diff --git a/tests/err_instance_nop.v.out.2 b/tests/err_instance_nop.v.out.2
new file mode 100644
index 00000000..7a94d24c
--- /dev/null
+++ b/tests/err_instance_nop.v.out.2
@@ -0,0 +1,5 @@
+Toplevel input, characters 0-48:
+> HB.instance Definition _ : M nat := M.Build nat.
+> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Warning: HB: no new instance is generated
+[HB.no-new-instance,HB,elpi,default]
diff --git a/tests/err_miss_dep.v.out.2 b/tests/err_miss_dep.v.out.2
new file mode 100644
index 00000000..493069f1
--- /dev/null
+++ b/tests/err_miss_dep.v.out.2
@@ -0,0 +1,9 @@
+Toplevel input, characters 0-62:
+> HB.structure Definition AbelianGrp := { A of IsAbelianGrp A }.
+> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Warning:
+pulling in dependencies: [err_miss_dep_IsAddComoid] 
+Please list them or end the declaration with '&'
+[HB.implicit-structure-dependency,HB,elpi,default]
+The command has indeed failed with message:
+HB: Unable to find mixin err_miss_dep_IsAddComoid on subject K
diff --git a/tests/missing_join_error.v.out.2 b/tests/missing_join_error.v.out.2
new file mode 100644
index 00000000..0fc8407a
--- /dev/null
+++ b/tests/missing_join_error.v.out.2
@@ -0,0 +1,12 @@
+Toplevel input, characters 0-55:
+> HB.structure Definition B2 :=  {M of isB2 M & isA2 M }.
+> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Warning:
+pulling in dependencies: [missing_join_error_isTop] 
+Please list them or end the declaration with '&'
+[HB.implicit-structure-dependency,HB,elpi,default]
+The command has indeed failed with message:
+You must declare the hierarchy bottom-up or add a missing join. 
+There are two ways out: 
+- declare structure A2B1 before structure B2A1 if B2A1 inherits from it; 
+- declare an additional structure that inherits from both A1 and A2 and from which A2B1 and/or B2A1 inherit.