diff --git a/src/ast/access_decoration.cc b/src/ast/access_decoration.cc
index 18d0d6e06b..a22b99bad3 100644
--- a/src/ast/access_decoration.cc
+++ b/src/ast/access_decoration.cc
@@ -28,10 +28,6 @@ DecorationKind AccessDecoration::GetKind() const {
   return Kind;
 }
 
-bool AccessDecoration::IsKind(DecorationKind kind) const {
-  return kind == Kind || Base::IsKind(kind);
-}
-
 bool AccessDecoration::IsAccess() const {
   return true;
 }
diff --git a/src/ast/access_decoration.h b/src/ast/access_decoration.h
index 489c0e9bbe..41baa63e66 100644
--- a/src/ast/access_decoration.h
+++ b/src/ast/access_decoration.h
@@ -38,11 +38,6 @@ class AccessDecoration : public Castable<AccessDecoration, TypeDecoration> {
   /// @return the decoration kind
   DecorationKind GetKind() const override;
 
-  /// @param kind the decoration kind
-  /// @return true if this Decoration is of the (or derives from) the given
-  /// kind.
-  bool IsKind(DecorationKind kind) const override;
-
   /// @returns true if this is an access decoration
   bool IsAccess() const override;
 
diff --git a/src/ast/array_decoration.cc b/src/ast/array_decoration.cc
index 088a87f474..62338b27e1 100644
--- a/src/ast/array_decoration.cc
+++ b/src/ast/array_decoration.cc
@@ -31,10 +31,6 @@ DecorationKind ArrayDecoration::GetKind() const {
   return Kind;
 }
 
-bool ArrayDecoration::IsKind(DecorationKind kind) const {
-  return kind == Kind;
-}
-
 bool ArrayDecoration::IsStride() const {
   return false;
 }
diff --git a/src/ast/array_decoration.h b/src/ast/array_decoration.h
index 92cb00282e..43141a0034 100644
--- a/src/ast/array_decoration.h
+++ b/src/ast/array_decoration.h
@@ -37,11 +37,6 @@ class ArrayDecoration : public Castable<ArrayDecoration, Decoration> {
   /// @return the decoration kind
   DecorationKind GetKind() const override;
 
-  /// @param kind the decoration kind
-  /// @return true if this Decoration is of the (or derives from) the given
-  /// kind.
-  bool IsKind(DecorationKind kind) const override;
-
   /// @returns true if this is a stride decoration
   virtual bool IsStride() const;
 
diff --git a/src/ast/binding_decoration.cc b/src/ast/binding_decoration.cc
index 671e319d3b..73f3836a3f 100644
--- a/src/ast/binding_decoration.cc
+++ b/src/ast/binding_decoration.cc
@@ -28,10 +28,6 @@ DecorationKind BindingDecoration::GetKind() const {
   return Kind;
 }
 
-bool BindingDecoration::IsKind(DecorationKind kind) const {
-  return kind == Kind || Base::IsKind(kind);
-}
-
 bool BindingDecoration::IsBinding() const {
   return true;
 }
diff --git a/src/ast/binding_decoration.h b/src/ast/binding_decoration.h
index e747edc7fd..8799656531 100644
--- a/src/ast/binding_decoration.h
+++ b/src/ast/binding_decoration.h
@@ -38,11 +38,6 @@ class BindingDecoration
   /// @return the decoration kind
   DecorationKind GetKind() const override;
 
-  /// @param kind the decoration kind
-  /// @return true if this Decoration is of the (or derives from) the given
-  /// kind.
-  bool IsKind(DecorationKind kind) const override;
-
   /// @returns true if this is a binding decoration
   bool IsBinding() const override;
 
diff --git a/src/ast/builtin_decoration.cc b/src/ast/builtin_decoration.cc
index e59b592f14..a6202905d5 100644
--- a/src/ast/builtin_decoration.cc
+++ b/src/ast/builtin_decoration.cc
@@ -28,10 +28,6 @@ DecorationKind BuiltinDecoration::GetKind() const {
   return Kind;
 }
 
-bool BuiltinDecoration::IsKind(DecorationKind kind) const {
-  return kind == Kind || Base::IsKind(kind);
-}
-
 bool BuiltinDecoration::IsBuiltin() const {
   return true;
 }
diff --git a/src/ast/builtin_decoration.h b/src/ast/builtin_decoration.h
index cc0dc6d5ab..4aaf215b09 100644
--- a/src/ast/builtin_decoration.h
+++ b/src/ast/builtin_decoration.h
@@ -37,11 +37,6 @@ class BuiltinDecoration
   /// @return the decoration kind
   DecorationKind GetKind() const override;
 
-  /// @param kind the decoration kind
-  /// @return true if this Decoration is of the (or derives from) the given
-  /// kind.
-  bool IsKind(DecorationKind kind) const override;
-
   /// @returns true if this is a builtin decoration
   bool IsBuiltin() const override;
 
diff --git a/src/ast/constant_id_decoration.cc b/src/ast/constant_id_decoration.cc
index 7b1bc534df..405d06418d 100644
--- a/src/ast/constant_id_decoration.cc
+++ b/src/ast/constant_id_decoration.cc
@@ -28,10 +28,6 @@ DecorationKind ConstantIdDecoration::GetKind() const {
   return Kind;
 }
 
-bool ConstantIdDecoration::IsKind(DecorationKind kind) const {
-  return kind == Kind || Base::IsKind(kind);
-}
-
 bool ConstantIdDecoration::IsConstantId() const {
   return true;
 }
diff --git a/src/ast/constant_id_decoration.h b/src/ast/constant_id_decoration.h
index cc260cf5b5..ec8512c002 100644
--- a/src/ast/constant_id_decoration.h
+++ b/src/ast/constant_id_decoration.h
@@ -37,11 +37,6 @@ class ConstantIdDecoration
   /// @return the decoration kind
   DecorationKind GetKind() const override;
 
-  /// @param kind the decoration kind
-  /// @return true if this Decoration is of the (or derives from) the given
-  /// kind.
-  bool IsKind(DecorationKind kind) const override;
-
   /// @returns true if this is a constant_id decoration
   bool IsConstantId() const override;
 
diff --git a/src/ast/decoration.h b/src/ast/decoration.h
index bf30452b80..69e3287645 100644
--- a/src/ast/decoration.h
+++ b/src/ast/decoration.h
@@ -54,11 +54,6 @@ class Decoration : public Castable<Decoration, Node> {
   /// @return the decoration kind
   virtual DecorationKind GetKind() const = 0;
 
-  /// @param kind the decoration kind
-  /// @return true if this Decoration is of the (or derives from) the given
-  /// kind.
-  virtual bool IsKind(DecorationKind kind) const = 0;
-
   /// @returns true if the node is valid
   bool IsValid() const override;
 
@@ -68,19 +63,6 @@ class Decoration : public Castable<Decoration, Node> {
   explicit Decoration(const Source& source) : Base(source) {}
 };
 
-/// As dynamically casts |deco| to the target type |TO|.
-/// @return the cast decoration, or nullptr if |deco| is not of the type |TO|.
-template <typename TO>
-TO* As(Decoration* deco) {
-  if (deco == nullptr) {
-    return nullptr;
-  }
-  if (deco->Is<TO>()) {
-    return static_cast<TO*>(deco);
-  }
-  return nullptr;
-}
-
 /// A list of decorations
 using DecorationList = std::vector<Decoration*>;
 
diff --git a/src/ast/decoration_test.cc b/src/ast/decoration_test.cc
index 1df9f9cf89..d5149795f0 100644
--- a/src/ast/decoration_test.cc
+++ b/src/ast/decoration_test.cc
@@ -81,112 +81,6 @@ TEST_F(DecorationTest, Kinds) {
   EXPECT_EQ(LocationDecoration::Kind, DecorationKind::kLocation);
 }
 
-TEST_F(DecorationTest, IsKind) {
-  std::vector<DecorationKind> all_kinds{
-      DecorationKind::kArray,        DecorationKind::kStride,
-      DecorationKind::kFunction,     DecorationKind::kStage,
-      DecorationKind::kWorkgroup,    DecorationKind::kStruct,
-      DecorationKind::kStructMember, DecorationKind::kStructMemberOffset,
-      DecorationKind::kType,         DecorationKind::kAccess,
-      DecorationKind::kVariable,     DecorationKind::kBinding,
-      DecorationKind::kBuiltin,      DecorationKind::kConstantId,
-      DecorationKind::kLocation,
-  };
-
-  struct ExpectedKinds {
-    DecorationKind kind;
-    std::unordered_set<DecorationKind> expect_true;
-  };
-
-  //  kArray
-  //   | kStride
-  //  kFunction
-  //   | kStage
-  //   | kWorkgroup
-  //  kStruct
-  //  kStructMember
-  //   | kStructMemberOffset
-  //  kType
-  //   | kAccess
-  //  kVariable
-  //   | kBinding
-  //   | kBuiltin
-  //   | kConstantId
-  //   | kLocation
-  std::unordered_map<DecorationKind, std::unordered_set<DecorationKind>>
-      kind_is{
-          {
-              DecorationKind::kStride,
-              {DecorationKind::kArray, DecorationKind::kStride},
-          },
-          {
-              DecorationKind::kStage,
-              {DecorationKind::kFunction, DecorationKind::kStage},
-          },
-          {
-              DecorationKind::kWorkgroup,
-              {DecorationKind::kFunction, DecorationKind::kWorkgroup},
-          },
-          {
-              DecorationKind::kStruct,
-              {DecorationKind::kStruct},
-          },
-          {
-              DecorationKind::kStructMemberOffset,
-              {DecorationKind::kStructMember,
-               DecorationKind::kStructMemberOffset},
-          },
-          {
-              DecorationKind::kAccess,
-              {DecorationKind::kType, DecorationKind::kAccess},
-          },
-          {
-              DecorationKind::kBinding,
-              {DecorationKind::kVariable, DecorationKind::kBinding},
-          },
-          {
-              DecorationKind::kBuiltin,
-              {DecorationKind::kVariable, DecorationKind::kBuiltin},
-          },
-          {
-              DecorationKind::kConstantId,
-              {DecorationKind::kVariable, DecorationKind::kConstantId},
-          },
-          {
-              DecorationKind::kLocation,
-              {DecorationKind::kVariable, DecorationKind::kLocation},
-          },
-      };
-
-  auto check = [&](Decoration* d) {
-    auto& is_set = kind_is[d->GetKind()];
-    for (auto test : all_kinds) {
-      bool is_kind = is_set.find(test) != is_set.end();
-      EXPECT_EQ(d->IsKind(test), is_kind)
-          << "decoration: " << d->GetKind() << " IsKind(" << test << ")";
-    }
-  };
-  StrideDecoration stride(0, {});
-  StageDecoration stage(PipelineStage::kNone, {});
-  WorkgroupDecoration workgroup(0, {});
-  StructMemberOffsetDecoration struct_member_offset(0, {});
-  AccessDecoration access(AccessControl::kReadOnly, {});
-  BindingDecoration binding(0, {});
-  BuiltinDecoration builtin(Builtin::kNone, {});
-  ConstantIdDecoration constant_id(0, {});
-  LocationDecoration location(0, {});
-
-  check(&stride);
-  check(&stage);
-  check(&workgroup);
-  check(&struct_member_offset);
-  check(&access);
-  check(&binding);
-  check(&builtin);
-  check(&constant_id);
-  check(&location);
-}
-
 }  // namespace
 }  // namespace ast
 }  // namespace tint
diff --git a/src/ast/function_decoration.cc b/src/ast/function_decoration.cc
index 36861c4093..2f8fe6fa77 100644
--- a/src/ast/function_decoration.cc
+++ b/src/ast/function_decoration.cc
@@ -32,10 +32,6 @@ DecorationKind FunctionDecoration::GetKind() const {
   return Kind;
 }
 
-bool FunctionDecoration::IsKind(DecorationKind kind) const {
-  return kind == Kind;
-}
-
 bool FunctionDecoration::IsStage() const {
   return false;
 }
diff --git a/src/ast/function_decoration.h b/src/ast/function_decoration.h
index 5c15a6cee3..4fb50ab413 100644
--- a/src/ast/function_decoration.h
+++ b/src/ast/function_decoration.h
@@ -38,11 +38,6 @@ class FunctionDecoration : public Castable<FunctionDecoration, Decoration> {
   /// @return the decoration kind
   DecorationKind GetKind() const override;
 
-  /// @param kind the decoration kind
-  /// @return true if this Decoration is of the (or derives from) the given
-  /// kind.
-  bool IsKind(DecorationKind kind) const override;
-
   /// @returns true if this is a stage decoration
   virtual bool IsStage() const;
   /// @returns true if this is a workgroup decoration
diff --git a/src/ast/location_decoration.cc b/src/ast/location_decoration.cc
index 1ca0e39271..bc0c625f27 100644
--- a/src/ast/location_decoration.cc
+++ b/src/ast/location_decoration.cc
@@ -28,10 +28,6 @@ DecorationKind LocationDecoration::GetKind() const {
   return Kind;
 }
 
-bool LocationDecoration::IsKind(DecorationKind kind) const {
-  return kind == Kind || Base::IsKind(kind);
-}
-
 bool LocationDecoration::IsLocation() const {
   return true;
 }
diff --git a/src/ast/location_decoration.h b/src/ast/location_decoration.h
index c99267d16a..2d1d029a63 100644
--- a/src/ast/location_decoration.h
+++ b/src/ast/location_decoration.h
@@ -38,11 +38,6 @@ class LocationDecoration
   /// @return the decoration kind
   DecorationKind GetKind() const override;
 
-  /// @param kind the decoration kind
-  /// @return true if this Decoration is of the (or derives from) the given
-  /// kind.
-  bool IsKind(DecorationKind kind) const override;
-
   /// @returns true if this is a location decoration
   bool IsLocation() const override;
 
diff --git a/src/ast/stage_decoration.cc b/src/ast/stage_decoration.cc
index 307503ba9d..da0f52b276 100644
--- a/src/ast/stage_decoration.cc
+++ b/src/ast/stage_decoration.cc
@@ -28,10 +28,6 @@ DecorationKind StageDecoration::GetKind() const {
   return Kind;
 }
 
-bool StageDecoration::IsKind(DecorationKind kind) const {
-  return kind == Kind || Base::IsKind(kind);
-}
-
 bool StageDecoration::IsStage() const {
   return true;
 }
diff --git a/src/ast/stage_decoration.h b/src/ast/stage_decoration.h
index 15b1d60485..15d7490f6b 100644
--- a/src/ast/stage_decoration.h
+++ b/src/ast/stage_decoration.h
@@ -36,11 +36,6 @@ class StageDecoration : public Castable<StageDecoration, FunctionDecoration> {
   /// @return the decoration kind
   DecorationKind GetKind() const override;
 
-  /// @param kind the decoration kind
-  /// @return true if this Decoration is of the (or derives from) the given
-  /// kind.
-  bool IsKind(DecorationKind kind) const override;
-
   /// @returns true if this is a stage decoration
   bool IsStage() const override;
 
diff --git a/src/ast/stride_decoration.cc b/src/ast/stride_decoration.cc
index 8e30f3c9c7..a0b2c4e515 100644
--- a/src/ast/stride_decoration.cc
+++ b/src/ast/stride_decoration.cc
@@ -26,10 +26,6 @@ DecorationKind StrideDecoration::GetKind() const {
   return Kind;
 }
 
-bool StrideDecoration::IsKind(DecorationKind kind) const {
-  return kind == Kind || Base::IsKind(kind);
-}
-
 bool StrideDecoration::IsStride() const {
   return true;
 }
diff --git a/src/ast/stride_decoration.h b/src/ast/stride_decoration.h
index a64754a2cf..84acdd3b1f 100644
--- a/src/ast/stride_decoration.h
+++ b/src/ast/stride_decoration.h
@@ -39,11 +39,6 @@ class StrideDecoration : public Castable<StrideDecoration, ArrayDecoration> {
   /// @return the decoration kind
   DecorationKind GetKind() const override;
 
-  /// @param kind the decoration kind
-  /// @return true if this Decoration is of the (or derives from) the given
-  /// kind.
-  bool IsKind(DecorationKind kind) const override;
-
   /// @returns true if this is a stride decoration
   bool IsStride() const override;
 
diff --git a/src/ast/struct_decoration.cc b/src/ast/struct_decoration.cc
index 68b54a4394..4b372fd2d9 100644
--- a/src/ast/struct_decoration.cc
+++ b/src/ast/struct_decoration.cc
@@ -27,9 +27,5 @@ DecorationKind StructDecoration::GetKind() const {
   return Kind;
 }
 
-bool StructDecoration::IsKind(DecorationKind kind) const {
-  return kind == Kind;
-}
-
 }  // namespace ast
 }  // namespace tint
diff --git a/src/ast/struct_decoration.h b/src/ast/struct_decoration.h
index 75d3e69a82..bba2162d2a 100644
--- a/src/ast/struct_decoration.h
+++ b/src/ast/struct_decoration.h
@@ -35,11 +35,6 @@ class StructDecoration : public Castable<StructDecoration, Decoration> {
   /// @return the decoration kind
   DecorationKind GetKind() const override;
 
-  /// @param kind the decoration kind
-  /// @return true if this Decoration is of the (or derives from) the given
-  /// kind.
-  bool IsKind(DecorationKind kind) const override;
-
   /// @returns true if this is a block struct
   virtual bool IsBlock() const = 0;
 
diff --git a/src/ast/struct_member_decoration.cc b/src/ast/struct_member_decoration.cc
index b56ec520c1..9c3118d9ce 100644
--- a/src/ast/struct_member_decoration.cc
+++ b/src/ast/struct_member_decoration.cc
@@ -32,10 +32,6 @@ DecorationKind StructMemberDecoration::GetKind() const {
   return Kind;
 }
 
-bool StructMemberDecoration::IsKind(DecorationKind kind) const {
-  return kind == Kind;
-}
-
 bool StructMemberDecoration::IsOffset() const {
   return false;
 }
diff --git a/src/ast/struct_member_decoration.h b/src/ast/struct_member_decoration.h
index 2c1400a9c7..837ecc0756 100644
--- a/src/ast/struct_member_decoration.h
+++ b/src/ast/struct_member_decoration.h
@@ -38,11 +38,6 @@ class StructMemberDecoration
   /// @return the decoration kind
   DecorationKind GetKind() const override;
 
-  /// @param kind the decoration kind
-  /// @return true if this Decoration is of the (or derives from) the given
-  /// kind.
-  bool IsKind(DecorationKind kind) const override;
-
   /// @returns true if this is an offset decoration
   virtual bool IsOffset() const;
 
diff --git a/src/ast/struct_member_offset_decoration.cc b/src/ast/struct_member_offset_decoration.cc
index 24366584e1..9ded0faff0 100644
--- a/src/ast/struct_member_offset_decoration.cc
+++ b/src/ast/struct_member_offset_decoration.cc
@@ -27,10 +27,6 @@ DecorationKind StructMemberOffsetDecoration::GetKind() const {
   return Kind;
 }
 
-bool StructMemberOffsetDecoration::IsKind(DecorationKind kind) const {
-  return kind == Kind || Base::IsKind(kind);
-}
-
 bool StructMemberOffsetDecoration::IsOffset() const {
   return true;
 }
diff --git a/src/ast/struct_member_offset_decoration.h b/src/ast/struct_member_offset_decoration.h
index 531336df82..e0f015cb1d 100644
--- a/src/ast/struct_member_offset_decoration.h
+++ b/src/ast/struct_member_offset_decoration.h
@@ -41,11 +41,6 @@ class StructMemberOffsetDecoration
   /// @return the decoration kind
   DecorationKind GetKind() const override;
 
-  /// @param kind the decoration kind
-  /// @return true if this Decoration is of the (or derives from) the given
-  /// kind.
-  bool IsKind(DecorationKind kind) const override;
-
   /// @returns true if this is an offset decoration
   bool IsOffset() const override;
 
diff --git a/src/ast/type_decoration.cc b/src/ast/type_decoration.cc
index 3f08e1a43d..84f9e5f3ba 100644
--- a/src/ast/type_decoration.cc
+++ b/src/ast/type_decoration.cc
@@ -31,10 +31,6 @@ DecorationKind TypeDecoration::GetKind() const {
   return Kind;
 }
 
-bool TypeDecoration::IsKind(DecorationKind kind) const {
-  return kind == Kind;
-}
-
 bool TypeDecoration::IsAccess() const {
   return false;
 }
diff --git a/src/ast/type_decoration.h b/src/ast/type_decoration.h
index 7b962184dc..987cc9c2c1 100644
--- a/src/ast/type_decoration.h
+++ b/src/ast/type_decoration.h
@@ -38,11 +38,6 @@ class TypeDecoration : public Castable<TypeDecoration, Decoration> {
   /// @return the decoration kind
   DecorationKind GetKind() const override;
 
-  /// @param kind the decoration kind
-  /// @return true if this Decoration is of the (or derives from) the given
-  /// kind.
-  bool IsKind(DecorationKind kind) const override;
-
   /// @returns true if this is an access decoration
   virtual bool IsAccess() const;
 
diff --git a/src/ast/variable_decoration.cc b/src/ast/variable_decoration.cc
index 84ed238558..a3e605d1f2 100644
--- a/src/ast/variable_decoration.cc
+++ b/src/ast/variable_decoration.cc
@@ -35,10 +35,6 @@ DecorationKind VariableDecoration::GetKind() const {
   return Kind;
 }
 
-bool VariableDecoration::IsKind(DecorationKind kind) const {
-  return kind == Kind;
-}
-
 bool VariableDecoration::IsBinding() const {
   return false;
 }
diff --git a/src/ast/variable_decoration.h b/src/ast/variable_decoration.h
index 8fd4e44def..7dc1bc8bb7 100644
--- a/src/ast/variable_decoration.h
+++ b/src/ast/variable_decoration.h
@@ -42,11 +42,6 @@ class VariableDecoration : public Castable<VariableDecoration, Decoration> {
   /// @return the decoration kind
   DecorationKind GetKind() const override;
 
-  /// @param kind the decoration kind
-  /// @return true if this Decoration is of the (or derives from) the given
-  /// kind.
-  bool IsKind(DecorationKind kind) const override;
-
   /// @returns true if this is a binding decoration
   virtual bool IsBinding() const;
   /// @returns true if this is a builtin decoration
diff --git a/src/ast/workgroup_decoration.cc b/src/ast/workgroup_decoration.cc
index 045143bd08..1d3040169a 100644
--- a/src/ast/workgroup_decoration.cc
+++ b/src/ast/workgroup_decoration.cc
@@ -39,10 +39,6 @@ DecorationKind WorkgroupDecoration::GetKind() const {
   return Kind;
 }
 
-bool WorkgroupDecoration::IsKind(DecorationKind kind) const {
-  return kind == Kind || Base::IsKind(kind);
-}
-
 bool WorkgroupDecoration::IsWorkgroup() const {
   return true;
 }
diff --git a/src/ast/workgroup_decoration.h b/src/ast/workgroup_decoration.h
index 41c690ccb2..bc6bd99fa7 100644
--- a/src/ast/workgroup_decoration.h
+++ b/src/ast/workgroup_decoration.h
@@ -51,11 +51,6 @@ class WorkgroupDecoration
   /// @return the decoration kind
   DecorationKind GetKind() const override;
 
-  /// @param kind the decoration kind
-  /// @return true if this Decoration is of the (or derives from) the given
-  /// kind.
-  bool IsKind(DecorationKind kind) const override;
-
   /// @returns true if this is a workgroup decoration
   bool IsWorkgroup() const override;
 
diff --git a/src/reader/wgsl/parser_impl.cc b/src/reader/wgsl/parser_impl.cc
index 11ef56a0f3..675c2fecba 100644
--- a/src/reader/wgsl/parser_impl.cc
+++ b/src/reader/wgsl/parser_impl.cc
@@ -2895,7 +2895,7 @@ std::vector<T*> ParserImpl::take_decorations(ast::DecorationList& in) {
   out.reserve(in.size());
   for (auto* deco : in) {
     if (deco->Is<T>()) {
-      out.emplace_back(ast::As<T>(deco));
+      out.emplace_back(deco->As<T>());
     } else {
       remaining.emplace_back(deco);
     }
diff --git a/src/reader/wgsl/parser_impl_function_decoration_list_test.cc b/src/reader/wgsl/parser_impl_function_decoration_list_test.cc
index 9a7da60c48..c77e78371e 100644
--- a/src/reader/wgsl/parser_impl_function_decoration_list_test.cc
+++ b/src/reader/wgsl/parser_impl_function_decoration_list_test.cc
@@ -30,8 +30,8 @@ TEST_F(ParserImplTest, FunctionDecorationList_Parses) {
   EXPECT_TRUE(decos.matched);
   ASSERT_EQ(decos.value.size(), 2u);
 
-  auto* deco_0 = ast::As<ast::FunctionDecoration>(decos.value[0]);
-  auto* deco_1 = ast::As<ast::FunctionDecoration>(decos.value[1]);
+  auto* deco_0 = decos.value[0]->As<ast::FunctionDecoration>();
+  auto* deco_1 = decos.value[1]->As<ast::FunctionDecoration>();
   ASSERT_NE(deco_0, nullptr);
   ASSERT_NE(deco_1, nullptr);
 
diff --git a/src/reader/wgsl/parser_impl_function_decoration_test.cc b/src/reader/wgsl/parser_impl_function_decoration_test.cc
index 3877cbc1a2..966937bc97 100644
--- a/src/reader/wgsl/parser_impl_function_decoration_test.cc
+++ b/src/reader/wgsl/parser_impl_function_decoration_test.cc
@@ -30,7 +30,7 @@ TEST_F(ParserImplTest, FunctionDecoration_Workgroup) {
   EXPECT_FALSE(deco.errored);
   ASSERT_NE(deco.value, nullptr) << p->error();
   ASSERT_FALSE(p->has_error());
-  auto* func_deco = ast::As<ast::FunctionDecoration>(deco.value);
+  auto* func_deco = deco.value->As<ast::FunctionDecoration>();
   ASSERT_NE(func_deco, nullptr);
   ASSERT_TRUE(func_deco->IsWorkgroup());
 
@@ -50,7 +50,7 @@ TEST_F(ParserImplTest, FunctionDecoration_Workgroup_2Param) {
   EXPECT_FALSE(deco.errored);
   ASSERT_NE(deco.value, nullptr) << p->error();
   ASSERT_FALSE(p->has_error());
-  auto* func_deco = ast::As<ast::FunctionDecoration>(deco.value);
+  auto* func_deco = deco.value->As<ast::FunctionDecoration>();
   ASSERT_NE(func_deco, nullptr) << p->error();
   ASSERT_TRUE(func_deco->IsWorkgroup());
 
@@ -70,7 +70,7 @@ TEST_F(ParserImplTest, FunctionDecoration_Workgroup_3Param) {
   EXPECT_FALSE(deco.errored);
   ASSERT_NE(deco.value, nullptr) << p->error();
   ASSERT_FALSE(p->has_error());
-  auto* func_deco = ast::As<ast::FunctionDecoration>(deco.value);
+  auto* func_deco = deco.value->As<ast::FunctionDecoration>();
   ASSERT_NE(func_deco, nullptr);
   ASSERT_TRUE(func_deco->IsWorkgroup());
 
@@ -257,7 +257,7 @@ TEST_F(ParserImplTest, FunctionDecoration_Stage) {
   EXPECT_FALSE(deco.errored);
   ASSERT_NE(deco.value, nullptr) << p->error();
   ASSERT_FALSE(p->has_error());
-  auto* func_deco = ast::As<ast::FunctionDecoration>(deco.value);
+  auto* func_deco = deco.value->As<ast::FunctionDecoration>();
   ASSERT_NE(func_deco, nullptr);
   ASSERT_TRUE(func_deco->IsStage());
   EXPECT_EQ(func_deco->AsStage()->value(), ast::PipelineStage::kCompute);
diff --git a/src/reader/wgsl/parser_impl_struct_decoration_decl_test.cc b/src/reader/wgsl/parser_impl_struct_decoration_decl_test.cc
index a7f320d40f..3cfa9dc1e2 100644
--- a/src/reader/wgsl/parser_impl_struct_decoration_decl_test.cc
+++ b/src/reader/wgsl/parser_impl_struct_decoration_decl_test.cc
@@ -28,7 +28,7 @@ TEST_F(ParserImplTest, StructDecorationDecl_Parses) {
   EXPECT_FALSE(decos.errored);
   EXPECT_TRUE(decos.matched);
   ASSERT_EQ(decos.value.size(), 1u);
-  auto* struct_deco = ast::As<ast::StructDecoration>(decos.value[0]);
+  auto* struct_deco = decos.value[0]->As<ast::StructDecoration>();
   EXPECT_TRUE(struct_deco->IsBlock());
 }
 
diff --git a/src/reader/wgsl/parser_impl_struct_decoration_test.cc b/src/reader/wgsl/parser_impl_struct_decoration_test.cc
index 9e5f09a775..181045115c 100644
--- a/src/reader/wgsl/parser_impl_struct_decoration_test.cc
+++ b/src/reader/wgsl/parser_impl_struct_decoration_test.cc
@@ -43,7 +43,7 @@ TEST_P(StructDecorationTest, Parses) {
   EXPECT_TRUE(deco.matched);
   EXPECT_FALSE(deco.errored);
   ASSERT_NE(deco.value, nullptr);
-  auto* struct_deco = ast::As<ast::StructDecoration>(deco.value);
+  auto* struct_deco = deco.value->As<ast::StructDecoration>();
   ASSERT_NE(struct_deco, nullptr);
   EXPECT_EQ(struct_deco->IsBlock(), params.is_block);
 }
diff --git a/src/reader/wgsl/parser_impl_struct_member_decoration_decl_test.cc b/src/reader/wgsl/parser_impl_struct_member_decoration_decl_test.cc
index d158cec62c..6d0a3174e6 100644
--- a/src/reader/wgsl/parser_impl_struct_member_decoration_decl_test.cc
+++ b/src/reader/wgsl/parser_impl_struct_member_decoration_decl_test.cc
@@ -48,7 +48,7 @@ TEST_F(ParserImplTest, StructMemberDecorationDecl_Single) {
   EXPECT_FALSE(decos.errored);
   EXPECT_TRUE(decos.matched);
   ASSERT_EQ(decos.value.size(), 1u);
-  auto* deco = ast::As<ast::StructMemberDecoration>(decos.value[0]);
+  auto* deco = decos.value[0]->As<ast::StructMemberDecoration>();
   ASSERT_NE(deco, nullptr);
   EXPECT_TRUE(deco->IsOffset());
 }
diff --git a/src/reader/wgsl/parser_impl_struct_member_decoration_test.cc b/src/reader/wgsl/parser_impl_struct_member_decoration_test.cc
index 76da67abc5..c9f235784f 100644
--- a/src/reader/wgsl/parser_impl_struct_member_decoration_test.cc
+++ b/src/reader/wgsl/parser_impl_struct_member_decoration_test.cc
@@ -30,7 +30,7 @@ TEST_F(ParserImplTest, StructMemberDecoration_Offset) {
   ASSERT_NE(deco.value, nullptr);
   ASSERT_FALSE(p->has_error());
 
-  auto* member_deco = ast::As<ast::StructMemberDecoration>(deco.value);
+  auto* member_deco = deco.value->As<ast::StructMemberDecoration>();
   ASSERT_NE(member_deco, nullptr);
   ASSERT_TRUE(member_deco->IsOffset());
 
diff --git a/src/reader/wgsl/parser_impl_variable_decoration_list_test.cc b/src/reader/wgsl/parser_impl_variable_decoration_list_test.cc
index f10b13dded..81f5356cb6 100644
--- a/src/reader/wgsl/parser_impl_variable_decoration_list_test.cc
+++ b/src/reader/wgsl/parser_impl_variable_decoration_list_test.cc
@@ -31,8 +31,8 @@ TEST_F(ParserImplTest, VariableDecorationList_Parses) {
   ASSERT_TRUE(decos.matched);
   ASSERT_EQ(decos.value.size(), 2u);
 
-  auto* deco_0 = ast::As<ast::VariableDecoration>(decos.value[0]);
-  auto* deco_1 = ast::As<ast::VariableDecoration>(decos.value[1]);
+  auto* deco_0 = decos.value[0]->As<ast::VariableDecoration>();
+  auto* deco_1 = decos.value[1]->As<ast::VariableDecoration>();
   ASSERT_NE(deco_0, nullptr);
   ASSERT_NE(deco_1, nullptr);
 
diff --git a/src/reader/wgsl/parser_impl_variable_decoration_test.cc b/src/reader/wgsl/parser_impl_variable_decoration_test.cc
index ecef7b0ac6..3126df8b83 100644
--- a/src/reader/wgsl/parser_impl_variable_decoration_test.cc
+++ b/src/reader/wgsl/parser_impl_variable_decoration_test.cc
@@ -31,7 +31,7 @@ TEST_F(ParserImplTest, VariableDecoration_Location) {
   EXPECT_TRUE(deco.matched);
   EXPECT_FALSE(deco.errored);
   ASSERT_NE(deco.value, nullptr);
-  auto* var_deco = ast::As<ast::VariableDecoration>(deco.value);
+  auto* var_deco = deco.value->As<ast::VariableDecoration>();
   ASSERT_NE(var_deco, nullptr);
   ASSERT_FALSE(p->has_error());
   ASSERT_TRUE(var_deco->IsLocation());
@@ -101,7 +101,7 @@ TEST_P(BuiltinTest, VariableDecoration_Builtin) {
   EXPECT_TRUE(deco.matched);
   EXPECT_FALSE(deco.errored);
   ASSERT_NE(deco.value, nullptr);
-  auto* var_deco = ast::As<ast::VariableDecoration>(deco.value);
+  auto* var_deco = deco.value->As<ast::VariableDecoration>();
   ASSERT_FALSE(p->has_error()) << p->error();
   ASSERT_NE(var_deco, nullptr);
   ASSERT_TRUE(var_deco->IsBuiltin());
@@ -180,7 +180,7 @@ TEST_F(ParserImplTest, VariableDecoration_Binding) {
   EXPECT_TRUE(deco.matched);
   EXPECT_FALSE(deco.errored);
   ASSERT_NE(deco.value, nullptr);
-  auto* var_deco = ast::As<ast::VariableDecoration>(deco.value);
+  auto* var_deco = deco.value->As<ast::VariableDecoration>();
   ASSERT_NE(var_deco, nullptr);
   ASSERT_FALSE(p->has_error());
   ASSERT_TRUE(var_deco->IsBinding());
@@ -237,7 +237,7 @@ TEST_F(ParserImplTest, VariableDecoration_set) {
   EXPECT_TRUE(deco.matched);
   EXPECT_FALSE(deco.errored);
   ASSERT_NE(deco.value, nullptr);
-  auto* var_deco = ast::As<ast::VariableDecoration>(deco.value);
+  auto* var_deco = deco.value->As<ast::VariableDecoration>();
   ASSERT_FALSE(p->has_error());
   ASSERT_NE(var_deco, nullptr);
   ASSERT_TRUE(var_deco->IsSet());