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| -rw-r--r-- | compiler/typecheck/FamInst.hs | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/compiler/typecheck/FamInst.hs b/compiler/typecheck/FamInst.hs index 0229c84416..b6b85b187f 100644 --- a/compiler/typecheck/FamInst.hs +++ b/compiler/typecheck/FamInst.hs @@ -127,6 +127,13 @@ module. Otherwise, we'll end up with no record of the fact that M depends on this family instance and type safety will be compromised. See #13102. +* It can also happen that M uses a function defined in another module +which is not transitively imported by M. Examples include the +desugaring of various overloaded constructs, and references inserted +by Template Haskell splices. If that function's definition makes use +of type family instances which are not checked against those visible +visible from M, type safety can again be compromised. See #13251. + * When a module C imports a boot module B.hs-boot, we check that C's type family instances are compatible with those visible from B.hs-boot. However, C will eventually be linked against a different |