Merge pull request #6792 from dotty-staging/fix-macro-splice-checks

Perform full check that a the contents of a macro are valid in PrepareInlineable

Author: nicolasstucki

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

@@ -54,30 +54,14 @@ class PCPCheckAndHeal(@constructorOnly ictx: Context) extends TreeMapWithStages(
    *  - If inside of a macro definition, check the validity of the macro.
    */
   protected def transformSplice(body: Tree, splice: Tree)(implicit ctx: Context): Tree = {
-    if (level >= 1) {
-      val body1 = transform(body)(spliceContext)
-      splice match {
-        case Apply(fun: TypeApply, _) if splice.isTerm =>
-          // Type of the splice itsel must also be healed
-          // internal.Quoted.expr[F[T]](... T ...)  -->  internal.Quoted.expr[F[$t]](... T ...)
-          val tp = checkType(splice.sourcePos).apply(splice.tpe.widenTermRefExpr)
-          cpy.Apply(splice)(cpy.TypeApply(fun)(fun.fun, tpd.TypeTree(tp) :: Nil), body1 :: Nil)
-        case splice: Select => cpy.Select(splice)(body1, splice.name)
-      }
-    }
-    else {
-      assert(enclosingInlineds.isEmpty, "unexpanded macro")
-      assert(ctx.owner.isInlineMethod)
-      if (Splicer.canBeSpliced(body)) { // level 0 inside an inline definition
-        transform(body)(spliceContext) // Just check PCP
-        splice
-      }
-      else { // level 0 inside an inline definition
-        ctx.error(
-          "Malformed macro call. The contents of the splice ${...} must call a static method and arguments must be quoted or inline.",
-          splice.sourcePos)
-        splice
-      }
+    val body1 = transform(body)(spliceContext)
+    splice match {
+      case Apply(fun: TypeApply, _) if splice.isTerm =>
+        // Type of the splice itsel must also be healed
+        // internal.Quoted.expr[F[T]](... T ...)  -->  internal.Quoted.expr[F[$t]](... T ...)
+        val tp = checkType(splice.sourcePos).apply(splice.tpe.widenTermRefExpr)
+        cpy.Apply(splice)(cpy.TypeApply(fun)(fun.fun, tpd.TypeTree(tp) :: Nil), body1 :: Nil)
+      case splice: Select => cpy.Select(splice)(body1, splice.name)
     }
   }
 

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

@@ -251,9 +251,14 @@ object PrepareInlineable {
        */
       object InlineSplice {
         def unapply(tree: Tree)(implicit ctx: Context): Option[Tree] = tree match {
-          case Spliced(code) if Splicer.canBeSpliced(code) =>
-            if (code.symbol.flags.is(Inline))
+          case Spliced(code) =>
+            if (!Splicer.canBeSpliced(code)) {
+              ctx.error(
+                "Malformed macro call. The contents of the splice ${...} must call a static method and arguments must be quoted or inline.",
+                tree.sourcePos)
+            } else if (code.symbol.flags.is(Inline)) {
               ctx.error("Macro cannot be implemented with an `inline` method", code.sourcePos)
+            }
             Some(code)
           case Block(List(stat), Literal(Constants.Constant(()))) => unapply(stat)
           case Block(Nil, expr) => unapply(expr)

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

@@ -2263,7 +2263,7 @@ class Typer extends Namer
       ctx.error("Splice ${...} outside quotes '{...} or inline method", tree.sourcePos)
     else if (level < 0)
       ctx.error(
-        """Splice ${...} at level -1.
+        s"""Splice $${...} at level $level.
           |
           |Inline method may contain a splice at level 0 but the contents of this splice cannot have a splice.
           |""".stripMargin, tree.sourcePos