Do not use redundant comparison with true or false

We generally don't do so, and using it in selected places is an unnecessary
surprise to the (code) reader.

Author: tautschnig

jbmc/src/java_bytecode/java_static_initializers.cpp

@@ -656,7 +656,7 @@ codet get_clinit_wrapper_body(
   //
   // java::C::clinit_wrapper()
   // {
-  //   if (java::C::clinit_already_run == false)
+  //   if (!java::C::clinit_already_run)
   //   {
   //     java::C::clinit_already_run = true; // before recursive calls!
   //

src/cpp/cpp_typecheck_code.cpp

@@ -258,7 +258,7 @@ void cpp_typecheckt::typecheck_member_initializer(codet &code)
     // a reference member
     if(symbol_expr.id() == ID_dereference &&
        symbol_expr.op0().id() == ID_member &&
-       symbol_expr.get_bool(ID_C_implicit) == true)
+       symbol_expr.get_bool(ID_C_implicit))
     {
       // treat references as normal pointers
       exprt tmp = symbol_expr.op0();
@@ -286,7 +286,7 @@ void cpp_typecheckt::typecheck_member_initializer(codet &code)
 
       if(symbol_expr.id() == ID_dereference &&
          symbol_expr.op0().id() == ID_member &&
-         symbol_expr.get_bool(ID_C_implicit) == true)
+         symbol_expr.get_bool(ID_C_implicit))
       {
         // treat references as normal pointers
         exprt tmp = symbol_expr.op0();

src/cpp/cpp_typecheck_conversions.cpp

@@ -1643,7 +1643,7 @@ bool cpp_typecheckt::const_typecast(
   const typet &type,
   exprt &new_expr)
 {
-  assert(is_reference(expr.type())==false);
+  PRECONDITION(!is_reference(expr.type()));
 
   exprt curr_expr=expr;
 

src/solvers/smt2/smt2_conv.cpp

@@ -4102,7 +4102,7 @@ void smt2_convt::set_to(const exprt &expr, bool value)
   // special treatment for "set_to(a=b, true)" where
   // a is a new symbol
 
-  if(expr.id()==ID_equal && value==true)
+  if(expr.id() == ID_equal && value)
   {
     const equal_exprt &equal_expr=to_equal_expr(expr);
 

unit/util/optional.cpp

@@ -12,21 +12,21 @@
 TEST_CASE("Optional without a value", "[core][util][optional]")
 {
   optionalt<bool> maybe_value;
-  REQUIRE(maybe_value.has_value()==false);
+  REQUIRE(!maybe_value.has_value());
   REQUIRE_THROWS_AS(maybe_value.value(), bad_optional_accesst);
 }
 
 TEST_CASE("Optional with a value", "[core][util][optional]")
 {
   optionalt<bool> maybe_value=false;
   REQUIRE(maybe_value.has_value());
-  REQUIRE(maybe_value.value()==false);
+  REQUIRE(!maybe_value.value());
 }
 
 
 TEST_CASE("Optional with a value (operator access)", "[core][util][optional]")
 {
   optionalt<bool> maybe_value=true;
   REQUIRE(maybe_value.has_value());
-  REQUIRE(*maybe_value==true);
+  REQUIRE(*maybe_value);
 }

unit/util/replace_symbol.cpp

@@ -32,17 +32,17 @@ TEST_CASE("Replace all symbols in expression", "[core][util][replace_symbol]")
   REQUIRE(r.replaces_symbol("a"));
   REQUIRE(r.get_expr_map().size() == 1);
 
-  REQUIRE(r.replace(binary) == false);
+  REQUIRE(!r.replace(binary));
   REQUIRE(binary.op0() == other_expr);
 
-  REQUIRE(r.replace(s1) == false);
+  REQUIRE(!r.replace(s1));
   REQUIRE(s1 == other_expr);
 
-  REQUIRE(r.replace(s2) == true);
+  REQUIRE(r.replace(s2));
   REQUIRE(s2 == symbol_exprt("b", typet("some_type")));
 
 
-  REQUIRE(r.replace(array_type) == false);
+  REQUIRE(!r.replace(array_type));
   REQUIRE(array_type.size() == other_expr);
 
   REQUIRE(r.erase("a") == 1);
@@ -65,7 +65,7 @@ TEST_CASE("Lvalue only", "[core][util][replace_symbol]")
   address_of_aware_replace_symbolt r;
   r.insert(s1, c);
 
-  REQUIRE(r.replace(binary) == false);
+  REQUIRE(!r.replace(binary));
   REQUIRE(binary.op0() == address_of_exprt(s1));
   const index_exprt &index_expr =
     to_index_expr(to_address_of_expr(binary.op1()).object());
@@ -76,7 +76,7 @@ TEST_CASE("Lvalue only", "[core][util][replace_symbol]")
   r.erase("a");
   r.insert(s1, address_of);
 
-  REQUIRE(r.replace(binary) == true);
+  REQUIRE(r.replace(binary));
   REQUIRE(binary.op0() == address_of_exprt(s1));
 }
 
@@ -96,7 +96,7 @@ TEST_CASE("Replace always", "[core][util][replace_symbol]")
   unchecked_replace_symbolt r;
   r.insert(s1, c);
 
-  REQUIRE(r.replace(binary) == false);
+  REQUIRE(!r.replace(binary));
   REQUIRE(binary.op0() == address_of_exprt(c));
   const index_exprt &index_expr =
     to_index_expr(to_address_of_expr(binary.op1()).object());