diff --git a/js/src/frontend/BytecodeEmitter.cpp b/js/src/frontend/BytecodeEmitter.cpp
index df1b44a63eb6..643fa72b4482 100644
--- a/js/src/frontend/BytecodeEmitter.cpp
+++ b/js/src/frontend/BytecodeEmitter.cpp
@@ -2141,7 +2141,7 @@ class ForOfLoopControl : public LoopControl
 };
 
 BytecodeEmitter::BytecodeEmitter(BytecodeEmitter* parent,
-                                 const EitherParser<FullParseHandler>& parser, SharedContext* sc,
+                                 const EitherParser& parser, SharedContext* sc,
                                  HandleScript script, Handle<LazyScript*> lazyScript,
                                  uint32_t lineNum, EmitterMode emitterMode)
   : sc(sc),
@@ -2181,7 +2181,7 @@ BytecodeEmitter::BytecodeEmitter(BytecodeEmitter* parent,
 }
 
 BytecodeEmitter::BytecodeEmitter(BytecodeEmitter* parent,
-                                 const EitherParser<FullParseHandler>& parser, SharedContext* sc,
+                                 const EitherParser& parser, SharedContext* sc,
                                  HandleScript script, Handle<LazyScript*> lazyScript,
                                  TokenPos bodyPosition, EmitterMode emitterMode)
     : BytecodeEmitter(parent, parser, sc, script, lazyScript,
diff --git a/js/src/frontend/BytecodeEmitter.h b/js/src/frontend/BytecodeEmitter.h
index 4fcc751fd86e..883779dfba3c 100644
--- a/js/src/frontend/BytecodeEmitter.h
+++ b/js/src/frontend/BytecodeEmitter.h
@@ -220,7 +220,7 @@ struct MOZ_STACK_CLASS BytecodeEmitter
     };
     EmitSection prologue, main, *current;
 
-    EitherParser<FullParseHandler> parser;
+    EitherParser parser;
 
     PooledMapPtr<AtomIndexMap> atomIndices; /* literals indexed for mapping */
     unsigned        firstLine;      /* first line, for JSScript::initFromEmitter */
@@ -295,7 +295,7 @@ struct MOZ_STACK_CLASS BytecodeEmitter
      * tempLifoAlloc and save the pointer beyond the next BytecodeEmitter
      * destruction.
      */
-    BytecodeEmitter(BytecodeEmitter* parent, const EitherParser<FullParseHandler>& parser,
+    BytecodeEmitter(BytecodeEmitter* parent, const EitherParser& parser,
                     SharedContext* sc, HandleScript script, Handle<LazyScript*> lazyScript,
                     uint32_t lineNum, EmitterMode emitterMode = Normal);
 
@@ -303,13 +303,13 @@ struct MOZ_STACK_CLASS BytecodeEmitter
     BytecodeEmitter(BytecodeEmitter* parent, Parser<FullParseHandler, CharT>* parser,
                     SharedContext* sc, HandleScript script, Handle<LazyScript*> lazyScript,
                     uint32_t lineNum, EmitterMode emitterMode = Normal)
-      : BytecodeEmitter(parent, EitherParser<FullParseHandler>(parser), sc, script, lazyScript,
+      : BytecodeEmitter(parent, EitherParser(parser), sc, script, lazyScript,
                         lineNum, emitterMode)
     {}
 
     // An alternate constructor that uses a TokenPos for the starting
     // line and that sets functionBodyEndPos as well.
-    BytecodeEmitter(BytecodeEmitter* parent, const EitherParser<FullParseHandler>& parser,
+    BytecodeEmitter(BytecodeEmitter* parent, const EitherParser& parser,
                     SharedContext* sc, HandleScript script, Handle<LazyScript*> lazyScript,
                     TokenPos bodyPosition, EmitterMode emitterMode = Normal);
 
@@ -317,7 +317,7 @@ struct MOZ_STACK_CLASS BytecodeEmitter
     BytecodeEmitter(BytecodeEmitter* parent, Parser<FullParseHandler, CharT>* parser,
                     SharedContext* sc, HandleScript script, Handle<LazyScript*> lazyScript,
                     TokenPos bodyPosition, EmitterMode emitterMode = Normal)
-      : BytecodeEmitter(parent, EitherParser<FullParseHandler>(parser), sc, script, lazyScript,
+      : BytecodeEmitter(parent, EitherParser(parser), sc, script, lazyScript,
                         bodyPosition, emitterMode)
     {}
 
diff --git a/js/src/frontend/EitherParser.h b/js/src/frontend/EitherParser.h
index 2d9a85c11702..913f3795f872 100644
--- a/js/src/frontend/EitherParser.h
+++ b/js/src/frontend/EitherParser.h
@@ -70,7 +70,7 @@ struct GetParser
 template<class Parser>
 struct GetParseHandler
 {
-    static auto get(Parser* parser) -> decltype(&parser->handler) {
+    static frontend::FullParseHandler* get(Parser* parser) {
         return &parser->handler;
     }
 };
@@ -147,12 +147,12 @@ struct ErrorReporterMatcher
 
 namespace frontend {
 
-template<class ParseHandler>
 class EitherParser
 {
-    mozilla::Variant<Parser<ParseHandler, char16_t>* const> parser;
+    // Leave this as a variant, to promote good form until 8-bit parser integration.
+    mozilla::Variant<Parser<FullParseHandler, char16_t>* const> parser;
 
-    using Node = typename ParseHandler::Node;
+    using Node = typename FullParseHandler::Node;
 
     template<template <class Parser> class GetThis,
              template <class This> class GetMemberFunction,