Merge pull request #5215 from dotty-staging/fix-#5198

Fix #5188: See through annotations and typevars when computing argume…

Author: nicolasstucki

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

@@ -461,7 +461,7 @@ class TypeApplications(val self: Type) extends AnyVal {
    *  otherwise return Nil.
    *  Existential types in arguments are returned as TypeBounds instances.
    */
-  final def argInfos(implicit ctx: Context): List[Type] = self match {
+  final def argInfos(implicit ctx: Context): List[Type] = self.stripTypeVar.stripAnnots match {
     case AppliedType(tycon, args) => args
     case _ => Nil
   }

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

@@ -318,7 +318,10 @@ object Splicer {
 
       case Inlined(EmptyTree, Nil, expansion) => interpretTree(expansion)
 
-      case Typed(SeqLiteral(elems, _), _) =>
+      case Typed(expr, _) =>
+        interpretTree(expr)
+
+      case SeqLiteral(elems, _) =>
         interpretVarargs(elems.map(e => interpretTree(e)))
 
       case _ =>

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

@@ -678,29 +678,39 @@ trait Checking {
     val purityLevel = if (isFinal) Idempotent else Pure
     tree.tpe.widenTermRefExpr match {
       case tp: ConstantType if exprPurity(tree) >= purityLevel => // ok
-      case tp =>
-        def isCaseClassApply(sym: Symbol): Boolean =
-          sym.name == nme.apply && sym.is(Synthetic) && sym.owner.is(Module) && sym.owner.companionClass.is(Case)
-        def isCaseClassNew(sym: Symbol): Boolean =
-          sym.isPrimaryConstructor && sym.owner.is(Case) && sym.owner.isStatic
-        def isCaseObject(sym: Symbol): Boolean = {
-          // TODO add alias to Nil in scala package
-          sym.is(Case) && sym.is(Module)
-        }
-        val allow =
-          ctx.erasedTypes ||
-          ctx.inInlineMethod ||
-          (tree.symbol.isStatic && isCaseObject(tree.symbol) || isCaseClassApply(tree.symbol)) ||
-          isCaseClassNew(tree.symbol)
-        if (!allow) ctx.error(em"$what must be a known value", tree.pos)
-        else {
-          def checkArgs(tree: Tree): Unit = tree match {
-            case Apply(fn, args) =>
-              args.foreach(arg => checkInlineConformant(arg, isFinal, what))
-              checkArgs(fn)
-            case _ =>
-          }
-          checkArgs(tree)
+      case _ =>
+        tree match {
+          case Typed(expr, _) =>
+            checkInlineConformant(expr, isFinal, what)
+          case SeqLiteral(elems, _) =>
+            elems.foreach(elem => checkInlineConformant(elem, isFinal, what))
+          case Apply(fn, List(arg)) if defn.WrapArrayMethods().contains(fn.symbol) =>
+            checkInlineConformant(arg, isFinal, what)
+          case _ =>
+            def isCaseClassApply(sym: Symbol): Boolean =
+              sym.name == nme.apply && sym.is(Synthetic) && sym.owner.is(Module) && sym.owner.companionClass.is(Case)
+            def isCaseClassNew(sym: Symbol): Boolean =
+              sym.isPrimaryConstructor && sym.owner.is(Case) && sym.owner.isStatic
+            def isCaseObject(sym: Symbol): Boolean = {
+              // TODO add alias to Nil in scala package
+              sym.is(Case) && sym.is(Module)
+            }
+            val allow =
+              ctx.erasedTypes ||
+              ctx.inInlineMethod ||
+              (tree.symbol.isStatic && isCaseObject(tree.symbol) || isCaseClassApply(tree.symbol)) ||
+              isCaseClassNew(tree.symbol)
+
+            if (!allow) ctx.error(em"$what must be a known value", tree.pos)
+            else {
+              def checkArgs(tree: Tree): Unit = tree match {
+                case Apply(fn, args) =>
+                  args.foreach(arg => checkInlineConformant(arg, isFinal, what))
+                  checkArgs(fn)
+                case _ =>
+              }
+              checkArgs(tree)
+            }
         }
     }
   }

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

@@ -22,6 +22,7 @@ i4803f
 i4947b
 i5119
 i5119b
+i5188a
 inline-varargs-1
 implicitShortcut
 inline-case-objects

tests/pos/i5188.scala

@@ -0,0 +1,4 @@
+object Test {
+  inline def sum(inline args: Int*): Int = 0
+  sum(1, 2, 3)
+}

tests/run/i5188a.check

@@ -0,0 +1,4 @@
+0
+1
+3
+6

tests/run/i5188a/Macro_1.scala

@@ -0,0 +1,6 @@
+import scala.quoted._
+
+object Lib {
+  inline def sum(inline args: Int*): Int = ~impl(args: _*)
+  def impl(args: Int*): Expr[Int] = args.sum.toExpr
+}

tests/run/i5188a/Test_2.scala

@@ -0,0 +1,9 @@
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    println(Lib.sum())
+    println(Lib.sum(1))
+    println(Lib.sum(1, 2))
+    println(Lib.sum(1, 2, 3))
+  }
+}