(Finsert_file_contents): If a coding system is

specified explicitly on visiting a new file, set
buffer-file-coding system of the new buffer to the specified one.

src/fileio.c

@@ -3164,6 +3164,8 @@ This does code conversion according to the value of\n\
 	report_file_error ("Opening input file", Fcons (orig_filename, Qnil));
       st.st_mtime = -1;
       how_much = 0;
+      if (!NILP (Vcoding_system_for_read))
+	current_buffer->buffer_file_coding_system = Vcoding_system_for_read;
       goto notfound;
     }