Can't find interface-file decl with Typeable

The attached code produces the following error:

GHC error in desugarer lookup in Main:
  Can't find interface-file declaration for variable $tc'(,)
    Probable cause: bug in .hi-boot file, or inconsistent .hi file
    Use -ddump-if-trace to get an idea of which file caused the error
ghc: panic! (the 'impossible' happened)
  (GHC version 8.0.1 for x86_64-unknown-linux):
        initDs IOEnv failure

when I run stack bench lol. The issue seems to be related to Typeable instances for types created with singletons.

Trac metadata

Trac field	Value
Version	8.0.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
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Related
Blocking
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changed weight to 5

added Tbug Trac import labels

Attached file bug.tar.gz (download).

If anyone can offer an easy way to reproduce this, it'd be great.

Simon

closed

changed milestone to %8.0.2

This is really #12132 (closed) in disguise (which has been fixed in GHC 8.0.2 and HEAD). You can see this by observing the output of compiling Main with -ddump-splices:

[3 of 3] Compiling Main             ( Main.hs, interpreted )
Main.hs:7:3-26: Splicing declarations
    sequence [ppDec $ (2, 1)]
  ======>
    type PP2 = PP '(P (PosBin.D0 PosBin.B1), PosBin.O)

The key part is that PP2 contains a promoted boxed tuple, and the error happens when you try to get the Typeable instance for it.

In any case, this has already been fixed, and it'd be impractical to create a regression test from all of this singletons code, so I'll just close this as a duplicate.

Trac metadata

Trac field	Value
Resolution	Unresolved → ResolvedDuplicate
Related	- → #12132 (closed)

added compiler crash label

added Pnormal label