Fix some error handling in FunC (#599)

crypto/func/builtins.cpp

@@ -266,7 +266,7 @@ int emulate_div(int a, int b) {
   if ((b & (VarDescr::_NonZero | VarDescr::_Bit)) == (VarDescr::_NonZero | VarDescr::_Bit)) {
     return a;
   } else if ((b & (VarDescr::_NonZero | VarDescr::_Bool)) == (VarDescr::_NonZero | VarDescr::_Bool)) {
-    return emulate_negate(b);
+    return emulate_negate(a);
   }
   if (b & VarDescr::_Zero) {
     return VarDescr::_Int | VarDescr::_Nan;

crypto/func/codegen.cpp

@@ -663,12 +663,20 @@ bool Op::generate_code_step(Stack& stack) {
         stack.o << "REPEAT:<{";
         stack.o.indent();
         stack.forget_const();
-        StackLayout layout1 = stack.vars();
-        stack.mode &= ~Stack::_InlineFunc;
-        stack.mode |= Stack::_NeedRetAlt;
-        block0->generate_code_all(stack);
-        stack.enforce_state(std::move(layout1));
-        stack.opt_show();
+        if (block0->noreturn()) {
+          Stack stack_copy{stack};
+          StackLayout layout1 = stack.vars();
+          stack_copy.mode &= ~Stack::_InlineFunc;
+          stack_copy.mode |= Stack::_NeedRetAlt;
+          block0->generate_code_all(stack_copy);
+        } else {
+          StackLayout layout1 = stack.vars();
+          stack.mode &= ~Stack::_InlineFunc;
+          stack.mode |= Stack::_NeedRetAlt;
+          block0->generate_code_all(stack);
+          stack.enforce_state(std::move(layout1));
+          stack.opt_show();
+        }
         stack.o.undent();
         stack.o << "}>";
         return true;

crypto/func/func.h

@@ -388,7 +388,7 @@ struct VarDescr {
     return val & _Const;
   }
   bool is_int_const() const {
-    return (val & (_Int | _Const)) == (_Int | _Const);
+    return (val & (_Int | _Const)) == (_Int | _Const) && int_const.not_null();
   }
   bool always_nonpos() const {
     return val & _Neg;

crypto/func/gen-abscode.cpp

@@ -355,6 +355,9 @@ std::vector<var_idx_t> Expr::pre_compile(CodeBlob& code, std::vector<std::pair<S
       return args[0]->pre_compile(code, lval_globs);
     case _Var:
     case _Hole:
+      if (val < 0) {
+        throw src::ParseError{here, "unexpected variable definition"};
+      }
       return {val};
     case _VarApply:
       if (args[0]->cls == _Glob) {

crypto/func/parse-func.cpp

@@ -1372,7 +1372,7 @@ std::vector<TypeExpr*> parse_type_var_list(Lexer& lex) {
     }
     auto loc = lex.cur().loc;
     SymDef* new_sym_def = sym::define_symbol(lex.cur().val, true, loc);
-    if (new_sym_def->value) {
+    if (!new_sym_def || new_sym_def->value) {
       lex.cur().error_at("redefined type variable `", "`");
     }
     auto var = TypeExpr::new_var(idx);
@@ -1582,8 +1582,15 @@ void parse_pragma(Lexer& lex) {
     char op = '='; bool eq = false;
     int sem_ver[3] = {0, 0, 0};
     char segs = 1;
+    auto stoi = [&](const std::string& s) {
+      auto R = td::to_integer_safe<int>(s);
+      if (R.is_error()) {
+        lex.cur().error("invalid semver format");
+      }
+      return R.move_as_ok();
+    };
     if (lex.tp() == _Number) {
-      sem_ver[0] = std::stoi(lex.cur().str);
+      sem_ver[0] = stoi(lex.cur().str);
     } else if (lex.tp() == _Ident) {
       auto id1 = lex.cur().str;
       char ch1 = id1[0];
@@ -1600,9 +1607,9 @@ void parse_pragma(Lexer& lex) {
         if (id1.length() < 3) {
           lex.cur().error("expected number after comparator");
         }
-        sem_ver[0] = std::stoi(id1.substr(2));
+        sem_ver[0] = stoi(id1.substr(2));
       } else {
-        sem_ver[0] = std::stoi(id1.substr(1));
+        sem_ver[0] = stoi(id1.substr(1));
       }
     } else {
       lex.cur().error("expected semver with optional comparator");
@@ -1612,7 +1619,7 @@ void parse_pragma(Lexer& lex) {
       if (lex.tp() != _Ident || lex.cur().str[0] != '.') {
         lex.cur().error("invalid semver format");
       }
-      sem_ver[1] = std::stoi(lex.cur().str.substr(1));
+      sem_ver[1] = stoi(lex.cur().str.substr(1));
       segs = 2;
       lex.next();
     }
@@ -1620,7 +1627,7 @@ void parse_pragma(Lexer& lex) {
       if (lex.tp() != _Ident || lex.cur().str[0] != '.') {
         lex.cur().error("invalid semver format");
       }
-      sem_ver[2] = std::stoi(lex.cur().str.substr(1));
+      sem_ver[2] = stoi(lex.cur().str.substr(1));
       segs = 3;
       lex.next();
     }
@@ -1630,7 +1637,7 @@ void parse_pragma(Lexer& lex) {
     std::string s;
     for (int idx = 0; idx < 3; idx++) {
       std::getline(iss, s, '.');
-      func_ver[idx] = std::stoi(s);
+      func_ver[idx] = stoi(s);
     }
     // End parsing embedded semver
     std::string semver_expr;