T5515 broken in devel2 flavour

The T5515 testcase is broken in the devel2 build flavour:

--- indexed-types/should_fail/T5515.run/T5515.stderr.normalised	2019-01-27 16:01:12.703091135 +0000
+++ indexed-types/should_fail/T5515.run/T5515.comp.stderr.normalised	2019-01-27 16:01:12.703091135 +0000
@@ -1,24 +1,12 @@
+ghc: panic! (the 'impossible' happened)
+  (GHC version 8.7.20190127 for x86_64-unknown-linux):
+	ASSERT failed!
+  rhs axiom D:R:Argf ::
+        Arg f = a_asO[sk:1] -- Defined at T5515.hs:15:8
+  Call stack:
+      CallStack (from HasCallStack):
+        callStackDoc, called at compiler/utils/Outputable.hs:<line>:<column> in <package-id>:Outputable
+        pprPanic, called at compiler/utils/Outputable.hs:<line>:<column> in <package-id>:Outputable
+        assertPprPanic, called at compiler/typecheck/FamInst.hs:<line>:<column> in <package-id>:FamInst
 
-T5515.hs:6:16:
-     Expecting one more argument to ‘ctx’
-      Expected a type, but ‘ctx’ has kind ‘* -> Constraint’
-     In the first argument of ‘Arg’, namely ‘ctx’
-      In the first argument of ‘ctx’, namely ‘(Arg ctx)’
-      In the class declaration for ‘Bome’
-
-T5515.hs:14:1:
-     Type variable ‘a’ is mentioned in the RHS,
-        but not bound on the LHS of the family instance
-     In the type instance declaration for ‘Arg’
-      In the instance declaration for ‘Some f’
-
-T5515.hs:14:10:
-     Could not deduce (C f a0)
-      from the context: C f a
-        bound by an instance declaration:
-                   forall f a. C f a => Some f
-        at T5515.hs:14:10-24
-      The type variable ‘a0’ is ambiguous
-     In the ambiguity check for an instance declaration
-      To defer the ambiguity check to use sites, enable AllowAmbiguousTypes
-      In the instance declaration for ‘Some f’
+Please report this as a GHC bug:  https://www.haskell.org/ghc/reportabug

Trac metadata

Trac field	Value
Version	8.6.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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