When we resolve an undfined name we record error, but we continue
processing things, so that we can report multiple errors.  As a result
we need to generate some sort of fake "real" name for the undefined entity.

Previously we used to generate a fake local name, but that confused parts
of the code that expected certain things to always be defined at the top
level.  So now we generate a fake name in the Cryptol prelude instead.

Fixes #1363

Fixes #1385

Also, for the names of the imported instances now
use the location in the file to make them unique,
rather than a synthetic counter,

Still to do: modules and funcotrs

I am not sure that the parser can actually parse these,
but if we add them, this should just work

# Conflicts:
#	docs/RefMan/Modules.rst
#	docs/RefMan/_build/doctrees/BasicSyntax.doctree
#	docs/RefMan/_build/doctrees/BasicTypes.doctree
#	docs/RefMan/_build/doctrees/Expressions.doctree
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#	docs/RefMan/_build/doctrees/environment.pickle
#	docs/RefMan/_build/html/Modules.html
#	docs/RefMan/_build/html/_sources/Modules.rst.txt
#	docs/RefMan/_build/html/searchindex.js

# Conflicts:
#	cryptol-remote-api/src/CryptolServer/Exceptions.hs
#	cryptol.cabal
#	docs/RefMan/_build/doctrees/BasicSyntax.doctree
#	docs/RefMan/_build/doctrees/BasicTypes.doctree
#	docs/RefMan/_build/doctrees/Expressions.doctree
#	docs/RefMan/_build/doctrees/Modules.doctree
#	docs/RefMan/_build/doctrees/OverloadedOperations.doctree
#	docs/RefMan/_build/doctrees/RefMan.doctree
#	docs/RefMan/_build/doctrees/TypeDeclarations.doctree
#	docs/RefMan/_build/doctrees/environment.pickle
#	docs/RefMan/_build/html/Modules.html
#	docs/RefMan/_build/html/searchindex.js
#	src/Cryptol/ModuleSystem.hs
#	src/Cryptol/ModuleSystem/Base.hs
#	src/Cryptol/ModuleSystem/Env.hs
#	src/Cryptol/ModuleSystem/InstantiateModule.hs
#	src/Cryptol/ModuleSystem/Monad.hs
#	src/Cryptol/Parser/Token.hs
#	src/Cryptol/Transform/AddModParams.hs
#	src/Cryptol/TypeCheck/Error.hs
#	src/Cryptol/TypeCheck/Infer.hs
#	src/Cryptol/TypeCheck/InferTypes.hs

This fixes #1439

See the comment on the new function `selectorScope`
for details.

When we find an undefined name we record an error,
but we also generate a fake name, so that we can continue
processing and report other errors.  It is important
that we don't try to use this fake name.

This commit corrects this behavior where we'd try to get
information about an undefined intrface submodule.

Fixes #1440

# Conflicts:
#	docs/RefMan/_build/doctrees/BasicSyntax.doctree
#	docs/RefMan/_build/doctrees/BasicTypes.doctree
#	docs/RefMan/_build/doctrees/Expressions.doctree
#	docs/RefMan/_build/doctrees/FFI.doctree
#	docs/RefMan/_build/doctrees/Modules.doctree
#	docs/RefMan/_build/doctrees/OverloadedOperations.doctree
#	docs/RefMan/_build/doctrees/RefMan.doctree
#	docs/RefMan/_build/doctrees/TypeDeclarations.doctree
#	docs/RefMan/_build/doctrees/environment.pickle
#	docs/RefMan/_build/html/.buildinfo
#	docs/RefMan/_build/html/BasicSyntax.html
#	docs/RefMan/_build/html/BasicTypes.html
#	docs/RefMan/_build/html/Expressions.html
#	docs/RefMan/_build/html/FFI.html
#	docs/RefMan/_build/html/Modules.html
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#	docs/RefMan/_build/html/TypeDeclarations.html
#	docs/RefMan/_build/html/_static/doctools.js
#	docs/RefMan/_build/html/_static/fonts/Lato-Bold.ttf
#	docs/RefMan/_build/html/_static/fonts/Lato-Regular.ttf
#	docs/RefMan/_build/html/_static/js/modernizr.min.js
#	docs/RefMan/_build/html/_static/searchtools.js
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#	src/Cryptol/ModuleSystem.hs
#	src/Cryptol/ModuleSystem/Base.hs
#	src/Cryptol/ModuleSystem/InstantiateModule.hs
#	src/Cryptol/Parser/AST.hs
#	src/Cryptol/Parser/ParserUtils.hs
#	src/Cryptol/REPL/Command.hs
#	src/Cryptol/Transform/AddModParams.hs
#	src/Cryptol/Transform/Specialize.hs
#	src/Cryptol/TypeCheck/Infer.hs
#	src/Cryptol/TypeCheck/InferTypes.hs
#	src/Cryptol/Utils/Ident.hs

Fixes #1442

At the moment this kind of representes "False" so we need
to handle it.   In the future, we probaly should:
  * add an explicit `TFalse` to distinguish between malformed and False
  * Eliminate obviously false guards when instantiating a funcotr

See #1440

See #1440

…tring

PR #1403 accidentally removed our build coverage for an older Ubuntu LTS
configuration. This patch adds in back and ensures that we don't accidentally
run the tests on this configuration.

…nstead

Fixes #1451

… goals

# Conflicts:
#	src/Cryptol/TypeCheck/Sanity.hs

Fixes #1450

This is mostly for debugging.

When loaded an interface is treated like an empty functor.
Adding this capability would also be useful if we generalize
interfaces to allow for definitions, as discussed in #1457

This also fixes #1456

…paramxs.

Fixes #1458

Not at all tested.