContext()(implicit env: Env): Boolean = true
-    def interpretStaticMethodCall(fn: tpd.Tree, args: => List[Boolean])(implicit env: Env): Boolean = args.forall(identity)
+    protected def interpretQuote(tree: tpd.Tree)(implicit env: Env): Boolean = true
+    protected def interpretTypeQuote(tree: tpd.Tree)(implicit env: Env): Boolean = true
+    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 interpretNew(fn: RefTree, args: => List[Result])(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
@@ -266,6 +278,7 @@ object Splicer {
     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 interpretNew(fn: RefTree, 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 {
@@ -298,7 +311,14 @@ object Splicer {
 
       case Inlined(EmptyTree, Nil, expansion) => interpretTree(expansion)
 
-      case Typed(SeqLiteral(elems, _), _) => interpretVarargs(elems.map(e => interpretTree(e)))
+      case Apply(TypeApply(fun: RefTree, _), args) if fun.symbol.isConstructor && fun.symbol.owner.owner.is(Package) =>
+        interpretNew(fun, args.map(interpretTree))
+
+      case Apply(fun: RefTree, args) if fun.symbol.isConstructor && fun.symbol.owner.owner.is(Package)=>
+        interpretNew(fun, args.map(interpretTree))
+
+      case Typed(SeqLiteral(elems, _), _) =>
+        interpretVarargs(elems.map(e => interpretTree(e)))
 
       case _ =>
         unexpectedTree(tree)

compiler/src/dotty/tools/dotc/typer/Checking.scala

@@ -678,9 +678,22 @@ trait Checking {
     val purityLevel = if (isFinal) Idempotent else Pure
     tree.tpe.widenTermRefExpr match {
       case tp: ConstantType if exprPurity(tree) >= purityLevel => // ok
-      case _ =>
-        val allow = ctx.erasedTypes || ctx.inInlineMethod
+      case tp =>
+        val allow =
+          ctx.erasedTypes ||
+          ctx.inInlineMethod ||
+          // TODO: Make None and Some constant types?
+          tree.symbol.eq(defn.NoneModuleRef.termSymbol) ||
+          tree.symbol.eq(defn.SomeClass.primaryConstructor) ||
+          (tree.symbol.name == nme.apply && tree.symbol.owner == defn.SomeClass.companionModule.moduleClass)
         if (!allow) ctx.error(em"$what must be a constant expression", tree.pos)
+        else tree match {
+          // TODO: add cases for type apply and multiple applies
+          case Apply(_, args) =>
+            for (arg <- args)
+              checkInlineConformant(arg, isFinal, what)
+          case _ =>
+        }
     }
   }
 

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

@@ -24,6 +24,7 @@ i5119
 i5119b
 inline-varargs-1
 implicitShortcut
+inline-option
 lazy-implicit-lists.scala
 lazy-implicit-nums.scala
 lazy-traits.scala

tests/neg/inline-option/Macro_1.scala

@@ -0,0 +1,9 @@
+
+import scala.quoted._
+
+object Macro {
+  def impl(opt: Option[Int]): Expr[Int] = opt match {
+    case Some(i) => i.toExpr
+    case None => '(-1)
+  }
+}

tests/neg/inline-option/Main_2.scala

@@ -0,0 +1,15 @@
+
+object Main {
+  val a: Int = 3
+  size(Some(a)) // error
+
+  val b: Option[Int] = Some(4)
+  size(b) // error
+
+  inline def size(inline opt: Option[Int]): Int = ~Macro.impl(opt)
+
+  inline def size2(inline i: Int): Int = ~Macro.impl(None)
+
+  inline def size3(inline i: Int): Int = ~Macro.impl(Some(i))
+  
+}

tests/run/inline-option.check

@@ -0,0 +1,9 @@
+-1
+1
+2
+-1
+4
+5
+-1
+-1
+6

tests/run/inline-option/Macro_1.scala

@@ -0,0 +1,13 @@
+
+import scala.quoted._
+
+object Macros {
+
+  def impl(opt: Option[Int]): Expr[Int] = opt match {
+    case Some(i) => i.toExpr
+    case None => '(-1)
+  }
+
+  def impl2(opt: Option[Option[Int]]): Expr[Int] = impl(opt.flatten)
+
+}

tests/run/inline-option/Main_2.scala

@@ -0,0 +1,28 @@
+
+object Test {
+
+  def main(args: Array[String]): Unit = {
+    println(size(None))
+    println(size(Some(1)))
+    println(size(new Some(2)))
+
+    println(size2(3))
+    println(size3(4))
+    println(size4(5))
+
+    println(size5(None))
+    println(size5(Some(None)))
+    println(size5(Some(Some(6))))
+  }
+
+  inline def size(inline opt: Option[Int]): Int = ~Macros.impl(opt)
+
+  inline def size2(inline i: Int): Int = ~Macros.impl(None)
+
+  inline def size3(inline i: Int): Int = ~Macros.impl(Some(i))
+
+  inline def size4(inline i: Int): Int = ~Macros.impl2(Some(Some(i)))
+
+  inline def size5(inline opt: Option[Option[Int]]): Int = ~Macros.impl2(opt)
+
+}