Fix warnings from Travis

include/fmt/prepare.h

@@ -383,7 +383,6 @@ template <typename Format> class compiletime_prepared_parts_type_provider {
    private:
     FMT_CONSTEXPR const char_type* find_matching_brace(const char_type* begin,
                                                        const char_type* end) {
-      FMT_CONSTEXPR_DECL const basic_string_view<char_type> text = Format{};
       unsigned braces_counter{0u};
       for (; begin != end; ++begin) {
         if (*begin == '{') {

test/ostream-test.cc

@@ -154,7 +154,7 @@ TEST(OStreamTest, WriteToOStreamMaxSize) {
     EXPECT_CALL(streambuf, xsputn(data, static_cast<std::streamsize>(n)))
         .WillOnce(testing::Return(max_streamsize));
     data += n;
-    size -= static_cast<std::size_t>(n);
+    size -= n;
   } while (size != 0);
   fmt::internal::write(os, buffer);
 }

test/prepare-test.cc

@@ -169,7 +169,6 @@ TEST(PrepareTest, FormatPart_ComparisonOperators) {
     auto rhs = format_part(specs);
     EXPECT_EQ(lhs, rhs);
 
-    const auto specs_text = fmt::string_view("<10");
     specs.parsed_specs = prepared_specs();
     lhs = format_part(specs);
     rhs = format_part(specs);
@@ -191,8 +190,6 @@ TEST(PrepareTest, FormatPart_ComparisonOperators) {
     rhs = format_part(rhs_spec);
     EXPECT_NE(lhs, rhs);
 
-    const auto lhs_specs_text = fmt::string_view("<10");
-    const auto rhs_specs_text = fmt::string_view("<42");
     lhs_spec = format_part::specification(specs_argument_id);
     rhs_spec = format_part::specification(specs_argument_id);
     lhs_spec.parsed_specs.precision = 1;
@@ -202,7 +199,6 @@ TEST(PrepareTest, FormatPart_ComparisonOperators) {
     EXPECT_NE(lhs, rhs);
   }
   {
-    const auto specs_text = fmt::string_view{"<10"};
     const auto specs_argument_id = 0u;
     const auto specs_named_argument_id =
         fmt::internal::string_view_metadata(0, 42);
@@ -623,7 +619,7 @@ template <typename T> struct user_allocator {
   template <typename U> user_allocator(const user_allocator<U>&) {}
 
   pointer allocate(size_type cnt,
-                   typename std::allocator<void>::const_pointer = 0) {
+                   typename std::allocator<void>::const_pointer = FMT_NULL) {
     return new value_type[cnt];
   }
 
@@ -633,8 +629,8 @@ template <typename T> struct user_allocator {
 
   void destroy(pointer p) { (*p).~value_type(); }
 
-  bool operator==(const user_allocator& other) const { return true; }
-  bool operator!=(const user_allocator& other) const { return false; }
+  bool operator==(const user_allocator&) const { return true; }
+  bool operator!=(const user_allocator&) const { return false; }
 };
 
 TEST(PrepareTest, PassUserTypeFormat) {