Proto/Michelson: fix `PAIR k` annots

Context

The PAIR k instruction currently converts @ annotations on the stack to % annotations. For example, PAIR 2 works like PAIR %@ %@.

This causes troubles with typing, for example, this typechecks:

{ parameter unit;
  storage unit;
  code { SENDER @foo; SOURCE @bar; PAIR 2;
         SOURCE @foo; SENDER @bar; PAIR 2;
         COMPARE; DROP;
         CDR; NIL operation; PAIR } }

but it fails to typecheck if the @foo and @bar annots are removed.

This makes it difficult to use PAIR k in a compiler, because it may cause type errors.

This change fixes the problem by merely removing the behavior. PAIR k will put no % annotations at all on the result.

An alternative could be to allow the user to specify the field annotations (allowing the user to opt in to the current behavior using %@) but this does not seem important.

Checklist

• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, the Development Version section of CHANGES.md for everything else).
• Select suitable reviewers using the Reviewers field below.

requested review from @rafoo_

added michelson ⚗ proto labels

marked the checklist item Select suitable reviewers using the Reviewers field below. as completed

added 1 commit

• 8e60ac2c - add changelog entry

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marked the checklist item For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, the Development Version section of CHANGES.md for everything else). as completed

Thank you for your contribution , I have one remark:

• There are changes to proto-alpha:
  • → src/proto_alpha/lib_protocol/script_ir_translator.ml
  • → Please make sure changes are properly tagged Proto: and protocol reviewers are alerted..

---

I,  , ran this inspection on Sun, 16 May 2021 22:12:46 0000. I usually run inspections every 6 hours and will try to edit my own comment if I have any updates. For more information see the Tezos documentation.

added 1 commit

• 57d07789 - lint

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The code looks good to me. My only comments are about the test.

assigned to @yrg

mentioned in merge request ligolang/ligo!1102 (merged)

added prioritymedium label

requested review from @mbouaziz

added priorityhigh typebug labels and removed prioritymedium label

added 308 commits

• 57d07789...f7e13378 - 305 commits from branch tezos:master
• ec55bd82 - Proto/Michelson: fix `PAIR k` annots
• 7fff8c4d - add changelog entry
• ca5f5290 - lint

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I have tested that the proposed script:

parameter unit;
storage unit;
code { SENDER; SOURCE; PAIR 2;
       SOURCE; SENDER; PAIR 2;
       COMPARE; DROP;
       CDR; NIL operation; PAIR }

is considered ill-typed before this patch and well-tyed after this patch.

added 167 commits

• ca5f5290...f0e415b3 - 164 commits from branch tezos:master
• ceee334f - Proto/Michelson: fix `PAIR k` annots
• 502b65d3 - add changelog entry
• 9cd1c832 - lint

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added 2 commits

• 83206880 - Proto/Michelson: fix `PAIR k` annots
• ab57da72 - add changelog entry

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added 3 commits

• 018749d1 - Proto/Michelson: fix `PAIR k` annots
• 92ad0496 - Tests/Michelson: add a non-regression test for annotations in PAIR k
• e7bcadc8 - add changelog entry

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