[NFC] Simplify `Tuple` by making it an alias of `TypeList` (#5775)

Rather than wrap a `TypeList`, make `Tuple` an alias of `TypeList`. This means
removing `Tuple::toString`, but that had no callers and was of limited use for
debugging anyway. In return, the use of tuples becomes much less verbose.

In the future, it may make sense to remove one of `Tuple` and `TypeList`.

1 files changed, 3 insertions, 30 deletions

diff --git a/src/wasm-type.h b/src/wasm-type.h
index 095186c3c..a8a331ace 100644
--- a/src/wasm-type.h
+++ b/src/wasm-type.h
@@ -51,12 +51,14 @@ void destroyAllTypesForTestingPurposesOnly();
 class Type;
 class HeapType;
 class RecGroup;
-struct Tuple;
 struct Signature;
 struct Field;
 struct Struct;
 struct Array;
 
+using TypeList = std::vector<Type>;
+using Tuple = TypeList;
+
 enum Nullability { NonNullable, Nullable };
 enum Mutability { Immutable, Mutable };
 
@@ -453,31 +455,6 @@ public:
   HeapType operator[](size_t i) const { return *Iterator{{this, i}}; }
 };
 
-using TypeList = std::vector<Type>;
-
-// Passed by reference rather than by value because it can own an unbounded
-// amount of data.
-struct Tuple {
-  TypeList types;
-  Tuple() : types() {}
-  Tuple(std::initializer_list<Type> types) : types(types) { validate(); }
-  Tuple(const TypeList& types) : types(types) { validate(); }
-  Tuple(TypeList&& types) : types(std::move(types)) { validate(); }
-
-  bool operator==(const Tuple& other) const { return types == other.types; }
-  bool operator!=(const Tuple& other) const { return !(*this == other); }
-  std::string toString() const;
-
-private:
-  void validate() {
-#ifndef NDEBUG
-    for (auto type : types) {
-      assert(type.isSingle());
-    }
-#endif
-  }
-};
-
 struct Signature {
   Type params;
   Type results;
@@ -692,10 +669,6 @@ template<> class hash<wasm::Type> {
 public:
   size_t operator()(const wasm::Type&) const;
 };
-template<> class hash<wasm::Tuple> {
-public:
-  size_t operator()(const wasm::Tuple&) const;
-};
 template<> class hash<wasm::Signature> {
 public:
   size_t operator()(const wasm::Signature&) const;