Cryptol bindings escape functions

[sauclovian-g]

Observe:

sawscript> let f () = do { let {{ y = 3 : [8] }}; return (); };
sawscript> f ()
sawscript> return (eval_int {{ y }});
[01:55:32.455] 3
sawscript> 

This definitely violates the principle of least surprise.

(Note that it's not the same as #2243, but obviously related.)

[brianhuffman]

This FIXME comment is relevant:

saw-script/saw-script/src/SAWScript/Interpreter.hs

Lines 323 to 331 in 603fd4e

	SS.StmtCode _ s : ss ->
	do sc <- getSharedContext
	rw <- getMergedEnv
	ce' <- io $ CEnv.parseDecls sc (rwCryptol rw) $ locToInput s
	-- FIXME: Local bindings get saved into the global cryptol environment here.
	-- We should change parseDecls to return only the new bindings instead.
	putTopLevelRW $ rw{rwCryptol = ce'}
	interpretStmts ss

(Git blame says that I wrote that comment in commit 079d746 from 2015.)

[sauclovian-g]

Right, there's only one Cryptol environment and it's in TopLevelRW so it's global.

I'm intending to rearrange how the local environments work because the current state is messy and interacts badly with the typechecker. Haven't figured out how it should be yet though...