Improve exception message for aliased bundle fields (#2304)

- Shows groups of field names that share a common id (i.e. aliased)
- Show, as much as possible, them in the order that fields appear in bundle
- Updated BundleSpec's relevant tests

Co-authored-by: Megan Wachs <megan@sifive.com>
Co-authored-by: Jack Koenig <koenig@sifive.com>

1 files changed, 10 insertions, 6 deletions

diff --git a/src/test/scala/chiselTests/BundleSpec.scala b/src/test/scala/chiselTests/BundleSpec.scala
index 51dedfb1..d9f82e6d 100644
--- a/src/test/scala/chiselTests/BundleSpec.scala
+++ b/src/test/scala/chiselTests/BundleSpec.scala
@@ -111,17 +111,21 @@ class BundleSpec extends ChiselFlatSpec with BundleSpecUtils with Utils {
     }
   }
 
-  "Bundles" should "not have aliased fields" in {
+  "Bundles" should "with aliased fields, should show a helpful error message" in {
+    class AliasedBundle extends Bundle {
+      val a = UInt(8.W)
+      val b = a
+      val c = SInt(8.W)
+      val d = c
+    }
+
     (the[ChiselException] thrownBy extractCause[ChiselException] {
       ChiselStage.elaborate { new Module {
-        val io = IO(Output(new Bundle {
-          val a = UInt(8.W)
-          val b = a
-        }))
+        val io = IO(Output(new AliasedBundle))
         io.a := 0.U
         io.b := 1.U
       } }
-    }).getMessage should include("aliased fields")
+    }).getMessage should include("contains aliased fields named (a,b),(c,d)")
   }
 
   "Bundles" should "not have bound hardware" in {