diff --git a/example/json-to-cbor/json-to-cbor.cc b/example/json-to-cbor/json-to-cbor.cc
index d5ad630..d8d7a3d 100644
--- a/example/json-to-cbor/json-to-cbor.cc
+++ b/example/json-to-cbor/json-to-cbor.cc
@@ -248,11 +248,6 @@
     return write_dst(val ? "\xF5" : "\xF4", 1);
   }
 
-  virtual std::string AppendI64(int64_t val) {
-    return (val >= 0) ? Append(static_cast<uint64_t>(val), 0x00)
-                      : Append(static_cast<uint64_t>(-(val + 1)), 0x20);
-  }
-
   virtual std::string AppendF64(double val) {
     uint8_t c[9];
     wuffs_base__lossy_value_u16 lv16 =
@@ -275,7 +270,12 @@
     return write_dst(&c[0], 9);
   }
 
-  virtual std::string AppendString(std::string&& val) {
+  virtual std::string AppendI64(int64_t val) {
+    return (val >= 0) ? Append(static_cast<uint64_t>(val), 0x00)
+                      : Append(static_cast<uint64_t>(-(val + 1)), 0x20);
+  }
+
+  virtual std::string AppendTextString(std::string&& val) {
     TRY(Append(val.size(), 0x60));
     return write_dst(val.data(), val.size());
   }
diff --git a/example/jsonfindptrs/jsonfindptrs.cc b/example/jsonfindptrs/jsonfindptrs.cc
index 78c1050..b5dcef1 100644
--- a/example/jsonfindptrs/jsonfindptrs.cc
+++ b/example/jsonfindptrs/jsonfindptrs.cc
@@ -441,7 +441,7 @@
     return Append(std::move(jt));
   }
 
-  virtual std::string AppendString(std::string&& val) {
+  virtual std::string AppendTextString(std::string&& val) {
     JsonThing jt;
     jt.kind = JsonThing::Kind::String;
     jt.value.s = std::move(val);
diff --git a/internal/cgen/auxiliary/json.cc b/internal/cgen/auxiliary/json.cc
index f2edd02..e40b308 100644
--- a/internal/cgen/auxiliary/json.cc
+++ b/internal/cgen/auxiliary/json.cc
@@ -27,6 +27,10 @@
     : error_message(std::move(error_message0)),
       cursor_position(cursor_position0) {}
 
+void DecodeJsonCallbacks::Done(DecodeJsonResult& result,
+                               sync_io::Input& input,
+                               IOBuffer& buffer) {}
+
 DecodeJsonResult  //
 DecodeJson(DecodeJsonCallbacks&& callbacks,
            sync_io::Input&& input,
@@ -160,7 +164,7 @@
           if (token.continued()) {
             continue;
           }
-          ret_error_message = callbacks.AppendString(std::move(str));
+          ret_error_message = callbacks.AppendTextString(std::move(str));
           str.clear();
           goto parsed_a_value;
         }
@@ -230,6 +234,7 @@
                     0x7FFFFFFFFFFFFFFFul));
             goto parsed_a_value;
           }
+          goto fail;
         }
       }
 
diff --git a/internal/cgen/auxiliary/json.hh b/internal/cgen/auxiliary/json.hh
index 5625251..b3998f6 100644
--- a/internal/cgen/auxiliary/json.hh
+++ b/internal/cgen/auxiliary/json.hh
@@ -33,9 +33,9 @@
 
   virtual std::string AppendNull() = 0;
   virtual std::string AppendBool(bool val) = 0;
-  virtual std::string AppendI64(int64_t val) = 0;
   virtual std::string AppendF64(double val) = 0;
-  virtual std::string AppendString(std::string&& val) = 0;
+  virtual std::string AppendI64(int64_t val) = 0;
+  virtual std::string AppendTextString(std::string&& val) = 0;
 
   // Push and Pop are called for container nodes: JSON arrays (lists) and JSON
   // objects (dictionaries).
@@ -62,7 +62,7 @@
   // as DecodeJson may then de-allocate the backing array.
   virtual void Done(DecodeJsonResult& result,
                     sync_io::Input& input,
-                    IOBuffer& buffer) = 0;
+                    IOBuffer& buffer);
 };
 
 // DecodeJson calls callbacks based on the JSON-formatted data in input.
diff --git a/internal/cgen/data/data.go b/internal/cgen/data/data.go
index 2df619d..140349f 100644
--- a/internal/cgen/data/data.go
+++ b/internal/cgen/data/data.go
@@ -647,20 +647,21 @@
 	""
 
 const AuxJsonCc = "" +
-	"// ---------------- Auxiliary - JSON\n\n#if !defined(WUFFS_CONFIG__MODULES) || defined(WUFFS_CONFIG__MODULE__AUX__JSON)\n\n#include <utility>\n\nnamespace wuffs_aux {\n\nDecodeJsonResult::DecodeJsonResult(std::string&& error_message0,\n                                   uint64_t cursor_position0)\n    : error_message(std::move(error_message0)),\n      cursor_position(cursor_position0) {}\n\nDecodeJsonResult  //\nDecodeJson(DecodeJsonCallbacks&& callbacks,\n           sync_io::Input&& input,\n           wuffs_base__slice_u32 quirks) {\n  // Prepare the wuffs_base__io_buffer and the resultant error_message.\n  wuffs_base__io_buffer* io_buf = input.BringsItsOwnIOBuffer();\n  wuffs_base__io_buffer fallback_io_buf = wuffs_base__empty_io_buffer();\n  std::unique_ptr<uint8_t[]> fallback_io_array(nullptr);\n  if (!io_buf) {\n    fallback_io_array = std::unique_ptr<uint8_t[]>(new uint8_t[4096]);\n    fallback_io_buf = wuffs_base__ptr_u8__writer(fallback_io_array.get(), 4096);\n    io_buf = &fallback_io_buf;\n  }\n  size_t cursor_index = 0;\n  s" +
-	"td::string ret_error_message;\n  std::string io_error_message;\n\n  do {\n    // Prepare the low-level JSON decoder.\n    wuffs_json__decoder::unique_ptr dec = wuffs_json__decoder::alloc();\n    if (!dec) {\n      ret_error_message = \"wuffs_aux::JsonDecoder: out of memory\";\n      goto done;\n    }\n    for (size_t i = 0; i < quirks.len; i++) {\n      dec->set_quirk_enabled(quirks.ptr[i], true);\n    }\n\n    // Prepare the wuffs_base__tok_buffer.\n    wuffs_base__token tok_array[256];\n    wuffs_base__token_buffer tok_buf =\n        wuffs_base__slice_token__writer(wuffs_base__make_slice_token(\n            &tok_array[0], (sizeof(tok_array) / sizeof(tok_array[0]))));\n    wuffs_base__status tok_status = wuffs_base__make_status(nullptr);\n\n    // Prepare other state.\n    uint32_t depth = 0;\n    std::string str;\n\n    // Loop, doing these two things:\n    //  1. Get the next token.\n    //  2. Process that token.\n    while (true) {\n      // 1. Get the next token.\n\n      while (tok_buf.meta.ri >= tok_buf.meta.wi) {\n        if (tok_sta" +
-	"tus.repr == nullptr) {\n          // No-op.\n        } else if (tok_status.repr == wuffs_base__suspension__short_write) {\n          tok_buf.compact();\n        } else if (tok_status.repr == wuffs_base__suspension__short_read) {\n          // Read from input to io_buf.\n          if (!io_error_message.empty()) {\n            ret_error_message = std::move(io_error_message);\n            goto done;\n          } else if (cursor_index != io_buf->meta.ri) {\n            ret_error_message =\n                \"wuffs_aux::JsonDecoder: internal error: bad cursor_index\";\n            goto done;\n          } else if (io_buf->meta.closed) {\n            ret_error_message =\n                \"wuffs_aux::JsonDecoder: internal error: io_buf is closed\";\n            goto done;\n          }\n          io_buf->compact();\n          if (io_buf->meta.wi >= io_buf->data.len) {\n            ret_error_message =\n                \"wuffs_aux::JsonDecoder: internal error: io_buf is full\";\n            goto done;\n          }\n          cursor_index = io_buf->me" +
-	"ta.ri;\n          io_error_message = input.CopyIn(io_buf);\n        } else {\n          ret_error_message = tok_status.message();\n          goto done;\n        }\n\n        if (WUFFS_JSON__DECODER_WORKBUF_LEN_MAX_INCL_WORST_CASE != 0) {\n          ret_error_message =\n              \"wuffs_aux::JsonDecoder: internal error: bad WORKBUF_LEN\";\n          goto done;\n        }\n        wuffs_base__slice_u8 work_buf = wuffs_base__empty_slice_u8();\n        tok_status = dec->decode_tokens(&tok_buf, io_buf, work_buf);\n      }\n\n      wuffs_base__token token = tok_buf.data.ptr[tok_buf.meta.ri++];\n      uint64_t token_len = token.length();\n      if ((io_buf->meta.ri < cursor_index) ||\n          ((io_buf->meta.ri - cursor_index) < token_len)) {\n        ret_error_message =\n            \"wuffs_aux::JsonDecoder: internal error: bad token indexes\";\n        goto done;\n      }\n      uint8_t* token_ptr = io_buf->data.ptr + cursor_index;\n      cursor_index += token_len;\n\n      // 2. Process that token.\n\n      int64_t vbc = token.value_base_c" +
-	"ategory();\n      uint64_t vbd = token.value_base_detail();\n      switch (vbc) {\n        case WUFFS_BASE__TOKEN__VBC__FILLER:\n          continue;\n\n        case WUFFS_BASE__TOKEN__VBC__STRUCTURE: {\n          if (vbd & WUFFS_BASE__TOKEN__VBD__STRUCTURE__PUSH) {\n            ret_error_message = callbacks.Push(static_cast<uint32_t>(vbd));\n            if (!ret_error_message.empty()) {\n              goto done;\n            }\n            depth++;\n            continue;\n          }\n          ret_error_message = callbacks.Pop(static_cast<uint32_t>(vbd));\n          depth--;\n          goto parsed_a_value;\n        }\n\n        case WUFFS_BASE__TOKEN__VBC__STRING: {\n          if (vbd & WUFFS_BASE__TOKEN__VBD__STRING__CONVERT_0_DST_1_SRC_DROP) {\n            // No-op.\n          } else if (vbd &\n                     WUFFS_BASE__TOKEN__VBD__STRING__CONVERT_1_DST_1_SRC_COPY) {\n            const char* ptr =  // Convert from (uint8_t*).\n                static_cast<const char*>(static_cast<void*>(token_ptr));\n            str.append(ptr" +
-	", token_len);\n          } else {\n            goto fail;\n          }\n          if (token.continued()) {\n            continue;\n          }\n          ret_error_message = callbacks.AppendString(std::move(str));\n          str.clear();\n          goto parsed_a_value;\n        }\n\n        case WUFFS_BASE__TOKEN__VBC__UNICODE_CODE_POINT: {\n          uint8_t u[WUFFS_BASE__UTF_8__BYTE_LENGTH__MAX_INCL];\n          size_t n = wuffs_base__utf_8__encode(\n              wuffs_base__make_slice_u8(\n                  &u[0], WUFFS_BASE__UTF_8__BYTE_LENGTH__MAX_INCL),\n              static_cast<uint32_t>(vbd));\n          const char* ptr =  // Convert from (uint8_t*).\n              static_cast<const char*>(static_cast<void*>(&u[0]));\n          str.append(ptr, n);\n          if (token.continued()) {\n            continue;\n          }\n          goto fail;\n        }\n\n        case WUFFS_BASE__TOKEN__VBC__LITERAL: {\n          ret_error_message =\n              (vbd & WUFFS_BASE__TOKEN__VBD__LITERAL__NULL)\n                  ? callbacks.AppendN" +
-	"ull()\n                  : callbacks.AppendBool(vbd &\n                                         WUFFS_BASE__TOKEN__VBD__LITERAL__TRUE);\n          goto parsed_a_value;\n        }\n\n        case WUFFS_BASE__TOKEN__VBC__NUMBER: {\n          if (vbd & WUFFS_BASE__TOKEN__VBD__NUMBER__FORMAT_TEXT) {\n            if (vbd & WUFFS_BASE__TOKEN__VBD__NUMBER__CONTENT_INTEGER_SIGNED) {\n              wuffs_base__result_i64 r = wuffs_base__parse_number_i64(\n                  wuffs_base__make_slice_u8(token_ptr, token_len),\n                  WUFFS_BASE__PARSE_NUMBER_XXX__DEFAULT_OPTIONS);\n              if (r.status.is_ok()) {\n                ret_error_message = callbacks.AppendI64(r.value);\n                goto parsed_a_value;\n              }\n            }\n            if (vbd & WUFFS_BASE__TOKEN__VBD__NUMBER__CONTENT_FLOATING_POINT) {\n              wuffs_base__result_f64 r = wuffs_base__parse_number_f64(\n                  wuffs_base__make_slice_u8(token_ptr, token_len),\n                  WUFFS_BASE__PARSE_NUMBER_XXX__DEFAULT_OPTIO" +
-	"NS);\n              if (r.status.is_ok()) {\n                ret_error_message = callbacks.AppendF64(r.value);\n                goto parsed_a_value;\n              }\n            }\n          } else if (vbd & WUFFS_BASE__TOKEN__VBD__NUMBER__CONTENT_NEG_INF) {\n            ret_error_message = callbacks.AppendF64(\n                wuffs_base__ieee_754_bit_representation__from_u64_to_f64(\n                    0xFFF0000000000000ul));\n            goto parsed_a_value;\n          } else if (vbd & WUFFS_BASE__TOKEN__VBD__NUMBER__CONTENT_POS_INF) {\n            ret_error_message = callbacks.AppendF64(\n                wuffs_base__ieee_754_bit_representation__from_u64_to_f64(\n                    0x7FF0000000000000ul));\n            goto parsed_a_value;\n          } else if (vbd & WUFFS_BASE__TOKEN__VBD__NUMBER__CONTENT_NEG_NAN) {\n            ret_error_message = callbacks.AppendF64(\n                wuffs_base__ieee_754_bit_representation__from_u64_to_f64(\n                    0xFFFFFFFFFFFFFFFFul));\n            goto parsed_a_value;\n  " +
-	"        } else if (vbd & WUFFS_BASE__TOKEN__VBD__NUMBER__CONTENT_POS_NAN) {\n            ret_error_message = callbacks.AppendF64(\n                wuffs_base__ieee_754_bit_representation__from_u64_to_f64(\n                    0x7FFFFFFFFFFFFFFFul));\n            goto parsed_a_value;\n          }\n        }\n      }\n\n    fail:\n      ret_error_message =\n          \"wuffs_aux::JsonDecoder: internal error: unexpected token\";\n      goto done;\n\n    parsed_a_value:\n      if (!ret_error_message.empty() || (depth == 0)) {\n        goto done;\n      }\n    }\n  } while (false);\n\ndone:\n  DecodeJsonResult result(\n      std::move(ret_error_message),\n      wuffs_base__u64__sat_add(io_buf->meta.pos, cursor_index));\n  callbacks.Done(result, input, *io_buf);\n  return result;\n}\n\n}  // namespace wuffs_aux\n\n#endif  // !defined(WUFFS_CONFIG__MODULES) ||\n        // defined(WUFFS_CONFIG__MODULE__AUX__JSON)\n" +
+	"// ---------------- Auxiliary - JSON\n\n#if !defined(WUFFS_CONFIG__MODULES) || defined(WUFFS_CONFIG__MODULE__AUX__JSON)\n\n#include <utility>\n\nnamespace wuffs_aux {\n\nDecodeJsonResult::DecodeJsonResult(std::string&& error_message0,\n                                   uint64_t cursor_position0)\n    : error_message(std::move(error_message0)),\n      cursor_position(cursor_position0) {}\n\nvoid DecodeJsonCallbacks::Done(DecodeJsonResult& result,\n                               sync_io::Input& input,\n                               IOBuffer& buffer) {}\n\nDecodeJsonResult  //\nDecodeJson(DecodeJsonCallbacks&& callbacks,\n           sync_io::Input&& input,\n           wuffs_base__slice_u32 quirks) {\n  // Prepare the wuffs_base__io_buffer and the resultant error_message.\n  wuffs_base__io_buffer* io_buf = input.BringsItsOwnIOBuffer();\n  wuffs_base__io_buffer fallback_io_buf = wuffs_base__empty_io_buffer();\n  std::unique_ptr<uint8_t[]> fallback_io_array(nullptr);\n  if (!io_buf) {\n    fallback_io_array = std::unique_ptr<uint8_t[]>(ne" +
+	"w uint8_t[4096]);\n    fallback_io_buf = wuffs_base__ptr_u8__writer(fallback_io_array.get(), 4096);\n    io_buf = &fallback_io_buf;\n  }\n  size_t cursor_index = 0;\n  std::string ret_error_message;\n  std::string io_error_message;\n\n  do {\n    // Prepare the low-level JSON decoder.\n    wuffs_json__decoder::unique_ptr dec = wuffs_json__decoder::alloc();\n    if (!dec) {\n      ret_error_message = \"wuffs_aux::JsonDecoder: out of memory\";\n      goto done;\n    }\n    for (size_t i = 0; i < quirks.len; i++) {\n      dec->set_quirk_enabled(quirks.ptr[i], true);\n    }\n\n    // Prepare the wuffs_base__tok_buffer.\n    wuffs_base__token tok_array[256];\n    wuffs_base__token_buffer tok_buf =\n        wuffs_base__slice_token__writer(wuffs_base__make_slice_token(\n            &tok_array[0], (sizeof(tok_array) / sizeof(tok_array[0]))));\n    wuffs_base__status tok_status = wuffs_base__make_status(nullptr);\n\n    // Prepare other state.\n    uint32_t depth = 0;\n    std::string str;\n\n    // Loop, doing these two things:\n    //  1. Get the n" +
+	"ext token.\n    //  2. Process that token.\n    while (true) {\n      // 1. Get the next token.\n\n      while (tok_buf.meta.ri >= tok_buf.meta.wi) {\n        if (tok_status.repr == nullptr) {\n          // No-op.\n        } else if (tok_status.repr == wuffs_base__suspension__short_write) {\n          tok_buf.compact();\n        } else if (tok_status.repr == wuffs_base__suspension__short_read) {\n          // Read from input to io_buf.\n          if (!io_error_message.empty()) {\n            ret_error_message = std::move(io_error_message);\n            goto done;\n          } else if (cursor_index != io_buf->meta.ri) {\n            ret_error_message =\n                \"wuffs_aux::JsonDecoder: internal error: bad cursor_index\";\n            goto done;\n          } else if (io_buf->meta.closed) {\n            ret_error_message =\n                \"wuffs_aux::JsonDecoder: internal error: io_buf is closed\";\n            goto done;\n          }\n          io_buf->compact();\n          if (io_buf->meta.wi >= io_buf->data.len) {\n            " +
+	"ret_error_message =\n                \"wuffs_aux::JsonDecoder: internal error: io_buf is full\";\n            goto done;\n          }\n          cursor_index = io_buf->meta.ri;\n          io_error_message = input.CopyIn(io_buf);\n        } else {\n          ret_error_message = tok_status.message();\n          goto done;\n        }\n\n        if (WUFFS_JSON__DECODER_WORKBUF_LEN_MAX_INCL_WORST_CASE != 0) {\n          ret_error_message =\n              \"wuffs_aux::JsonDecoder: internal error: bad WORKBUF_LEN\";\n          goto done;\n        }\n        wuffs_base__slice_u8 work_buf = wuffs_base__empty_slice_u8();\n        tok_status = dec->decode_tokens(&tok_buf, io_buf, work_buf);\n      }\n\n      wuffs_base__token token = tok_buf.data.ptr[tok_buf.meta.ri++];\n      uint64_t token_len = token.length();\n      if ((io_buf->meta.ri < cursor_index) ||\n          ((io_buf->meta.ri - cursor_index) < token_len)) {\n        ret_error_message =\n            \"wuffs_aux::JsonDecoder: internal error: bad token indexes\";\n        goto done;\n      }\n " +
+	"     uint8_t* token_ptr = io_buf->data.ptr + cursor_index;\n      cursor_index += token_len;\n\n      // 2. Process that token.\n\n      int64_t vbc = token.value_base_category();\n      uint64_t vbd = token.value_base_detail();\n      switch (vbc) {\n        case WUFFS_BASE__TOKEN__VBC__FILLER:\n          continue;\n\n        case WUFFS_BASE__TOKEN__VBC__STRUCTURE: {\n          if (vbd & WUFFS_BASE__TOKEN__VBD__STRUCTURE__PUSH) {\n            ret_error_message = callbacks.Push(static_cast<uint32_t>(vbd));\n            if (!ret_error_message.empty()) {\n              goto done;\n            }\n            depth++;\n            continue;\n          }\n          ret_error_message = callbacks.Pop(static_cast<uint32_t>(vbd));\n          depth--;\n          goto parsed_a_value;\n        }\n\n        case WUFFS_BASE__TOKEN__VBC__STRING: {\n          if (vbd & WUFFS_BASE__TOKEN__VBD__STRING__CONVERT_0_DST_1_SRC_DROP) {\n            // No-op.\n          } else if (vbd &\n                     WUFFS_BASE__TOKEN__VBD__STRING__CONVERT_1_DST_1_SRC_CO" +
+	"PY) {\n            const char* ptr =  // Convert from (uint8_t*).\n                static_cast<const char*>(static_cast<void*>(token_ptr));\n            str.append(ptr, token_len);\n          } else {\n            goto fail;\n          }\n          if (token.continued()) {\n            continue;\n          }\n          ret_error_message = callbacks.AppendTextString(std::move(str));\n          str.clear();\n          goto parsed_a_value;\n        }\n\n        case WUFFS_BASE__TOKEN__VBC__UNICODE_CODE_POINT: {\n          uint8_t u[WUFFS_BASE__UTF_8__BYTE_LENGTH__MAX_INCL];\n          size_t n = wuffs_base__utf_8__encode(\n              wuffs_base__make_slice_u8(\n                  &u[0], WUFFS_BASE__UTF_8__BYTE_LENGTH__MAX_INCL),\n              static_cast<uint32_t>(vbd));\n          const char* ptr =  // Convert from (uint8_t*).\n              static_cast<const char*>(static_cast<void*>(&u[0]));\n          str.append(ptr, n);\n          if (token.continued()) {\n            continue;\n          }\n          goto fail;\n        }\n\n       " +
+	" case WUFFS_BASE__TOKEN__VBC__LITERAL: {\n          ret_error_message =\n              (vbd & WUFFS_BASE__TOKEN__VBD__LITERAL__NULL)\n                  ? callbacks.AppendNull()\n                  : callbacks.AppendBool(vbd &\n                                         WUFFS_BASE__TOKEN__VBD__LITERAL__TRUE);\n          goto parsed_a_value;\n        }\n\n        case WUFFS_BASE__TOKEN__VBC__NUMBER: {\n          if (vbd & WUFFS_BASE__TOKEN__VBD__NUMBER__FORMAT_TEXT) {\n            if (vbd & WUFFS_BASE__TOKEN__VBD__NUMBER__CONTENT_INTEGER_SIGNED) {\n              wuffs_base__result_i64 r = wuffs_base__parse_number_i64(\n                  wuffs_base__make_slice_u8(token_ptr, token_len),\n                  WUFFS_BASE__PARSE_NUMBER_XXX__DEFAULT_OPTIONS);\n              if (r.status.is_ok()) {\n                ret_error_message = callbacks.AppendI64(r.value);\n                goto parsed_a_value;\n              }\n            }\n            if (vbd & WUFFS_BASE__TOKEN__VBD__NUMBER__CONTENT_FLOATING_POINT) {\n              wuffs_base__resul" +
+	"t_f64 r = wuffs_base__parse_number_f64(\n                  wuffs_base__make_slice_u8(token_ptr, token_len),\n                  WUFFS_BASE__PARSE_NUMBER_XXX__DEFAULT_OPTIONS);\n              if (r.status.is_ok()) {\n                ret_error_message = callbacks.AppendF64(r.value);\n                goto parsed_a_value;\n              }\n            }\n          } else if (vbd & WUFFS_BASE__TOKEN__VBD__NUMBER__CONTENT_NEG_INF) {\n            ret_error_message = callbacks.AppendF64(\n                wuffs_base__ieee_754_bit_representation__from_u64_to_f64(\n                    0xFFF0000000000000ul));\n            goto parsed_a_value;\n          } else if (vbd & WUFFS_BASE__TOKEN__VBD__NUMBER__CONTENT_POS_INF) {\n            ret_error_message = callbacks.AppendF64(\n                wuffs_base__ieee_754_bit_representation__from_u64_to_f64(\n                    0x7FF0000000000000ul));\n            goto parsed_a_value;\n          } else if (vbd & WUFFS_BASE__TOKEN__VBD__NUMBER__CONTENT_NEG_NAN) {\n            ret_error_message = callba" +
+	"cks.AppendF64(\n                wuffs_base__ieee_754_bit_representation__from_u64_to_f64(\n                    0xFFFFFFFFFFFFFFFFul));\n            goto parsed_a_value;\n          } else if (vbd & WUFFS_BASE__TOKEN__VBD__NUMBER__CONTENT_POS_NAN) {\n            ret_error_message = callbacks.AppendF64(\n                wuffs_base__ieee_754_bit_representation__from_u64_to_f64(\n                    0x7FFFFFFFFFFFFFFFul));\n            goto parsed_a_value;\n          }\n          goto fail;\n        }\n      }\n\n    fail:\n      ret_error_message =\n          \"wuffs_aux::JsonDecoder: internal error: unexpected token\";\n      goto done;\n\n    parsed_a_value:\n      if (!ret_error_message.empty() || (depth == 0)) {\n        goto done;\n      }\n    }\n  } while (false);\n\ndone:\n  DecodeJsonResult result(\n      std::move(ret_error_message),\n      wuffs_base__u64__sat_add(io_buf->meta.pos, cursor_index));\n  callbacks.Done(result, input, *io_buf);\n  return result;\n}\n\n}  // namespace wuffs_aux\n\n#endif  // !defined(WUFFS_CONFIG__MODULES) ||\n  " +
+	"      // defined(WUFFS_CONFIG__MODULE__AUX__JSON)\n" +
 	""
 
 const AuxJsonHh = "" +
-	"// ---------------- Auxiliary - JSON\n\nnamespace wuffs_aux {\n\nstruct DecodeJsonResult {\n  DecodeJsonResult(std::string&& error_message0, uint64_t cursor_position0);\n\n  std::string error_message;\n  uint64_t cursor_position;\n};\n\nclass DecodeJsonCallbacks {\n public:\n  // AppendXxx are called for leaf nodes: literals, numbers and strings. For\n  // strings, the Callbacks implementation is responsible for tracking map keys\n  // versus other values.\n\n  virtual std::string AppendNull() = 0;\n  virtual std::string AppendBool(bool val) = 0;\n  virtual std::string AppendI64(int64_t val) = 0;\n  virtual std::string AppendF64(double val) = 0;\n  virtual std::string AppendString(std::string&& val) = 0;\n\n  // Push and Pop are called for container nodes: JSON arrays (lists) and JSON\n  // objects (dictionaries).\n  //\n  // The flags bits combine exactly one of:\n  //  - WUFFS_BASE__TOKEN__VBD__STRUCTURE__FROM_NONE\n  //  - WUFFS_BASE__TOKEN__VBD__STRUCTURE__FROM_LIST\n  //  - WUFFS_BASE__TOKEN__VBD__STRUCTURE__FROM_DICT\n  // and exact" +
-	"ly one of:\n  //  - WUFFS_BASE__TOKEN__VBD__STRUCTURE__TO_NONE\n  //  - WUFFS_BASE__TOKEN__VBD__STRUCTURE__TO_LIST\n  //  - WUFFS_BASE__TOKEN__VBD__STRUCTURE__TO_DICT\n\n  virtual std::string Push(uint32_t flags) = 0;\n  virtual std::string Pop(uint32_t flags) = 0;\n\n  // Done is always the last Callback method called by DecodeJson, whether or\n  // not parsing the input as JSON encountered an error. Even when successful,\n  // trailing data may remain in input and buffer. See \"Unintuitive JSON\n  // Parsing\" (https://nullprogram.com/blog/2019/12/28/) which discusses JSON\n  // parsing and when it stops.\n  //\n  // Do not keep a reference to buffer or buffer.data.ptr after Done returns,\n  // as DecodeJson may then de-allocate the backing array.\n  virtual void Done(DecodeJsonResult& result,\n                    sync_io::Input& input,\n                    IOBuffer& buffer) = 0;\n};\n\n// DecodeJson calls callbacks based on the JSON-formatted data in input.\n//\n// On success, the returned error_message is empty and cursor_positio" +
+	"// ---------------- Auxiliary - JSON\n\nnamespace wuffs_aux {\n\nstruct DecodeJsonResult {\n  DecodeJsonResult(std::string&& error_message0, uint64_t cursor_position0);\n\n  std::string error_message;\n  uint64_t cursor_position;\n};\n\nclass DecodeJsonCallbacks {\n public:\n  // AppendXxx are called for leaf nodes: literals, numbers and strings. For\n  // strings, the Callbacks implementation is responsible for tracking map keys\n  // versus other values.\n\n  virtual std::string AppendNull() = 0;\n  virtual std::string AppendBool(bool val) = 0;\n  virtual std::string AppendF64(double val) = 0;\n  virtual std::string AppendI64(int64_t val) = 0;\n  virtual std::string AppendTextString(std::string&& val) = 0;\n\n  // Push and Pop are called for container nodes: JSON arrays (lists) and JSON\n  // objects (dictionaries).\n  //\n  // The flags bits combine exactly one of:\n  //  - WUFFS_BASE__TOKEN__VBD__STRUCTURE__FROM_NONE\n  //  - WUFFS_BASE__TOKEN__VBD__STRUCTURE__FROM_LIST\n  //  - WUFFS_BASE__TOKEN__VBD__STRUCTURE__FROM_DICT\n  // and e" +
+	"xactly one of:\n  //  - WUFFS_BASE__TOKEN__VBD__STRUCTURE__TO_NONE\n  //  - WUFFS_BASE__TOKEN__VBD__STRUCTURE__TO_LIST\n  //  - WUFFS_BASE__TOKEN__VBD__STRUCTURE__TO_DICT\n\n  virtual std::string Push(uint32_t flags) = 0;\n  virtual std::string Pop(uint32_t flags) = 0;\n\n  // Done is always the last Callback method called by DecodeJson, whether or\n  // not parsing the input as JSON encountered an error. Even when successful,\n  // trailing data may remain in input and buffer. See \"Unintuitive JSON\n  // Parsing\" (https://nullprogram.com/blog/2019/12/28/) which discusses JSON\n  // parsing and when it stops.\n  //\n  // Do not keep a reference to buffer or buffer.data.ptr after Done returns,\n  // as DecodeJson may then de-allocate the backing array.\n  virtual void Done(DecodeJsonResult& result,\n                    sync_io::Input& input,\n                    IOBuffer& buffer);\n};\n\n// DecodeJson calls callbacks based on the JSON-formatted data in input.\n//\n// On success, the returned error_message is empty and cursor_positio" +
 	"n counts\n// the number of bytes consumed. On failure, error_message is non-empty and\n// cursor_position is the location of the error. That error may be a content\n// error (invalid JSON) or an input error (e.g. network failure).\nDecodeJsonResult DecodeJson(DecodeJsonCallbacks&& callbacks,\n                            sync_io::Input&& input,\n                            wuffs_base__slice_u32 quirks);\n\n}  // namespace wuffs_aux\n" +
 	""
 
diff --git a/release/c/wuffs-unsupported-snapshot.c b/release/c/wuffs-unsupported-snapshot.c
index b0a2fb1..781b156 100644
--- a/release/c/wuffs-unsupported-snapshot.c
+++ b/release/c/wuffs-unsupported-snapshot.c
@@ -8495,9 +8495,9 @@
 
   virtual std::string AppendNull() = 0;
   virtual std::string AppendBool(bool val) = 0;
-  virtual std::string AppendI64(int64_t val) = 0;
   virtual std::string AppendF64(double val) = 0;
-  virtual std::string AppendString(std::string&& val) = 0;
+  virtual std::string AppendI64(int64_t val) = 0;
+  virtual std::string AppendTextString(std::string&& val) = 0;
 
   // Push and Pop are called for container nodes: JSON arrays (lists) and JSON
   // objects (dictionaries).
@@ -8524,7 +8524,7 @@
   // as DecodeJson may then de-allocate the backing array.
   virtual void Done(DecodeJsonResult& result,
                     sync_io::Input& input,
-                    IOBuffer& buffer) = 0;
+                    IOBuffer& buffer);
 };
 
 // DecodeJson calls callbacks based on the JSON-formatted data in input.
@@ -29267,6 +29267,10 @@
     : error_message(std::move(error_message0)),
       cursor_position(cursor_position0) {}
 
+void DecodeJsonCallbacks::Done(DecodeJsonResult& result,
+                               sync_io::Input& input,
+                               IOBuffer& buffer) {}
+
 DecodeJsonResult  //
 DecodeJson(DecodeJsonCallbacks&& callbacks,
            sync_io::Input&& input,
@@ -29400,7 +29404,7 @@
           if (token.continued()) {
             continue;
           }
-          ret_error_message = callbacks.AppendString(std::move(str));
+          ret_error_message = callbacks.AppendTextString(std::move(str));
           str.clear();
           goto parsed_a_value;
         }
@@ -29470,6 +29474,7 @@
                     0x7FFFFFFFFFFFFFFFul));
             goto parsed_a_value;
           }
+          goto fail;
         }
       }