Fix #8945: Support macro bundles

nicolasstucki · nicolasstucki · commit b76d01d077dd · 2020-05-12T17:53:39.000+02:00
diff --git a/compiler/src/dotty/tools/dotc/typer/Typer.scala b/compiler/src/dotty/tools/dotc/typer/Typer.scala
@@ -3446,15 +3446,31 @@ class Typer extends Namer
   /** Types the body Scala 2 macro declaration `def f = macro <body>` */
   private def typedScala2MacroBody(call: untpd.Tree)(using Context): Tree =
     // TODO check that call is to a method with valid signature
-    call match
-      case rhs0: untpd.Ident =>
-        typedIdent(rhs0, defn.AnyType)
-      case rhs0: untpd.Select =>
-        typedSelect(rhs0, defn.AnyType)
-      case rhs0: untpd.TypeApply =>
-        typedTypeApply(rhs0, defn.AnyType)
-      case _ =>
-        ctx.error("Invalid Scala 2 macro", call.sourcePos)
-        EmptyTree
+    def typedPrefix(tree: untpd.RefTree): Tree = {
+      tryAlternatively {
+        typedExpr(tree, defn.AnyType)
+      } {
+        // Try to type as a macro bundle
+        val ref = tree match
+          case Ident(name) => untpd.Ident(name.toTypeName).withSpan(tree.span)
+          case Select(qual, name) => untpd.Select(qual, name.toTypeName).withSpan(tree.span)
+        val bundle = untpd.Apply(untpd.Select(untpd.New(ref), nme.CONSTRUCTOR), untpd.Literal(Constant(null))).withSpan(call.span)
+        typedExpr(bundle, defn.AnyType)
+      }
+    }
+    if ctx.phase.isTyper then
+      call match
+        case call: untpd.Ident =>
+          typedIdent(call, defn.AnyType)
+        case untpd.Select(qual: untpd.RefTree, name) =>
+          val call2 = untpd.Select(untpd.TypedSplice(typedPrefix(qual)), name).withSpan(call.span)
+          typedSelect(call2, defn.AnyType)
+        case untpd.TypeApply(untpd.Select(qual: untpd.RefTree, name), targs) =>
+          val call2= untpd.TypeApply(untpd.Select(untpd.TypedSplice(typedPrefix(qual)), name), targs).withSpan(call.span)
+          typedTypeApply(call2, defn.AnyType)
+        case _ =>
+          ctx.error("Invalid Scala 2 macro " + call.show, call.sourcePos)
+          EmptyTree
+    else typedExpr(call, defn.AnyType)
 
 }
diff --git a/tests/pos/i8945.scala b/tests/pos/i8945.scala
@@ -0,0 +1,27 @@
+// src-2/MacroImpl.scala
+trait Context {
+  object universe {
+    type Literal
+  }
+}
+
+class MacroImpl(val c: Context) {
+  import c.universe._
+  def mono: Literal = ???
+}
+
+// src-3/Macros.scala
+import scala.language.experimental.macros
+
+object Macros {
+
+  object Bundles {
+    def mono: Unit = macro MacroImpl.mono
+    inline def mono: Unit = ${ Macros3.monoImpl }
+  }
+
+  object Macros3 {
+    def monoImpl(using quoted.QuoteContext) = '{()}
+  }
+
+}
