diff --git a/CMakeLists.txt b/CMakeLists.txt
index c13a0610b46b..0112368fba83 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -130,7 +130,7 @@ endif ()
 
 if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
   set(PEDANTIC_COMPILE_FLAGS -Wall -Wextra -pedantic -Wconversion
-      -Wno-sign-conversion -Wdeprecated -Wweak-vtables)
+      -Wdeprecated -Wweak-vtables)
   check_cxx_compiler_flag(-Wzero-as-null-pointer-constant HAS_NULLPTR_WARNING)
   if (HAS_NULLPTR_WARNING)
     set(PEDANTIC_COMPILE_FLAGS ${PEDANTIC_COMPILE_FLAGS}
diff --git a/test/format-test.cc b/test/format-test.cc
index d0a38f258975..33e620f70d74 100644
--- a/test/format-test.cc
+++ b/test/format-test.cc
@@ -1828,14 +1828,18 @@ class mock_arg_formatter
   }
 
   template <typename T>
-  typename std::enable_if<fmt::detail::is_integral<T>::value, iterator>::type
+  typename std::enable_if<fmt::detail::is_integral<T>::value &&
+                              fmt::detail::is_signed<T>::value,
+                          iterator>::type
   operator()(T value) {
     call(value);
     return base::operator()(value);
   }
 
   template <typename T>
-  typename std::enable_if<!fmt::detail::is_integral<T>::value, iterator>::type
+  typename std::enable_if<!(fmt::detail::is_integral<T>::value &&
+                            fmt::detail::is_signed<T>::value),
+                          iterator>::type
   operator()(T value) {
     return base::operator()(value);
   }
diff --git a/test/ranges-test.cc b/test/ranges-test.cc
index 518e7ba26f95..19122047efcf 100644
--- a/test/ranges-test.cc
+++ b/test/ranges-test.cc
@@ -175,15 +175,17 @@ template <typename T> class non_const_only_range {
 };
 
 TEST(RangesTest, JoinRange) {
-  non_const_only_range<int> x(3, 0);
+  non_const_only_range<int> x(3u, 0);
   EXPECT_EQ("0,0,0", fmt::format("{}", fmt::join(x, ",")));
-  EXPECT_EQ("0,0,0",
-            fmt::format("{}", fmt::join(non_const_only_range<int>(3, 0), ",")));
+  EXPECT_EQ(
+      "0,0,0",
+      fmt::format("{}", fmt::join(non_const_only_range<int>(3u, 0), ",")));
 
-  std::vector<int> y(3, 0);
+  std::vector<int> y(3u, 0);
   EXPECT_EQ("0,0,0", fmt::format("{}", fmt::join(y, ",")));
-  EXPECT_EQ("0,0,0", fmt::format("{}", fmt::join(std::vector<int>(3, 0), ",")));
+  EXPECT_EQ("0,0,0",
+            fmt::format("{}", fmt::join(std::vector<int>(3u, 0), ",")));
 
-  const std::vector<int> z(3, 0);
+  const std::vector<int> z(3u, 0);
   EXPECT_EQ("0,0,0", fmt::format("{}", fmt::join(z, ",")));
 }