[Bug #21629] Initialize `struct RString`

2 files changed, 4 insertions, 1 deletions

diff --git a/include/ruby/internal/core/rbasic.h b/include/ruby/internal/core/rbasic.h
index 35af03f7c8..63cdff8e09 100644
--- a/include/ruby/internal/core/rbasic.h
+++ b/include/ruby/internal/core/rbasic.h
@@ -115,6 +115,9 @@ RBasic {
 #endif
     {
     }
+# define RBASIC_INIT RBasic()
+#else
+# define RBASIC_INIT {RBIMPL_VALUE_NULL}
 #endif
 };
 
diff --git a/include/ruby/internal/core/rstring.h b/include/ruby/internal/core/rstring.h
index 0bca74e688..9cf9daa97c 100644
--- a/include/ruby/internal/core/rstring.h
+++ b/include/ruby/internal/core/rstring.h
@@ -395,7 +395,7 @@ rbimpl_rstring_getmem(VALUE str)
     }
     else {
         /* Expecting compilers to optimize this on-stack struct away. */
-        struct RString retval;
+        struct RString retval = {RBASIC_INIT};
         retval.len = RSTRING_LEN(str);
         retval.as.heap.ptr = RSTRING(str)->as.embed.ary;
         return retval;