diff --git a/libcxx/include/__format/formatter_string.h b/libcxx/include/__format/formatter_string.h
--- a/libcxx/include/__format/formatter_string.h
+++ b/libcxx/include/__format/formatter_string.h
@@ -52,7 +52,7 @@
   _LIBCPP_HIDE_FROM_ABI constexpr void set_debug_format() { __parser_.__type_ = __format_spec::__type::__debug; }
 #  endif
 
-  __format_spec::__parser<_CharT> __parser_;
+  __format_spec::__parser<_CharT> __parser_{.__alignment_ = __format_spec::__alignment::__left};
 };
 
 // Formatter const char*.
diff --git a/libcxx/test/std/utilities/format/format.functions/format_tests.h b/libcxx/test/std/utilities/format/format.functions/format_tests.h
--- a/libcxx/test/std/utilities/format/format.functions/format_tests.h
+++ b/libcxx/test/std/utilities/format/format.functions/format_tests.h
@@ -201,6 +201,7 @@
   check(SV("hello universe and world"), SV("hello {1} and {0}"), world, universe);
 
   check(SV("hello world"), SV("hello {:_>}"), world);
+  check(SV("hello world   "), SV("hello {:8}"), world);
   check(SV("hello    world"), SV("hello {:>8}"), world);
   check(SV("hello ___world"), SV("hello {:_>8}"), world);
   check(SV("hello _world__"), SV("hello {:_^8}"), world);
@@ -883,7 +884,6 @@
   // ***** Char type *****
   // *** align-fill & width ***
   check(SV("answer is '*     '"), SV("answer is '{:6}'"), CharT('*'));
-
   check(SV("answer is '     *'"), SV("answer is '{:>6}'"), CharT('*'));
   check(SV("answer is '*     '"), SV("answer is '{:<6}'"), CharT('*'));
   check(SV("answer is '  *   '"), SV("answer is '{:^6}'"), CharT('*'));