Promoted bug file to ci, added explanation

test/ci/front-end/inst_mod_frac_field.rav

@@ -0,0 +1,34 @@
+interface A[Tp: Library.Type] {
+    field f: Tp.T
+}
+
+interface M {
+   module RefType : Library.Type {
+    rep type T = Ref
+  }
+
+  interface AN = A[RefType]
+
+  proc p(x: Ref) {
+    inhale own(x, AN.f, x, 1.0);
+  }
+
+  /*
+    There is a bug in the `rewrite_own_expr_4_arg` rewriter which 
+    translates 4-arg own chunks into uniform 3-arg own chunks.
+
+    The name for the Frac module generated to rewrite the inhale expression is:
+      $Program.M.AN.Frac$Fld-Ref-.T
+
+    The name that is actually generated during the `rewrite_frac_field_types` rewrite is:
+      $Program.A.Frac$Fld-$Program_A_Tp_T-.T
+  */
+
+
+  /*
+    This bug was fixed in the following commit:
+      b0f5e2d7a172fe321c677dcbad14eb340563097b
+
+    Earlier, `rewrite_frac_field_types` was using field types to generate frac module name. Switched to using field_name.
+  */
+}

test/ci/front-end/inst_mod_frac_field.t

@@ -0,0 +1,2 @@
+  $ dune exec -- raven --shh ./inst_mod_frac_field.rav
+  Verification successful.