Use auto where type does not matter (and is likely signed)

This avoids conversion warnings with Visual Studio.

Author: tautschnig

jbmc/unit/java_bytecode/java_bytecode_instrument/virtual_call_null_checks.cpp

@@ -60,11 +60,10 @@ SCENARIO(
       {
         // This just checks that the class actually makes the expected call,
         // i.e. that it hasn't been optimised away or similar.
-        std::size_t found_virtualmethod_calls =
-          std::count_if(
-            main_function.body.instructions.begin(),
-            main_function.body.instructions.end(),
-            is_expected_virtualmethod_call);
+        auto found_virtualmethod_calls = std::count_if(
+          main_function.body.instructions.begin(),
+          main_function.body.instructions.end(),
+          is_expected_virtualmethod_call);
 
         REQUIRE(found_virtualmethod_calls == 1);
       }

unit/util/irep.cpp

@@ -148,7 +148,7 @@ SCENARIO("irept_memory", "[core][utils][irept]")
       irep.add("a_new_element", irep2);
       REQUIRE(!irept::is_comment("a_new_element"));
       REQUIRE(irep.find("a_new_element").id() == "second_irep");
-      std::size_t named_sub_size =
+      auto named_sub_size =
         std::distance(irep.get_named_sub().begin(), irep.get_named_sub().end());
       REQUIRE(named_sub_size == 1);
 

unit/util/range.cpp

@@ -406,8 +406,7 @@ SCENARIO(
     THEN("A range of made from the vector can be filtered.")
     {
       const auto odds_filter = make_range(input).filter(is_odd);
-      const std::size_t total =
-        std::distance(odds_filter.begin(), odds_filter.end());
+      const auto total = std::distance(odds_filter.begin(), odds_filter.end());
       REQUIRE(total == 5);
       auto iterator = odds_filter.begin();
       REQUIRE((iterator++)->value == 1);