Broken auto-clonetype on Scala 2.11.12 (#1480)

* Added broken auto-clonetype test

* Added bugfix for 2.11

* Add descriptive comment for 2.11 special case

* Update src/test/scala/chiselTests/AutoClonetypeSpec.scala

* Update src/test/scala/chiselTests/AutoClonetypeSpec.scala

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

2 files changed, 36 insertions, 1 deletions

diff --git a/core/src/main/scala/chisel3/Aggregate.scala b/core/src/main/scala/chisel3/Aggregate.scala
index 523d404d..4e9a95c1 100644
--- a/core/src/main/scala/chisel3/Aggregate.scala
+++ b/core/src/main/scala/chisel3/Aggregate.scala
@@ -824,7 +824,20 @@ abstract class Bundle(implicit compileOptions: CompileOptions) extends Record {
       }
     }
 
+    val isAnonFunc = ".*\\$\\$anonfun\\$\\d+$".r
+    // In Scala 2.11, anonymous functions were compiled to their own classes, while in Scala 2.12,
+    // they are directly compiled into the enclosing classes. This meant that checking the enclosing
+    // parent in 2.12 would work, but in 2.11 they wouldn't. This fix just looks for the first enclosing class
+    // which is not an anonymous function.
+    def getNonFuncClass(clz: Class[_]): Option[Class[_]] = {
+      clz.getName match {
+        case isAnonFunc() => getNonFuncClass(clz.getEnclosingClass)
+        case _ => Some(clz)
+      }
+    }
+
     val mirror = runtimeMirror(clazz.getClassLoader)
+
     val classSymbolOption = try {
       Some(mirror.reflect(this).symbol)
     } catch {
@@ -834,7 +847,7 @@ abstract class Bundle(implicit compileOptions: CompileOptions) extends Record {
     val enclosingClassOption = (clazz.getEnclosingClass, classSymbolOption) match {
       case (null, _) => None
       case (_, Some(classSymbol)) if classSymbol.isStatic => None  // allows support for members of companion objects
-      case (outerClass, _) => Some(outerClass)
+      case (parent, _) => getNonFuncClass(parent)
     }
 
     // For compatibility with pre-3.1, where null is tried as an argument to the constructor.
diff --git a/src/test/scala/chiselTests/AutoClonetypeSpec.scala b/src/test/scala/chiselTests/AutoClonetypeSpec.scala
index 88f6378b..d5607dc1 100644
--- a/src/test/scala/chiselTests/AutoClonetypeSpec.scala
+++ b/src/test/scala/chiselTests/AutoClonetypeSpec.scala
@@ -196,4 +196,26 @@ class AutoClonetypeSpec extends ChiselFlatSpec with Utils {
       } }
     }
   }
+
+  "Wrapped IO construction without parent reference" should "not fail for autoclonetype" in {
+    class TestModule extends MultiIOModule {
+      def thunk[T](f: => T): T = f
+      val works = thunk(IO(new Bundle {
+        val x = Output(UInt(3.W))
+      }))
+    }
+    ChiselStage.elaborate { new TestModule }
+  }
+
+  "Wrapped IO construction with parent references" should "not fail for autoclonetype" in {
+    class TestModule(blah: Int) extends MultiIOModule {
+      // Note that this currently fails only if f: =>T on Scala 2.11.12
+      // This works successfully with 2.12.11
+      def thunk[T](f: => T): T = f
+      val broken = thunk(IO(new Bundle {
+        val x = Output(UInt(blah.W))
+      }))
+    }
+    ChiselStage.elaborate { new TestModule(3) }
+  }
 }