2 files changed, 30 insertions, 1 deletions
diff --git a/include/ruby/internal/encoding/coderange.h b/include/ruby/internal/encoding/coderange.h
index 7a81208c9e..c89f871518 100644
--- a/include/ruby/internal/encoding/coderange.h
+++ b/include/ruby/internal/encoding/coderange.h
@@ -79,7 +79,7 @@ RBIMPL_ATTR_CONST()
 static inline bool
 RB_ENC_CODERANGE_CLEAN_P(enum ruby_coderange_type cr)
 {
-    return rb_enc_coderange_clean_p(cr);
+    return rb_enc_coderange_clean_p(RBIMPL_CAST((int)cr));
 }
 
 RBIMPL_ATTR_PURE_UNLESS_DEBUG()
diff --git a/include/ruby/internal/encoding/string.h b/include/ruby/internal/encoding/string.h
index 2cfa91c01e..ea78cf23f3 100644
--- a/include/ruby/internal/encoding/string.h
+++ b/include/ruby/internal/encoding/string.h
@@ -264,6 +264,14 @@ VALUE rb_str_conv_enc(VALUE str, rb_encoding *from, rb_encoding *to);
 VALUE rb_str_conv_enc_opts(VALUE str, rb_encoding *from, rb_encoding *to, int ecflags, VALUE ecopts);
 
 /**
+ * @private
+ *
+ * This is an implementation detail of rb_enc_str_coderange().  Don't use this
+ * directly.
+ **/
+int rbimpl_enc_str_coderange_scan(VALUE str);
+
+/**
  * Scans the passed string to collect  its code range.  Because a Ruby's string
  * is mutable, its contents  change from time to time; so  does its code range.
  * A  long-lived string  tends  to fall  back to  ::RUBY_ENC_CODERANGE_UNKNOWN.
@@ -275,6 +283,27 @@ VALUE rb_str_conv_enc_opts(VALUE str, rb_encoding *from, rb_encoding *to, int ec
 int rb_enc_str_coderange(VALUE str);
 
 /**
+ * Scans the passed string to collect  its code range.  Because a Ruby's string
+ * is mutable, its contents  change from time to time; so  does its code range.
+ * A  long-lived string  tends  to fall  back to  ::RUBY_ENC_CODERANGE_UNKNOWN.
+ * This API scans it and re-assigns a fine-grained code range constant.
+ *
+ * @param[out]  str  A string.
+ * @return      An enum ::ruby_coderange_type.
+ */
+static inline int
+rb_enc_str_coderange_inline(VALUE str)
+{
+    int cr = ENC_CODERANGE(str);
+    if (cr == ENC_CODERANGE_UNKNOWN) {
+        cr = rbimpl_enc_str_coderange_scan(str);
+    }
+    return cr;
+}
+
+#define rb_enc_str_coderange rb_enc_str_coderange_inline
+
+/**
  * Scans the passed string until it finds something odd.  Returns the number of
  * bytes scanned.  As the name implies this is suitable for repeated call.  One
  * of its application is `IO#readlines`.   The method reads from its receiver's