From aaf3ca335d3362e1c28a81d67063d4d84a73154c Mon Sep 17 00:00:00 2001
From: Aleksandr Kirsanov <unserialize.alias@gmail.com>
Date: Fri, 10 May 2024 15:56:11 +0300
Subject: [PATCH] [FunC] Deprecate pragma allow-post-modification

All tests pass: it does not affect hashes (since modifying
variables in a single expression was an error)
---
 .../tests/allow_post_modification.fc          |  2 --
 crypto/func/func.cpp                          |  2 +-
 crypto/func/func.h                            |  2 +-
 crypto/func/gen-abscode.cpp                   | 27 +++++++------------
 crypto/func/parse-func.cpp                    |  6 -----
 5 files changed, 12 insertions(+), 27 deletions(-)

diff --git a/crypto/func/auto-tests/tests/allow_post_modification.fc b/crypto/func/auto-tests/tests/allow_post_modification.fc
index 36a31031..02bfc7ae 100644
--- a/crypto/func/auto-tests/tests/allow_post_modification.fc
+++ b/crypto/func/auto-tests/tests/allow_post_modification.fc
@@ -1,5 +1,3 @@
-#pragma allow-post-modification;
-
 forall X -> tuple unsafe_tuple(X x) asm "NOP";
 
 (int, int) inc(int x, int y) {
diff --git a/crypto/func/func.cpp b/crypto/func/func.cpp
index 7847184f..e3e871b4 100644
--- a/crypto/func/func.cpp
+++ b/crypto/func/func.cpp
@@ -347,6 +347,7 @@ int func_proceed(const std::vector<std::string> &sources, std::ostream &outs, st
 
   funC::define_keywords();
   funC::define_builtins();
+  pragma_allow_post_modification.always_on_and_deprecated("0.5.0");
 
   int ok = 0, proc = 0;
   try {
@@ -365,7 +366,6 @@ int func_proceed(const std::vector<std::string> &sources, std::ostream &outs, st
     if (!proc) {
       throw src::Fatal{"no source files, no output"};
     }
-    pragma_allow_post_modification.check_enable_in_libs();
     pragma_compute_asm_ltr.check_enable_in_libs();
     pragma_remove_unused_functions.check_enable_in_libs();
     return funC::generate_output(outs, errs);
diff --git a/crypto/func/func.h b/crypto/func/func.h
index 14064189..d0fddef6 100644
--- a/crypto/func/func.h
+++ b/crypto/func/func.h
@@ -686,7 +686,7 @@ typedef std::vector<FormalArg> FormalArgList;
 struct AsmOpList;
 
 struct CodeBlob {
-  enum { _AllowPostModification = 1, _ComputeAsmLtr = 2, _ForbidImpure = 4 };
+  enum { _ComputeAsmLtr = 2, _ForbidImpure = 4 };
   int var_cnt, in_var_cnt, op_cnt;
   TypeExpr* ret_type;
   std::string name;
diff --git a/crypto/func/gen-abscode.cpp b/crypto/func/gen-abscode.cpp
index 5e8a8761..52ba33cd 100644
--- a/crypto/func/gen-abscode.cpp
+++ b/crypto/func/gen-abscode.cpp
@@ -286,24 +286,17 @@ std::vector<var_idx_t> pre_compile_tensor(const std::vector<Expr *> args, CodeBl
     res_lists[i] = args[i]->pre_compile(code, lval_globs);
     for (size_t j = 0; j < res_lists[i].size(); ++j) {
       TmpVar& var = code.vars.at(res_lists[i][j]);
-      if (code.flags & CodeBlob::_AllowPostModification) {
-        if (!lval_globs && (var.cls & TmpVar::_Named)) {
-          Op *op = &code.emplace_back(nullptr, Op::_Let, std::vector<var_idx_t>(), std::vector<var_idx_t>());
-          op->set_disabled();
-          var.on_modification.push_back([modified_vars, i, j, op, done = false](const SrcLocation &here) mutable {
-            if (!done) {
-              done = true;
-              modified_vars->push_back({i, j, op});
-            }
-          });
-        } else {
-          var.on_modification.push_back([](const SrcLocation &) {
-          });
-        }
+      if (!lval_globs && (var.cls & TmpVar::_Named)) {
+        Op *op = &code.emplace_back(nullptr, Op::_Let, std::vector<var_idx_t>(), std::vector<var_idx_t>());
+        op->set_disabled();
+        var.on_modification.push_back([modified_vars, i, j, op, done = false](const SrcLocation &here) mutable {
+          if (!done) {
+            done = true;
+            modified_vars->push_back({i, j, op});
+          }
+        });
       } else {
-        var.on_modification.push_back([name = var.to_string()](const SrcLocation &here) {
-            throw src::ParseError{here, PSTRING() << "Modifying local variable " << name
-                                                  << " after using it in the same expression"};
+        var.on_modification.push_back([](const SrcLocation &) {
         });
       }
     }
diff --git a/crypto/func/parse-func.cpp b/crypto/func/parse-func.cpp
index b06933db..6573df70 100644
--- a/crypto/func/parse-func.cpp
+++ b/crypto/func/parse-func.cpp
@@ -266,9 +266,6 @@ void parse_const_decl(Lexer& lex) {
   }
   lex.next();
   CodeBlob code;
-  if (pragma_allow_post_modification.enabled()) {
-    code.flags |= CodeBlob::_AllowPostModification;
-  }
   if (pragma_compute_asm_ltr.enabled()) {
     code.flags |= CodeBlob::_ComputeAsmLtr;
   }
@@ -1219,9 +1216,6 @@ blk_fl::val parse_stmt(Lexer& lex, CodeBlob& code) {
 CodeBlob* parse_func_body(Lexer& lex, FormalArgList arg_list, TypeExpr* ret_type, bool marked_as_pure) {
   lex.expect('{');
   CodeBlob* blob = new CodeBlob{ret_type};
-  if (pragma_allow_post_modification.enabled()) {
-    blob->flags |= CodeBlob::_AllowPostModification;
-  }
   if (pragma_compute_asm_ltr.enabled()) {
     blob->flags |= CodeBlob::_ComputeAsmLtr;
   }