diff --git a/Lib/fontTools/varLib/merger.py b/Lib/fontTools/varLib/merger.py
index 688790c5e..b4b170594 100644
--- a/Lib/fontTools/varLib/merger.py
+++ b/Lib/fontTools/varLib/merger.py
@@ -119,10 +119,10 @@ def merge(merger, self, lst):
assert allNone(lst), (lst)
return
+ lst = [l.classDefs for l in lst]
self.classDefs = {}
# We only care about the .classDefs
self = self.classDefs
- lst = [l.classDefs for l in lst]
allKeys = set()
allKeys.update(*[l.keys() for l in lst])
diff --git a/Tests/varLib/data/master_ttx_interpolatable_ttf/TestFamily-Master0.ttx b/Tests/varLib/data/master_ttx_interpolatable_ttf/TestFamily-Master0.ttx
index f14f89d36..6054e4bdb 100644
--- a/Tests/varLib/data/master_ttx_interpolatable_ttf/TestFamily-Master0.ttx
+++ b/Tests/varLib/data/master_ttx_interpolatable_ttf/TestFamily-Master0.ttx
@@ -517,4 +517,14 @@
+
+
+
+
+
+
+
+
+
+
diff --git a/Tests/varLib/data/master_ttx_interpolatable_ttf/TestFamily-Master1.ttx b/Tests/varLib/data/master_ttx_interpolatable_ttf/TestFamily-Master1.ttx
index 8d5bace5b..afd61de97 100644
--- a/Tests/varLib/data/master_ttx_interpolatable_ttf/TestFamily-Master1.ttx
+++ b/Tests/varLib/data/master_ttx_interpolatable_ttf/TestFamily-Master1.ttx
@@ -517,4 +517,14 @@
+
+
+
+
+
+
+
+
+
+
diff --git a/Tests/varLib/data/master_ttx_interpolatable_ttf/TestFamily-Master2.ttx b/Tests/varLib/data/master_ttx_interpolatable_ttf/TestFamily-Master2.ttx
index 3e20faca6..0ed2f4acd 100644
--- a/Tests/varLib/data/master_ttx_interpolatable_ttf/TestFamily-Master2.ttx
+++ b/Tests/varLib/data/master_ttx_interpolatable_ttf/TestFamily-Master2.ttx
@@ -501,4 +501,14 @@
+
+
+
+
+
+
+
+
+
+
diff --git a/Tests/varLib/data/master_ttx_interpolatable_ttf/TestFamily-Master3.ttx b/Tests/varLib/data/master_ttx_interpolatable_ttf/TestFamily-Master3.ttx
index e1d0375df..5666541e8 100644
--- a/Tests/varLib/data/master_ttx_interpolatable_ttf/TestFamily-Master3.ttx
+++ b/Tests/varLib/data/master_ttx_interpolatable_ttf/TestFamily-Master3.ttx
@@ -501,4 +501,14 @@
+
+
+
+
+
+
+
+
+
+
diff --git a/Tests/varLib/data/master_ttx_interpolatable_ttf/TestFamily-Master4.ttx b/Tests/varLib/data/master_ttx_interpolatable_ttf/TestFamily-Master4.ttx
index c0946fd19..87381873e 100644
--- a/Tests/varLib/data/master_ttx_interpolatable_ttf/TestFamily-Master4.ttx
+++ b/Tests/varLib/data/master_ttx_interpolatable_ttf/TestFamily-Master4.ttx
@@ -501,4 +501,14 @@
+
+
+
+
+
+
+
+
+
+
diff --git a/Tests/varLib/data/test_results/Build.ttx b/Tests/varLib/data/test_results/Build.ttx
index 1bc1880b4..6e9c6e37f 100644
--- a/Tests/varLib/data/test_results/Build.ttx
+++ b/Tests/varLib/data/test_results/Build.ttx
@@ -1,6 +1,16 @@
+
+
+
+
+
+
+
+
+
+
diff --git a/Tests/varLib/data/test_results/BuildMain.ttx b/Tests/varLib/data/test_results/BuildMain.ttx
index 6875c7128..7150a5793 100644
--- a/Tests/varLib/data/test_results/BuildMain.ttx
+++ b/Tests/varLib/data/test_results/BuildMain.ttx
@@ -613,6 +613,16 @@
+
+
+
+
+
+
+
+
+
+
diff --git a/Tests/varLib/data/test_results/InterpolateLayoutMain.ttx b/Tests/varLib/data/test_results/InterpolateLayoutMain.ttx
index 0c0af325b..6a0635d07 100644
--- a/Tests/varLib/data/test_results/InterpolateLayoutMain.ttx
+++ b/Tests/varLib/data/test_results/InterpolateLayoutMain.ttx
@@ -496,4 +496,14 @@
+
+
+
+
+
+
+
+
+
+
diff --git a/Tests/varLib/data/test_results/Mutator.ttx b/Tests/varLib/data/test_results/Mutator.ttx
index fac0997a6..75a0879ec 100644
--- a/Tests/varLib/data/test_results/Mutator.ttx
+++ b/Tests/varLib/data/test_results/Mutator.ttx
@@ -496,4 +496,14 @@
+
+
+
+
+
+
+
+
+
+