From 3e727a6ea8d1d336ad8faaf9460994ee6e4658df Mon Sep 17 00:00:00 2001
From: Jay Herron <NeedleInAJayStack@protonmail.com>
Date: Thu, 18 Dec 2025 23:21:24 -0700
Subject: [PATCH 1/6] test: Adds benchmarks

---
 Benchmarks/Benchmarks/GraphQLBenchmarks.swift |  24 ++
 Benchmarks/Benchmarks/StarWarsData.swift      | 171 ++++++++++
 Benchmarks/Benchmarks/StarWarsSchema.swift    | 306 ++++++++++++++++++
 Benchmarks/Package.resolved                   |  86 +++++
 Benchmarks/Package.swift                      |  28 ++
 5 files changed, 615 insertions(+)
 create mode 100644 Benchmarks/Benchmarks/GraphQLBenchmarks.swift
 create mode 100644 Benchmarks/Benchmarks/StarWarsData.swift
 create mode 100644 Benchmarks/Benchmarks/StarWarsSchema.swift
 create mode 100644 Benchmarks/Package.resolved
 create mode 100644 Benchmarks/Package.swift

diff --git a/Benchmarks/Benchmarks/GraphQLBenchmarks.swift b/Benchmarks/Benchmarks/GraphQLBenchmarks.swift
new file mode 100644
index 00000000..d4ffc955
--- /dev/null
+++ b/Benchmarks/Benchmarks/GraphQLBenchmarks.swift
@@ -0,0 +1,24 @@
+import Benchmark
+import GraphQL
+
+let benchmarks: @Sendable () -> Void = {
+    Benchmark("graphql") { _ in
+        let result = try await graphql(
+            schema: starWarsSchema,
+            request: """
+            query NestedQuery {
+                hero {
+                    name
+                    friends {
+                        name
+                        appearsIn
+                        friends {
+                            name
+                        }
+                    }
+                }
+            }
+            """
+        )
+    }
+}
diff --git a/Benchmarks/Benchmarks/StarWarsData.swift b/Benchmarks/Benchmarks/StarWarsData.swift
new file mode 100644
index 00000000..c7959727
--- /dev/null
+++ b/Benchmarks/Benchmarks/StarWarsData.swift
@@ -0,0 +1,171 @@
+import GraphQL
+
+/**
+ * This defines a basic set of data for our Star Wars Schema.
+ *
+ * This data is hard coded for the sake of the demo, but you could imagine
+ * fetching this data from a backend service rather than from hardcoded
+ * values in a more complex demo.
+ */
+
+enum Episode: String, Encodable, Sendable {
+    case newHope = "NEWHOPE"
+    case empire = "EMPIRE"
+    case jedi = "JEDI"
+
+    init?(_ string: String?) {
+        guard let string = string else {
+            return nil
+        }
+
+        self.init(rawValue: string)
+    }
+}
+
+protocol Character: Encodable, Sendable {
+    var id: String { get }
+    var name: String { get }
+    var friends: [String] { get }
+    var appearsIn: [Episode] { get }
+}
+
+struct Human: Character {
+    let id: String
+    let name: String
+    let friends: [String]
+    let appearsIn: [Episode]
+    let homePlanet: String?
+
+    init(
+        id: String,
+        name: String,
+        friends: [String],
+        appearsIn: [Episode],
+        homePlanet: String? = nil
+    ) {
+        self.id = id
+        self.name = name
+        self.friends = friends
+        self.appearsIn = appearsIn
+        self.homePlanet = homePlanet
+    }
+}
+
+struct Droid: Character {
+    let id: String
+    let name: String
+    let friends: [String]
+    let appearsIn: [Episode]
+    let primaryFunction: String
+}
+
+let luke = Human(
+    id: "1000",
+    name: "Luke Skywalker",
+    friends: ["1002", "1003", "2000", "2001"],
+    appearsIn: [.newHope, .empire, .jedi],
+    homePlanet: "Tatooine"
+)
+
+let vader = Human(
+    id: "1001",
+    name: "Darth Vader",
+    friends: ["1004"],
+    appearsIn: [.newHope, .empire, .jedi],
+    homePlanet: "Tatooine"
+)
+
+let han = Human(
+    id: "1002",
+    name: "Han Solo",
+    friends: ["1000", "1003", "2001"],
+    appearsIn: [.newHope, .empire, .jedi]
+)
+
+let leia = Human(
+    id: "1003",
+    name: "Leia Organa",
+    friends: ["1000", "1002", "2000", "2001"],
+    appearsIn: [.newHope, .empire, .jedi],
+    homePlanet: "Alderaan"
+)
+
+let tarkin = Human(
+    id: "1004",
+    name: "Wilhuff Tarkin",
+    friends: ["1001"],
+    appearsIn: [.newHope]
+)
+
+let humanData: [String: Human] = [
+    "1000": luke,
+    "1001": vader,
+    "1002": han,
+    "1003": leia,
+    "1004": tarkin,
+]
+
+let c3po = Droid(
+    id: "2000",
+    name: "C-3PO",
+    friends: ["1000", "1002", "1003", "2001"],
+    appearsIn: [.newHope, .empire, .jedi],
+    primaryFunction: "Protocol"
+)
+
+let r2d2 = Droid(
+    id: "2001",
+    name: "R2-D2",
+    friends: ["1000", "1002", "1003"],
+    appearsIn: [.newHope, .empire, .jedi],
+    primaryFunction: "Astromech"
+)
+
+let droidData: [String: Droid] = [
+    "2000": c3po,
+    "2001": r2d2,
+]
+
+/**
+ * Helper function to get a character by ID.
+ */
+@Sendable func getCharacter(id: String) -> Character? {
+    return humanData[id] ?? droidData[id]
+}
+
+/**
+ * Allows us to query for a character"s friends.
+ */
+@Sendable func getFriends(character: Character) -> [Character] {
+    return character.friends.reduce(into: []) { friends, friendID in
+        if let friend = getCharacter(id: friendID) {
+            friends.append(friend)
+        }
+    }
+}
+
+/**
+ * Allows us to fetch the undisputed hero of the Star Wars trilogy, R2-D2.
+ */
+@Sendable func getHero(episode: Episode?) -> Character {
+    if episode == .empire {
+        // Luke is the hero of Episode V.
+        return luke
+    }
+    // R2-D2 is the hero otherwise.
+    return r2d2
+}
+
+/**
+ * Allows us to query for the human with the given id.
+ */
+@Sendable func getHuman(id: String) -> Human? {
+    return humanData[id]
+}
+
+/**
+ * Allows us to query for the droid with the given id.
+ */
+@Sendable func getDroid(id: String) -> Droid? {
+    return droidData[id]
+}
diff --git a/Benchmarks/Benchmarks/StarWarsSchema.swift b/Benchmarks/Benchmarks/StarWarsSchema.swift
new file mode 100644
index 00000000..23841438
--- /dev/null
+++ b/Benchmarks/Benchmarks/StarWarsSchema.swift
@@ -0,0 +1,306 @@
+import GraphQL
+
+/**
+ * This is designed to be an end-to-end test, demonstrating
+ * the full GraphQL stack.
+ *
+ * We will create a GraphQL schema that describes the major
+ * characters in the original Star Wars trilogy.
+ *
+ * NOTE: This may contain spoilers for the original Star
+ * Wars trilogy.
+ */
+
+/**
+ * Using our shorthand to describe type systems, the type system for our
+ * Star Wars example is:
+ *
+ * enum Episode { NEWHOPE, EMPIRE, JEDI }
+ *
+ * interface Character {
+ *   id: String!
+ *   name: String
+ *   friends: [Character]
+ *   appearsIn: [Episode]
+ * }
+ *
+ * type Human : Character {
+ *   id: String!
+ *   name: String
+ *   friends: [Character]
+ *   appearsIn: [Episode]
+ *   homePlanet: String
+ * }
+ *
+ * type Droid : Character {
+ *   id: String!
+ *   name: String
+ *   friends: [Character]
+ *   appearsIn: [Episode]
+ *   primaryFunction: String
+ * }
+ *
+ * type Query {
+ *   hero(episode: Episode): Character
+ *   human(id: String!): Human
+ *   droid(id: String!): Droid
+ * }
+ *
+ * We begin by setting up our schema.
+ */
+
+/**
+ * The original trilogy consists of three movies.
+ *
+ * This implements the following type system shorthand:
+ *   enum Episode { NEWHOPE, EMPIRE, JEDI }
+ */
+let EpisodeEnum = try! GraphQLEnumType(
+    name: "Episode",
+    description: "One of the films in the Star Wars Trilogy",
+    values: [
+        "NEWHOPE": GraphQLEnumValue(
+            value: Map(Episode.newHope.rawValue),
+            description: "Released in 1977."
+        ),
+        "EMPIRE": GraphQLEnumValue(
+            value: Map(Episode.empire.rawValue),
+            description: "Released in 1980."
+        ),
+        "JEDI": GraphQLEnumValue(
+            value: Map(Episode.jedi.rawValue),
+            description: "Released in 1983."
+        ),
+    ]
+)
+
+/**
+ * Characters in the Star Wars trilogy are either humans or droids.
+ *
+ * This implements the following type system shorthand:
+ *   interface Character {
+ *     id: String!
+ *     name: String
+ *     friends: [Character]
+ *     appearsIn: [Episode]
+ *     secretBackstory: String
+ *   }
+ */
+let CharacterInterface = try! GraphQLInterfaceType(
+    name: "Character",
+    description: "A character in the Star Wars Trilogy",
+    fields: { [
+        "id": GraphQLField(
+            type: GraphQLNonNull(GraphQLString),
+            description: "The id of the character."
+        ),
+        "name": GraphQLField(
+            type: GraphQLString,
+            description: "The name of the character."
+        ),
+        "friends": GraphQLField(
+            type: GraphQLList(CharacterInterface),
+            description: "The friends of the character, or an empty list if they have none."
+        ),
+        "appearsIn": GraphQLField(
+            type: GraphQLList(EpisodeEnum),
+            description: "Which movies they appear in."
+        ),
+        "secretBackstory": GraphQLField(
+            type: GraphQLString,
+            description: "All secrets about their past."
+        ),
+    ] },
+    resolveType: { character, _ in
+        switch character {
+        case is Human:
+            return "Human"
+        default:
+            return "Droid"
+        }
+    }
+)
+
+/**
+ * We define our human type, which implements the character interface.
+ *
+ * This implements the following type system shorthand:
+ *   type Human : Character {
+ *     id: String!
+ *     name: String
+ *     friends: [Character]
+ *     appearsIn: [Episode]
+ *     secretBackstory: String
+ *   }
+ */
+let HumanType = try! GraphQLObjectType(
+    name: "Human",
+    description: "A humanoid creature in the Star Wars universe.",
+    fields: [
+        "id": GraphQLField(
+            type: GraphQLNonNull(GraphQLString),
+            description: "The id of the human."
+        ),
+        "name": GraphQLField(
+            type: GraphQLString,
+            description: "The name of the human."
+        ),
+        "friends": GraphQLField(
+            type: GraphQLList(CharacterInterface),
+            description: "The friends of the human, or an empty list if they " +
+                "have none.",
+            resolve: { human, _, _, _ in
+                getFriends(character: human as! Human)
+            }
+        ),
+        "appearsIn": GraphQLField(
+            type: GraphQLList(EpisodeEnum),
+            description: "Which movies they appear in."
+        ),
+        "homePlanet": GraphQLField(
+            type: GraphQLString,
+            description: "The home planet of the human, or null if unknown."
+        ),
+        "secretBackstory": GraphQLField(
+            type: GraphQLString,
+            description: "Where are they from and how they came to be who they are.",
+            resolve: { _, _, _, _ in
+                struct Secret: Error, CustomStringConvertible {
+                    let description: String
+                }
+
+                throw Secret(description: "secretBackstory is secret.")
+            }
+        ),
+    ],
+    interfaces: [CharacterInterface],
+    isTypeOf: { source, _ in
+        source is Human
+    }
+)
+
+/**
+ * The other type of character in Star Wars is a droid.
+ *
+ * This implements the following type system shorthand:
+ *   type Droid : Character {
+ *     id: String!
+ *     name: String
+ *     friends: [Character]
+ *     appearsIn: [Episode]
+ *     secretBackstory: String
+ *     primaryFunction: String
+ *   }
+ */
+let DroidType = try! GraphQLObjectType(
+    name: "Droid",
+    description: "A mechanical creature in the Star Wars universe.",
+    fields: [
+        "id": GraphQLField(
+            type: GraphQLNonNull(GraphQLString),
+            description: "The id of the droid."
+        ),
+        "name": GraphQLField(
+            type: GraphQLString,
+            description: "The name of the droid."
+        ),
+        "friends": GraphQLField(
+            type: GraphQLList(CharacterInterface),
+            description: "The friends of the droid, or an empty list if they have none.",
+            resolve: { droid, _, _, _ in
+                getFriends(character: droid as! Droid)
+            }
+        ),
+        "appearsIn": GraphQLField(
+            type: GraphQLList(EpisodeEnum),
+            description: "Which movies they appear in."
+        ),
+        "secretBackstory": GraphQLField(
+            type: GraphQLString,
+            description: "Construction date and the name of the designer.",
+            resolve: { _, _, _, _ in
+                struct SecretError: Error, CustomStringConvertible {
+                    let description: String
+                }
+
+                throw SecretError(description: "secretBackstory is secret.")
+            }
+        ),
+        "primaryFunction": GraphQLField(
+            type: GraphQLString,
+            description: "The primary function of the droid."
+        ),
+    ],
+    interfaces: [CharacterInterface],
+    isTypeOf: { source, _ in
+        source is Droid
+    }
+)
+
+/**
+ * This is the type that will be the root of our query, and the
+ * entry point into our schema. It gives us the ability to fetch
+ * objects by their IDs, as well as to fetch the undisputed hero
+ * of the Star Wars trilogy, R2-D2, directly.
+ *
+ * This implements the following type system shorthand:
+ *   type Query {
+ *     hero(episode: Episode): Character
+ *     human(id: String!): Human
+ *     droid(id: String!): Droid
+ *   }
+ *
+ */
+let QueryType = try! GraphQLObjectType(
+    name: "Query",
+    fields: [
+        "hero": GraphQLField(
+            type: CharacterInterface,
+            args: [
+                "episode": GraphQLArgument(
+                    type: EpisodeEnum,
+                    description:
+                    "If omitted, returns the hero of the whole saga. If " +
+                        "provided, returns the hero of that particular episode."
+                ),
+            ],
+            resolve: { _, arguments, _, _ in
+                let episode = Episode(arguments["episode"].string)
+                return getHero(episode: episode)
+            }
+        ),
+        "human": GraphQLField(
+            type: HumanType,
+            args: [
+                "id": GraphQLArgument(
+                    type: GraphQLNonNull(GraphQLString),
+                    description: "id of the human"
+                ),
+            ],
+            resolve: { _, arguments, _, _ in
+                getHuman(id: arguments["id"].string!)
+            }
+        ),
+        "droid": GraphQLField(
+            type: DroidType,
+            args: [
+                "id": GraphQLArgument(
+                    type: GraphQLNonNull(GraphQLString),
+                    description: "id of the droid"
+                ),
+            ],
+            resolve: { _, arguments, _, _ in
+                getDroid(id: arguments["id"].string!)
+            }
+        ),
+    ]
+)
+
+/**
+ * Finally, we construct our schema (whose starting query type is the query
+ * type we defined above) and export it.
+ */
+let starWarsSchema = try! GraphQLSchema(
+    query: QueryType,
+    types: [HumanType, DroidType]
+)
diff --git a/Benchmarks/Package.resolved b/Benchmarks/Package.resolved
new file mode 100644
index 00000000..81906493
--- /dev/null
+++ b/Benchmarks/Package.resolved
@@ -0,0 +1,86 @@
+{
+  "pins" : [
+    {
+      "identity" : "hdrhistogram-swift",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/HdrHistogram/hdrhistogram-swift.git",
+      "state" : {
+        "revision" : "93a1618c8aa20f6a521a9da656a3e0591889e9dc",
+        "version" : "0.1.3"
+      }
+    },
+    {
+      "identity" : "package-benchmark",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/ordo-one/package-benchmark",
+      "state" : {
+        "revision" : "acfd97b98f5a40d963c89437e1cfaeab8ef10bf9",
+        "version" : "1.29.7"
+      }
+    },
+    {
+      "identity" : "package-jemalloc",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/ordo-one/package-jemalloc.git",
+      "state" : {
+        "revision" : "e8a5db026963f5bfeac842d9d3f2cc8cde323b49",
+        "version" : "1.0.0"
+      }
+    },
+    {
+      "identity" : "swift-argument-parser",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-argument-parser.git",
+      "state" : {
+        "revision" : "c5d11a805e765f52ba34ec7284bd4fcd6ba68615",
+        "version" : "1.7.0"
+      }
+    },
+    {
+      "identity" : "swift-atomics",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-atomics.git",
+      "state" : {
+        "revision" : "b601256eab081c0f92f059e12818ac1d4f178ff7",
+        "version" : "1.3.0"
+      }
+    },
+    {
+      "identity" : "swift-collections",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-collections",
+      "state" : {
+        "revision" : "7b847a3b7008b2dc2f47ca3110d8c782fb2e5c7e",
+        "version" : "1.3.0"
+      }
+    },
+    {
+      "identity" : "swift-numerics",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-numerics",
+      "state" : {
+        "revision" : "0c0290ff6b24942dadb83a929ffaaa1481df04a2",
+        "version" : "1.1.1"
+      }
+    },
+    {
+      "identity" : "swift-system",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-system.git",
+      "state" : {
+        "revision" : "395a77f0aa927f0ff73941d7ac35f2b46d47c9db",
+        "version" : "1.6.3"
+      }
+    },
+    {
+      "identity" : "texttable",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/ordo-one/TextTable.git",
+      "state" : {
+        "revision" : "a27a07300cf4ae322e0079ca0a475c5583dd575f",
+        "version" : "0.0.2"
+      }
+    }
+  ],
+  "version" : 2
+}
diff --git a/Benchmarks/Package.swift b/Benchmarks/Package.swift
new file mode 100644
index 00000000..b0b4e67a
--- /dev/null
+++ b/Benchmarks/Package.swift
@@ -0,0 +1,28 @@
+// swift-tools-version:5.8
+import PackageDescription
+
+let package = Package(
+    name: "Benchmarks",
+    platforms: [.macOS(.v13)],
+    dependencies: [
+        .package(name: "GraphQL", path: "../"),
+        .package(
+            url: "https://github.com/ordo-one/package-benchmark",
+            .upToNextMajor(from: "1.4.0")
+        ),
+    ],
+    targets: [
+        .executableTarget(
+            name: "Benchmarks",
+            dependencies: [
+                .product(name: "Benchmark", package: "package-benchmark"),
+                .product(name: "GraphQL", package: "GraphQL"),
+            ],
+            path: "Benchmarks",
+            plugins: [
+                .plugin(name: "BenchmarkPlugin", package: "package-benchmark"),
+            ]
+        ),
+    ],
+    swiftLanguageVersions: [.v5, .version("6")]
+)

From ea7564e9323ed55a382ae7432208b49ebf15cc09 Mon Sep 17 00:00:00 2001
From: Jay Herron <NeedleInAJayStack@protonmail.com>
Date: Sun, 21 Dec 2025 00:25:21 -0700
Subject: [PATCH 2/6] refactor(perf): Makes static regexes global

This reduces the benchmark `graphql` time by 51%, and malloc calls by 77%
---
 Sources/GraphQL/Error/SyntaxError.swift       | 17 +++++++-------
 Sources/GraphQL/Language/Location.swift       | 23 ++++++++-----------
 .../GraphQL/Utilities/AssertValidName.swift   |  9 +++++---
 3 files changed, 24 insertions(+), 25 deletions(-)

diff --git a/Sources/GraphQL/Error/SyntaxError.swift b/Sources/GraphQL/Error/SyntaxError.swift
index b16b9e34..18f2dbe9 100644
--- a/Sources/GraphQL/Error/SyntaxError.swift
+++ b/Sources/GraphQL/Error/SyntaxError.swift
@@ -53,15 +53,14 @@ func splitLines(string: String) -> [String] {
     var location = 0
 
     let nsstring = NSString(string: string)
-    do {
-        let regex = try NSRegularExpression(pattern: "\r\n|[\n\r]", options: [])
-        for match in regex.matches(in: string, options: [], range: NSRange(0 ..< nsstring.length)) {
-            let range = NSRange(location ..< match.range.location)
-            lines.append(nsstring.substring(with: range))
-            location = match.range.location + match.range.length
-        }
-    } catch {
-        // Let lines and location remain unchanged
+    for match in newLineRegex.matches(
+        in: string,
+        options: [],
+        range: NSRange(0 ..< nsstring.length)
+    ) {
+        let range = NSRange(location ..< match.range.location)
+        lines.append(nsstring.substring(with: range))
+        location = match.range.location + match.range.length
     }
 
     if lines.isEmpty {
diff --git a/Sources/GraphQL/Language/Location.swift b/Sources/GraphQL/Language/Location.swift
index 2c77f1c0..660d8b53 100644
--- a/Sources/GraphQL/Language/Location.swift
+++ b/Sources/GraphQL/Language/Location.swift
@@ -18,20 +18,17 @@ func getLocation(source: Source, position: Int) -> SourceLocation {
     var line = 1
     var column = position + 1
 
-    do {
-        let regex = try NSRegularExpression(pattern: "\r\n|[\n\r]", options: [])
-        let matches = regex.matches(
-            in: source.body,
-            options: [],
-            range: NSRange(0 ..< source.body.utf16.count)
-        )
-        for match in matches where match.range.location < position {
-            line += 1
-            column = position + 1 - (match.range.location + match.range.length)
-        }
-    } catch {
-        // Leave line and position unset if regex fails
+    let matches = newLineRegex.matches(
+        in: source.body,
+        options: [],
+        range: NSRange(0 ..< source.body.utf16.count)
+    )
+    for match in matches where match.range.location < position {
+        line += 1
+        column = position + 1 - (match.range.location + match.range.length)
     }
 
     return SourceLocation(line: line, column: column)
 }
+
+let newLineRegex = try! NSRegularExpression(pattern: "\r\n|[\n\r]", options: [])
diff --git a/Sources/GraphQL/Utilities/AssertValidName.swift b/Sources/GraphQL/Utilities/AssertValidName.swift
index 6bf3f6ee..5e95857d 100644
--- a/Sources/GraphQL/Utilities/AssertValidName.swift
+++ b/Sources/GraphQL/Utilities/AssertValidName.swift
@@ -12,9 +12,7 @@ public enum InvalidNameError: Error, CustomStringConvertible {
 }
 
 func assertValid(name: String) throws {
-    let regex = try NSRegularExpression(pattern: "^[_a-zA-Z][_a-zA-Z0-9]*$", options: [])
-
-    let range = regex.rangeOfFirstMatch(
+    let range = validNameRegex.rangeOfFirstMatch(
         in: name,
         options: [],
         range: NSRange(0 ..< name.utf16.count)
@@ -24,3 +22,8 @@ func assertValid(name: String) throws {
         throw InvalidNameError.invalidName(name)
     }
 }
+
+private let validNameRegex = try! NSRegularExpression(
+    pattern: "^[_a-zA-Z][_a-zA-Z0-9]*$",
+    options: []
+)

From f8e6ea02c535b1d4ee7254473ed1f254ca8c1ffd Mon Sep 17 00:00:00 2001
From: Jay Herron <NeedleInAJayStack@protonmail.com>
Date: Mon, 22 Dec 2025 01:26:00 -0700
Subject: [PATCH 3/6] refactor(perf): Reduces validation type casting

Reduces benchmark `graphql` request time by 5%, and `validateRequest` time by 13%
---
 .../Rules/Custom/NoDeprecatedCustomRule.swift | 23 +++++----
 .../NoSchemaIntrospectionCustomRule.swift     |  8 +++-
 .../Rules/ExecutableDefinitionsRule.swift     |  8 +++-
 .../Rules/FieldsOnCorrectTypeRule.swift       |  9 ++--
 .../Rules/FragmentsOnCompositeTypesRule.swift | 11 +++--
 .../KnownArgumentNamesOnDirectivesRule.swift  | 11 +++--
 .../Rules/KnownDirectivesRule.swift           |  3 +-
 .../Rules/KnownFragmentNamesRule.swift        |  9 ++--
 .../Validation/Rules/KnownTypeNamesRule.swift |  8 +++-
 .../Rules/LoneAnonymousOperationRule.swift    | 11 +++--
 .../Rules/LoneSchemaDefinitionRule.swift      |  8 +++-
 .../Rules/NoFragmentCyclesRule.swift          | 10 ++--
 .../Rules/NoUndefinedVariablesRule.swift      |  8 +++-
 .../Rules/NoUnusedFragmentsRule.swift         | 19 +++++---
 .../Rules/PossibleFragmentSpreadsRule.swift   | 15 +++---
 .../Rules/PossibleTypeExtensionsRule.swift    | 28 ++++++++---
 ...dedRequiredArgumentsOnDirectivesRule.swift |  8 +++-
 .../Rules/ProvidedRequiredArgumentsRule.swift | 14 ++++--
 .../Validation/Rules/ScalarLeafsRule.swift    |  9 ++--
 .../UniqueArgumentDefinitionNamesRule.swift   | 24 +++++++---
 .../Rules/UniqueArgumentNamesRule.swift       | 48 ++++++++++++-------
 .../Rules/UniqueDirectiveNamesRule.swift      |  8 +++-
 .../UniqueDirectivesPerLocationRule.swift     | 14 ++++--
 .../Rules/UniqueEnumValueNamesRule.swift      | 12 +++--
 .../UniqueFieldDefinitionNamesRule.swift      | 28 ++++++++---
 .../Rules/UniqueFragmentNamesRule.swift       |  8 +++-
 .../Rules/UniqueInputFieldNamesRule.swift     | 17 ++++---
 .../Rules/UniqueOperationNamesRule.swift      |  8 +++-
 .../Rules/UniqueOperationTypesRule.swift      | 12 +++--
 .../Rules/UniqueTypeNamesRule.swift           | 30 ++++++++----
 .../Rules/UniqueVariableNamesRule.swift       |  8 +++-
 .../Rules/ValuesOfCorrectTypeRule.swift       | 44 ++++++-----------
 .../Rules/VariablesAreInputTypesRule.swift    |  8 +++-
 .../Validation/ValidationContext.swift        | 25 +++++-----
 34 files changed, 340 insertions(+), 174 deletions(-)

diff --git a/Sources/GraphQL/Validation/Rules/Custom/NoDeprecatedCustomRule.swift b/Sources/GraphQL/Validation/Rules/Custom/NoDeprecatedCustomRule.swift
index 14836758..5dfc4f54 100644
--- a/Sources/GraphQL/Validation/Rules/Custom/NoDeprecatedCustomRule.swift
+++ b/Sources/GraphQL/Validation/Rules/Custom/NoDeprecatedCustomRule.swift
@@ -12,7 +12,9 @@
 public func NoDeprecatedCustomRule(context: ValidationContext) -> Visitor {
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let node = node as? Field {
+            switch node.kind {
+            case .field:
+                let node = node as! Field
                 if
                     let fieldDef = context.fieldDef,
                     let deprecationReason = fieldDef.deprecationReason,
@@ -25,8 +27,9 @@ public func NoDeprecatedCustomRule(context: ValidationContext) -> Visitor {
                         )
                     )
                 }
-            }
-            if let node = node as? Argument {
+                return .continue
+            case .argument:
+                let node = node as! Argument
                 if
                     let argDef = context.argument,
                     let deprecationReason = argDef.deprecationReason
@@ -50,8 +53,9 @@ public func NoDeprecatedCustomRule(context: ValidationContext) -> Visitor {
                         )
                     }
                 }
-            }
-            if let node = node as? ObjectField {
+                return .continue
+            case .objectField:
+                let node = node as! ObjectField
                 if
                     let inputObjectDef = context.parentInputType as? GraphQLInputObjectType,
                     let inputFieldDef = try? inputObjectDef.getFields()[node.name.value],
@@ -64,8 +68,9 @@ public func NoDeprecatedCustomRule(context: ValidationContext) -> Visitor {
                         )
                     )
                 }
-            }
-            if let node = node as? EnumValue {
+                return .continue
+            case .enumValue:
+                let node = node as! EnumValue
                 if
                     let enumValueDef = context.typeInfo.enumValue,
                     let deprecationReason = enumValueDef.deprecationReason,
@@ -78,8 +83,10 @@ public func NoDeprecatedCustomRule(context: ValidationContext) -> Visitor {
                         )
                     )
                 }
+                return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/Custom/NoSchemaIntrospectionCustomRule.swift b/Sources/GraphQL/Validation/Rules/Custom/NoSchemaIntrospectionCustomRule.swift
index c3cbd482..df72d617 100644
--- a/Sources/GraphQL/Validation/Rules/Custom/NoSchemaIntrospectionCustomRule.swift
+++ b/Sources/GraphQL/Validation/Rules/Custom/NoSchemaIntrospectionCustomRule.swift
@@ -12,7 +12,9 @@
 public func NoSchemaIntrospectionCustomRule(context: ValidationContext) -> Visitor {
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let node = node as? Field {
+            switch node.kind {
+            case .field:
+                let node = node as! Field
                 if
                     let type = getNamedType(type: context.type),
                     isIntrospectionType(type: type)
@@ -24,8 +26,10 @@ public func NoSchemaIntrospectionCustomRule(context: ValidationContext) -> Visit
                         )
                     )
                 }
+                return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/ExecutableDefinitionsRule.swift b/Sources/GraphQL/Validation/Rules/ExecutableDefinitionsRule.swift
index d62fa16f..2d4101f0 100644
--- a/Sources/GraphQL/Validation/Rules/ExecutableDefinitionsRule.swift
+++ b/Sources/GraphQL/Validation/Rules/ExecutableDefinitionsRule.swift
@@ -28,7 +28,9 @@ func ExecutableDefinitionsRule(context: ValidationContext) -> Visitor {
 
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let node = node as? Document {
+            switch node.kind {
+            case .document:
+                let node = node as! Document
                 for definition in node.definitions {
                     if !isExecutable(definition) {
                         var defName = "schema"
@@ -45,8 +47,10 @@ func ExecutableDefinitionsRule(context: ValidationContext) -> Visitor {
                         )
                     }
                 }
+                return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/FieldsOnCorrectTypeRule.swift b/Sources/GraphQL/Validation/Rules/FieldsOnCorrectTypeRule.swift
index 3994c0b4..8567bac6 100644
--- a/Sources/GraphQL/Validation/Rules/FieldsOnCorrectTypeRule.swift
+++ b/Sources/GraphQL/Validation/Rules/FieldsOnCorrectTypeRule.swift
@@ -24,7 +24,9 @@ func undefinedFieldMessage(
 func FieldsOnCorrectTypeRule(context: ValidationContext) -> Visitor {
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let node = node as? Field {
+            switch node.kind {
+            case .field:
+                let node = node as! Field
                 if let type = context.parentType {
                     let fieldDef = context.fieldDef
                     if fieldDef == nil {
@@ -59,9 +61,10 @@ func FieldsOnCorrectTypeRule(context: ValidationContext) -> Visitor {
                         ))
                     }
                 }
+                return .continue
+            default:
+                return .continue
             }
-
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/FragmentsOnCompositeTypesRule.swift b/Sources/GraphQL/Validation/Rules/FragmentsOnCompositeTypesRule.swift
index c8b6eeb0..359f9161 100644
--- a/Sources/GraphQL/Validation/Rules/FragmentsOnCompositeTypesRule.swift
+++ b/Sources/GraphQL/Validation/Rules/FragmentsOnCompositeTypesRule.swift
@@ -11,7 +11,9 @@
 func FragmentsOnCompositeTypesRule(context: ValidationContext) -> Visitor {
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let fragment = node as? InlineFragment {
+            switch node.kind {
+            case .inlineFragment:
+                let fragment = node as! InlineFragment
                 if let typeCondition = fragment.typeCondition {
                     if let type = typeFromAST(schema: context.schema, inputTypeAST: typeCondition) {
                         if type is GraphQLCompositeType {
@@ -28,8 +30,8 @@ func FragmentsOnCompositeTypesRule(context: ValidationContext) -> Visitor {
                     }
                 }
                 return .continue
-            }
-            if let fragment = node as? FragmentDefinition {
+            case .fragmentDefinition:
+                let fragment = node as! FragmentDefinition
                 let typeCondition = fragment.typeCondition
                 if let type = typeFromAST(schema: context.schema, inputTypeAST: typeCondition) {
                     if type is GraphQLCompositeType {
@@ -45,8 +47,9 @@ func FragmentsOnCompositeTypesRule(context: ValidationContext) -> Visitor {
                     )
                 }
                 return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/KnownArgumentNamesOnDirectivesRule.swift b/Sources/GraphQL/Validation/Rules/KnownArgumentNamesOnDirectivesRule.swift
index df62b18f..81ccb36f 100644
--- a/Sources/GraphQL/Validation/Rules/KnownArgumentNamesOnDirectivesRule.swift
+++ b/Sources/GraphQL/Validation/Rules/KnownArgumentNamesOnDirectivesRule.swift
@@ -11,7 +11,8 @@ func KnownArgumentNamesOnDirectivesRule(
 
     let astDefinitions = context.ast.definitions
     for def in astDefinitions {
-        if let def = def as? DirectiveDefinition {
+        if def.kind == .directiveDefinition {
+            let def = def as! DirectiveDefinition
             let argsNodes = def.arguments
             directiveArgs[def.name.value] = argsNodes.map(\.name.value)
         }
@@ -19,7 +20,9 @@ func KnownArgumentNamesOnDirectivesRule(
 
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let directiveNode = node as? Directive {
+            switch node.kind {
+            case .directive:
+                let directiveNode = node as! Directive
                 let directiveName = directiveNode.name.value
                 let knownArgs = directiveArgs[directiveName]
 
@@ -38,8 +41,10 @@ func KnownArgumentNamesOnDirectivesRule(
                         }
                     }
                 }
+                return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/KnownDirectivesRule.swift b/Sources/GraphQL/Validation/Rules/KnownDirectivesRule.swift
index 2e805254..8240fb1d 100644
--- a/Sources/GraphQL/Validation/Rules/KnownDirectivesRule.swift
+++ b/Sources/GraphQL/Validation/Rules/KnownDirectivesRule.swift
@@ -25,7 +25,8 @@ func KnownDirectivesRule(context: SDLorNormalValidationContext) -> Visitor {
 
     return Visitor(
         enter: { node, _, _, _, ancestors in
-            guard let node = node as? Directive else { return .continue }
+            guard node.kind == .directive else { return .continue }
+            let node = node as! Directive
 
             let name = node.name.value
 
diff --git a/Sources/GraphQL/Validation/Rules/KnownFragmentNamesRule.swift b/Sources/GraphQL/Validation/Rules/KnownFragmentNamesRule.swift
index a58591e4..6821b9f1 100644
--- a/Sources/GraphQL/Validation/Rules/KnownFragmentNamesRule.swift
+++ b/Sources/GraphQL/Validation/Rules/KnownFragmentNamesRule.swift
@@ -11,7 +11,9 @@ import Foundation
 func KnownFragmentNamesRule(context: ValidationContext) -> Visitor {
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let fragmentReference = node as? FragmentSpread {
+            switch node.kind {
+            case .fragmentSpread:
+                let fragmentReference = node as! FragmentSpread
                 let fragmentName = fragmentReference.name.value
                 let fragmentDefinition = context.getFragment(name: fragmentName)
 
@@ -21,9 +23,10 @@ func KnownFragmentNamesRule(context: ValidationContext) -> Visitor {
                         nodes: [fragmentReference.name]
                     ))
                 }
+                return .continue
+            default:
+                return .continue
             }
-
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/KnownTypeNamesRule.swift b/Sources/GraphQL/Validation/Rules/KnownTypeNamesRule.swift
index 6c47ea52..c8b276d8 100644
--- a/Sources/GraphQL/Validation/Rules/KnownTypeNamesRule.swift
+++ b/Sources/GraphQL/Validation/Rules/KnownTypeNamesRule.swift
@@ -28,7 +28,9 @@ func KnownTypeNamesRule(context: SDLorNormalValidationContext) -> Visitor {
 
     return Visitor(
         enter: { node, _, parent, _, ancestors in
-            if let type = node as? NamedType {
+            switch node.kind {
+            case .namedType:
+                let type = node as! NamedType
                 let typeName = type.name.value
                 if !typeNames.contains(typeName) {
                     let definitionNode = ancestors.count > 2 ? ancestors[2] : parent
@@ -52,8 +54,10 @@ func KnownTypeNamesRule(context: SDLorNormalValidationContext) -> Visitor {
                         )
                     )
                 }
+                return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/LoneAnonymousOperationRule.swift b/Sources/GraphQL/Validation/Rules/LoneAnonymousOperationRule.swift
index 783327ce..a2588a87 100644
--- a/Sources/GraphQL/Validation/Rules/LoneAnonymousOperationRule.swift
+++ b/Sources/GraphQL/Validation/Rules/LoneAnonymousOperationRule.swift
@@ -11,11 +11,13 @@ func LoneAnonymousOperationRule(context: ValidationContext) -> Visitor {
     var operationCount = 0
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let document = node as? Document {
+            switch node.kind {
+            case .document:
+                let document = node as! Document
                 operationCount = document.definitions.filter { $0 is OperationDefinition }.count
                 return .continue
-            }
-            if let operation = node as? OperationDefinition {
+            case .operationDefinition:
+                let operation = node as! OperationDefinition
                 if operation.name == nil, operationCount > 1 {
                     context.report(
                         error: GraphQLError(
@@ -25,8 +27,9 @@ func LoneAnonymousOperationRule(context: ValidationContext) -> Visitor {
                     )
                 }
                 return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/LoneSchemaDefinitionRule.swift b/Sources/GraphQL/Validation/Rules/LoneSchemaDefinitionRule.swift
index b1aa4428..f922ea0d 100644
--- a/Sources/GraphQL/Validation/Rules/LoneSchemaDefinitionRule.swift
+++ b/Sources/GraphQL/Validation/Rules/LoneSchemaDefinitionRule.swift
@@ -15,7 +15,9 @@ func LoneSchemaDefinitionRule(context: SDLValidationContext) -> Visitor {
     var schemaDefinitionsCount = 0
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let node = node as? SchemaDefinition {
+            switch node.kind {
+            case .schemaDefinition:
+                let node = node as! SchemaDefinition
                 if alreadyDefined {
                     context.report(
                         error: GraphQLError(
@@ -35,8 +37,10 @@ func LoneSchemaDefinitionRule(context: SDLValidationContext) -> Visitor {
                 }
 
                 schemaDefinitionsCount = schemaDefinitionsCount + 1
+                return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/NoFragmentCyclesRule.swift b/Sources/GraphQL/Validation/Rules/NoFragmentCyclesRule.swift
index acf56315..f2a47b3d 100644
--- a/Sources/GraphQL/Validation/Rules/NoFragmentCyclesRule.swift
+++ b/Sources/GraphQL/Validation/Rules/NoFragmentCyclesRule.swift
@@ -66,14 +66,16 @@ func NoFragmentCyclesRule(context: ValidationContext) -> Visitor {
 
     return Visitor(
         enter: { node, _, _, _, _ in
-            if node is OperationDefinition {
+            switch node.kind {
+            case .operationDefinition:
                 return .skip
-            }
-            if let fragmentDefinition = node as? FragmentDefinition {
+            case .fragmentDefinition:
+                let fragmentDefinition = node as! FragmentDefinition
                 detectCycleRecursive(fragment: fragmentDefinition)
                 return .skip
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/NoUndefinedVariablesRule.swift b/Sources/GraphQL/Validation/Rules/NoUndefinedVariablesRule.swift
index babe99ef..9e51193f 100644
--- a/Sources/GraphQL/Validation/Rules/NoUndefinedVariablesRule.swift
+++ b/Sources/GraphQL/Validation/Rules/NoUndefinedVariablesRule.swift
@@ -10,7 +10,9 @@
 func NoUndefinedVariablesRule(context: ValidationContext) -> Visitor {
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let operation = node as? OperationDefinition {
+            switch node.kind {
+            case .operationDefinition:
+                let operation = node as! OperationDefinition
                 let variableNameDefined = Set<String>(
                     operation.variableDefinitions.map { $0.variable.name.value }
                 )
@@ -35,8 +37,10 @@ func NoUndefinedVariablesRule(context: ValidationContext) -> Visitor {
                         )
                     }
                 }
+                return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/NoUnusedFragmentsRule.swift b/Sources/GraphQL/Validation/Rules/NoUnusedFragmentsRule.swift
index 05e2a868..7680396f 100644
--- a/Sources/GraphQL/Validation/Rules/NoUnusedFragmentsRule.swift
+++ b/Sources/GraphQL/Validation/Rules/NoUnusedFragmentsRule.swift
@@ -13,22 +13,25 @@ func NoUnusedFragmentsRule(context: ValidationContext) -> Visitor {
 
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let operation = node as? OperationDefinition {
+            switch node.kind {
+            case .operationDefinition:
+                let operation = node as! OperationDefinition
                 for fragment in context.getRecursivelyReferencedFragments(operation: operation) {
                     fragmentNameUsed.insert(fragment.name.value)
                 }
                 return .continue
-            }
-
-            if let fragment = node as? FragmentDefinition {
+            case .fragmentDefinition:
+                let fragment = node as! FragmentDefinition
                 fragmentDefs.append(fragment)
                 return .continue
+            default:
+                return .continue
             }
-            return .continue
         },
         leave: { node, _, _, _, _ -> VisitResult in
             // Use Document as proxy for the end of the visitation
-            if node is Document {
+            switch node.kind {
+            case .document:
                 for fragmentDef in fragmentDefs {
                     let fragName = fragmentDef.name.value
                     if !fragmentNameUsed.contains(fragName) {
@@ -40,8 +43,10 @@ func NoUnusedFragmentsRule(context: ValidationContext) -> Visitor {
                         )
                     }
                 }
+                return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/PossibleFragmentSpreadsRule.swift b/Sources/GraphQL/Validation/Rules/PossibleFragmentSpreadsRule.swift
index 015efd5b..4d3de756 100644
--- a/Sources/GraphQL/Validation/Rules/PossibleFragmentSpreadsRule.swift
+++ b/Sources/GraphQL/Validation/Rules/PossibleFragmentSpreadsRule.swift
@@ -8,7 +8,9 @@
 func PossibleFragmentSpreadsRule(context: ValidationContext) -> Visitor {
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let node = node as? InlineFragment {
+            switch node.kind {
+            case .inlineFragment:
+                let node = node as! InlineFragment
                 guard
                     let fragType = context.type as? GraphQLCompositeType,
                     let parentType = context.parentType
@@ -32,9 +34,9 @@ func PossibleFragmentSpreadsRule(context: ValidationContext) -> Visitor {
                         nodes: [node]
                     )
                 )
-            }
-
-            if let node = node as? FragmentSpread {
+                return .continue
+            case .fragmentSpread:
+                let node = node as! FragmentSpread
                 let fragName = node.name.value
 
                 guard
@@ -60,9 +62,10 @@ func PossibleFragmentSpreadsRule(context: ValidationContext) -> Visitor {
                         nodes: [node]
                     )
                 )
+                return .continue
+            default:
+                return .continue
             }
-
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/PossibleTypeExtensionsRule.swift b/Sources/GraphQL/Validation/Rules/PossibleTypeExtensionsRule.swift
index 9e5d3a53..055e4373 100644
--- a/Sources/GraphQL/Validation/Rules/PossibleTypeExtensionsRule.swift
+++ b/Sources/GraphQL/Validation/Rules/PossibleTypeExtensionsRule.swift
@@ -18,20 +18,34 @@ func PossibleTypeExtensionsRule(
 
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let node = node as? ScalarExtensionDefinition {
+            switch node.kind {
+            case .scalarExtensionDefinition:
+                let node = node as! ScalarExtensionDefinition
                 checkExtension(node: node)
-            } else if let node = node as? TypeExtensionDefinition {
+                return .continue
+            case .typeExtensionDefinition:
+                let node = node as! TypeExtensionDefinition
                 checkExtension(node: node)
-            } else if let node = node as? InterfaceExtensionDefinition {
+                return .continue
+            case .interfaceExtensionDefinition:
+                let node = node as! InterfaceExtensionDefinition
                 checkExtension(node: node)
-            } else if let node = node as? UnionExtensionDefinition {
+                return .continue
+            case .unionExtensionDefinition:
+                let node = node as! UnionExtensionDefinition
                 checkExtension(node: node)
-            } else if let node = node as? EnumExtensionDefinition {
+                return .continue
+            case .enumExtensionDefinition:
+                let node = node as! EnumExtensionDefinition
                 checkExtension(node: node)
-            } else if let node = node as? InputObjectExtensionDefinition {
+                return .continue
+            case .inputObjectExtensionDefinition:
+                let node = node as! InputObjectExtensionDefinition
                 checkExtension(node: node)
+                return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 
diff --git a/Sources/GraphQL/Validation/Rules/ProvidedRequiredArgumentsOnDirectivesRule.swift b/Sources/GraphQL/Validation/Rules/ProvidedRequiredArgumentsOnDirectivesRule.swift
index f4211e15..b9319a91 100644
--- a/Sources/GraphQL/Validation/Rules/ProvidedRequiredArgumentsOnDirectivesRule.swift
+++ b/Sources/GraphQL/Validation/Rules/ProvidedRequiredArgumentsOnDirectivesRule.swift
@@ -29,7 +29,9 @@ func ProvidedRequiredArgumentsOnDirectivesRule(
     return Visitor(
         // Validate on leave to allow for deeper errors to appear first.
         leave: { node, _, _, _, _ in
-            if let directiveNode = node as? Directive {
+            switch node.kind {
+            case .directive:
+                let directiveNode = node as! Directive
                 let directiveName = directiveNode.name.value
                 if let requiredArgs = requiredArgsMap[directiveName] {
                     let argNodes = directiveNode.arguments
@@ -45,8 +47,10 @@ func ProvidedRequiredArgumentsOnDirectivesRule(
                         }
                     }
                 }
+                return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/ProvidedRequiredArgumentsRule.swift b/Sources/GraphQL/Validation/Rules/ProvidedRequiredArgumentsRule.swift
index 85953b59..296b867e 100644
--- a/Sources/GraphQL/Validation/Rules/ProvidedRequiredArgumentsRule.swift
+++ b/Sources/GraphQL/Validation/Rules/ProvidedRequiredArgumentsRule.swift
@@ -37,7 +37,9 @@ func ProvidedRequiredArgumentsRule(context: ValidationContext) -> Visitor {
 
     return Visitor(
         leave: { node, _, _, _, _ in
-            if let fieldNode = node as? Field {
+            switch node.kind {
+            case .field:
+                let fieldNode = node as! Field
                 guard let fieldDef = context.fieldDef else {
                     return .continue
                 }
@@ -52,9 +54,9 @@ func ProvidedRequiredArgumentsRule(context: ValidationContext) -> Visitor {
                         ))
                     }
                 }
-            }
-
-            if let directiveNode = node as? Directive {
+                return .continue
+            case .directive:
+                let directiveNode = node as! Directive
                 let directiveName = directiveNode.name.value
 
                 if let requiredArgs = requiredArgsMap[directiveName] {
@@ -69,8 +71,10 @@ func ProvidedRequiredArgumentsRule(context: ValidationContext) -> Visitor {
                         }
                     }
                 }
+                return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/ScalarLeafsRule.swift b/Sources/GraphQL/Validation/Rules/ScalarLeafsRule.swift
index 201b40fb..b381c4ef 100644
--- a/Sources/GraphQL/Validation/Rules/ScalarLeafsRule.swift
+++ b/Sources/GraphQL/Validation/Rules/ScalarLeafsRule.swift
@@ -17,7 +17,9 @@ func requiredSubselectionMessage(fieldName: String, type: GraphQLType) -> String
 func ScalarLeafsRule(context: ValidationContext) -> Visitor {
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let node = node as? Field {
+            switch node.kind {
+            case .field:
+                let node = node as! Field
                 if let type = context.type {
                     if isLeafType(type: getNamedType(type: type)) {
                         if let selectionSet = node.selectionSet {
@@ -41,9 +43,10 @@ func ScalarLeafsRule(context: ValidationContext) -> Visitor {
                         context.report(error: error)
                     }
                 }
+                return .continue
+            default:
+                return .continue
             }
-
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/UniqueArgumentDefinitionNamesRule.swift b/Sources/GraphQL/Validation/Rules/UniqueArgumentDefinitionNamesRule.swift
index 76ea7e2b..1f97dfaa 100644
--- a/Sources/GraphQL/Validation/Rules/UniqueArgumentDefinitionNamesRule.swift
+++ b/Sources/GraphQL/Validation/Rules/UniqueArgumentDefinitionNamesRule.swift
@@ -10,28 +10,40 @@ func UniqueArgumentDefinitionNamesRule(
 ) -> Visitor {
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let directiveNode = node as? DirectiveDefinition {
+            switch node.kind {
+            case .directiveDefinition:
+                let directiveNode = node as! DirectiveDefinition
                 let argumentNodes = directiveNode.arguments
                 checkArgUniqueness(
                     parentName: "@\(directiveNode.name.value)",
                     argumentNodes: argumentNodes
                 )
-            } else if let node = node as? InterfaceTypeDefinition {
+                return .continue
+            case .interfaceTypeDefinition:
+                let node = node as! InterfaceTypeDefinition
                 checkArgUniquenessPerField(name: node.name, fields: node.fields)
-            } else if let node = node as? InterfaceExtensionDefinition {
+                return .continue
+            case .interfaceExtensionDefinition:
+                let node = node as! InterfaceExtensionDefinition
                 checkArgUniquenessPerField(
                     name: node.definition.name,
                     fields: node.definition.fields
                 )
-            } else if let node = node as? ObjectTypeDefinition {
+                return .continue
+            case .objectTypeDefinition:
+                let node = node as! ObjectTypeDefinition
                 checkArgUniquenessPerField(name: node.name, fields: node.fields)
-            } else if let node = node as? TypeExtensionDefinition {
+                return .continue
+            case .typeExtensionDefinition:
+                let node = node as! TypeExtensionDefinition
                 checkArgUniquenessPerField(
                     name: node.definition.name,
                     fields: node.definition.fields
                 )
+                return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 
diff --git a/Sources/GraphQL/Validation/Rules/UniqueArgumentNamesRule.swift b/Sources/GraphQL/Validation/Rules/UniqueArgumentNamesRule.swift
index 20445a3f..3417560c 100644
--- a/Sources/GraphQL/Validation/Rules/UniqueArgumentNamesRule.swift
+++ b/Sources/GraphQL/Validation/Rules/UniqueArgumentNamesRule.swift
@@ -10,28 +10,42 @@
 func UniqueArgumentNamesRule(context: ASTValidationContext) -> Visitor {
     return Visitor(
         enter: { node, _, _, _, _ in
-            let argumentNodes: [Argument]
-            if let field = node as? Field {
-                argumentNodes = field.arguments
-            } else if let directive = node as? Directive {
-                argumentNodes = directive.arguments
-            } else {
-                return .continue
-            }
+            switch node.kind {
+            case .field:
+                let field = node as! Field
+                let argumentNodes = field.arguments
+                let seenArgs = Dictionary(grouping: argumentNodes) { $0.name.value }
 
-            let seenArgs = Dictionary(grouping: argumentNodes) { $0.name.value }
+                for (argName, argNodes) in seenArgs {
+                    if argNodes.count > 1 {
+                        context.report(
+                            error: GraphQLError(
+                                message: "There can be only one argument named \"\(argName)\".",
+                                nodes: argNodes.map { $0.name }
+                            )
+                        )
+                    }
+                }
+                return .continue
+            case .directive:
+                let directive = node as! Directive
+                let argumentNodes = directive.arguments
+                let seenArgs = Dictionary(grouping: argumentNodes) { $0.name.value }
 
-            for (argName, argNodes) in seenArgs {
-                if argNodes.count > 1 {
-                    context.report(
-                        error: GraphQLError(
-                            message: "There can be only one argument named \"\(argName)\".",
-                            nodes: argNodes.map { $0.name }
+                for (argName, argNodes) in seenArgs {
+                    if argNodes.count > 1 {
+                        context.report(
+                            error: GraphQLError(
+                                message: "There can be only one argument named \"\(argName)\".",
+                                nodes: argNodes.map { $0.name }
+                            )
                         )
-                    )
+                    }
                 }
+                return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/UniqueDirectiveNamesRule.swift b/Sources/GraphQL/Validation/Rules/UniqueDirectiveNamesRule.swift
index 083f92aa..5b44ee0b 100644
--- a/Sources/GraphQL/Validation/Rules/UniqueDirectiveNamesRule.swift
+++ b/Sources/GraphQL/Validation/Rules/UniqueDirectiveNamesRule.swift
@@ -12,7 +12,9 @@ func UniqueDirectiveNamesRule(
 
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let node = node as? DirectiveDefinition {
+            switch node.kind {
+            case .directiveDefinition:
+                let node = node as! DirectiveDefinition
                 let directiveName = node.name.value
                 if schema?.getDirective(name: directiveName) != nil {
                     context.report(
@@ -33,8 +35,10 @@ func UniqueDirectiveNamesRule(
                 } else {
                     knownDirectiveNames[directiveName] = node.name
                 }
+                return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/UniqueDirectivesPerLocationRule.swift b/Sources/GraphQL/Validation/Rules/UniqueDirectivesPerLocationRule.swift
index d5393973..8e2296f3 100644
--- a/Sources/GraphQL/Validation/Rules/UniqueDirectivesPerLocationRule.swift
+++ b/Sources/GraphQL/Validation/Rules/UniqueDirectivesPerLocationRule.swift
@@ -38,16 +38,24 @@ func UniqueDirectivesPerLocationRule(context: SDLorNormalValidationContext) -> V
                 let directives = directiveNodes as? [Directive]
             {
                 var seenDirectives = [String: Directive]()
-                if node.kind == .schemaDefinition || node.kind == .schemaExtensionDefinition {
+                switch node.kind {
+                case .schemaDefinition, .schemaExtensionDefinition:
                     seenDirectives = schemaDirectives
-                } else if let node = node as? TypeDefinition {
+                case .enumTypeDefinition, .unionTypeDefinition, .objectTypeDefinition,
+                     .scalarTypeDefinition, .interfaceTypeDefinition, .operationTypeDefinition,
+                     .inputObjectTypeDefinition:
+                    let node = node as! TypeDefinition
                     let typeName = node.name.value
                     seenDirectives = typeDirectivesMap[typeName] ?? [:]
                     typeDirectivesMap[typeName] = seenDirectives
-                } else if let node = node as? TypeExtensionDefinition {
+                case .typeExtensionDefinition:
+                    let node = node as! TypeExtensionDefinition
                     let typeName = node.definition.name.value
                     seenDirectives = typeDirectivesMap[typeName] ?? [:]
                     typeDirectivesMap[typeName] = seenDirectives
+                default:
+                    // Do nothing
+                    break
                 }
 
                 for directive in directives {
diff --git a/Sources/GraphQL/Validation/Rules/UniqueEnumValueNamesRule.swift b/Sources/GraphQL/Validation/Rules/UniqueEnumValueNamesRule.swift
index 9f162849..2bf50b85 100644
--- a/Sources/GraphQL/Validation/Rules/UniqueEnumValueNamesRule.swift
+++ b/Sources/GraphQL/Validation/Rules/UniqueEnumValueNamesRule.swift
@@ -13,12 +13,18 @@ func UniqueEnumValueNamesRule(
 
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let definition = node as? EnumTypeDefinition {
+            switch node.kind {
+            case .enumTypeDefinition:
+                let definition = node as! EnumTypeDefinition
                 checkValueUniqueness(node: definition)
-            } else if let definition = node as? EnumExtensionDefinition {
+                return .continue
+            case .enumExtensionDefinition:
+                let definition = node as! EnumExtensionDefinition
                 checkValueUniqueness(node: definition.definition)
+                return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 
diff --git a/Sources/GraphQL/Validation/Rules/UniqueFieldDefinitionNamesRule.swift b/Sources/GraphQL/Validation/Rules/UniqueFieldDefinitionNamesRule.swift
index ff8f8333..bd39fe04 100644
--- a/Sources/GraphQL/Validation/Rules/UniqueFieldDefinitionNamesRule.swift
+++ b/Sources/GraphQL/Validation/Rules/UniqueFieldDefinitionNamesRule.swift
@@ -13,20 +13,34 @@ func UniqueFieldDefinitionNamesRule(
 
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let node = node as? InputObjectTypeDefinition {
+            switch node.kind {
+            case .inputObjectTypeDefinition:
+                let node = node as! InputObjectTypeDefinition
                 checkFieldUniqueness(name: node.name, fields: node.fields)
-            } else if let node = node as? InputObjectExtensionDefinition {
+                return .continue
+            case .inputObjectExtensionDefinition:
+                let node = node as! InputObjectExtensionDefinition
                 checkFieldUniqueness(name: node.name, fields: node.definition.fields)
-            } else if let node = node as? InterfaceTypeDefinition {
+                return .continue
+            case .interfaceTypeDefinition:
+                let node = node as! InterfaceTypeDefinition
                 checkFieldUniqueness(name: node.name, fields: node.fields)
-            } else if let node = node as? InterfaceExtensionDefinition {
+                return .continue
+            case .interfaceExtensionDefinition:
+                let node = node as! InterfaceExtensionDefinition
                 checkFieldUniqueness(name: node.name, fields: node.definition.fields)
-            } else if let node = node as? ObjectTypeDefinition {
+                return .continue
+            case .objectTypeDefinition:
+                let node = node as! ObjectTypeDefinition
                 checkFieldUniqueness(name: node.name, fields: node.fields)
-            } else if let node = node as? TypeExtensionDefinition {
+                return .continue
+            case .typeExtensionDefinition:
+                let node = node as! TypeExtensionDefinition
                 checkFieldUniqueness(name: node.name, fields: node.definition.fields)
+                return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 
diff --git a/Sources/GraphQL/Validation/Rules/UniqueFragmentNamesRule.swift b/Sources/GraphQL/Validation/Rules/UniqueFragmentNamesRule.swift
index 905b09a0..ef6810ec 100644
--- a/Sources/GraphQL/Validation/Rules/UniqueFragmentNamesRule.swift
+++ b/Sources/GraphQL/Validation/Rules/UniqueFragmentNamesRule.swift
@@ -10,7 +10,9 @@ func UniqueFragmentNamesRule(context: ValidationContext) -> Visitor {
     var knownFragmentNames = [String: Name]()
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let fragment = node as? FragmentDefinition {
+            switch node.kind {
+            case .fragmentDefinition:
+                let fragment = node as! FragmentDefinition
                 let fragmentName = fragment.name
                 if let knownFragmentName = knownFragmentNames[fragmentName.value] {
                     context.report(
@@ -22,8 +24,10 @@ func UniqueFragmentNamesRule(context: ValidationContext) -> Visitor {
                 } else {
                     knownFragmentNames[fragmentName.value] = fragmentName
                 }
+                return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/UniqueInputFieldNamesRule.swift b/Sources/GraphQL/Validation/Rules/UniqueInputFieldNamesRule.swift
index 374eea72..076a8915 100644
--- a/Sources/GraphQL/Validation/Rules/UniqueInputFieldNamesRule.swift
+++ b/Sources/GraphQL/Validation/Rules/UniqueInputFieldNamesRule.swift
@@ -13,12 +13,13 @@ func UniqueInputFieldNamesRule(context: ASTValidationContext) -> Visitor {
 
     return Visitor(
         enter: { node, _, _, _, _ in
-            if node is ObjectValue {
+            switch node.kind {
+            case .objectValue:
                 knownNameStack.append(knownNames)
                 knownNames = [:]
                 return .continue
-            }
-            if let objectField = node as? ObjectField {
+            case .objectField:
+                let objectField = node as! ObjectField
                 let fieldName = objectField.name.value
                 if let knownName = knownNames[fieldName] {
                     context.report(
@@ -31,15 +32,19 @@ func UniqueInputFieldNamesRule(context: ASTValidationContext) -> Visitor {
                     knownNames[fieldName] = objectField.name
                 }
                 return .continue
+            default:
+                return .continue
             }
-            return .continue
         },
         leave: { node, _, _, _, _ in
-            if node is ObjectValue {
+            switch node.kind {
+            case .objectValue:
                 let prevKnownNames = knownNameStack.popLast()
                 knownNames = prevKnownNames ?? [:]
+                return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/UniqueOperationNamesRule.swift b/Sources/GraphQL/Validation/Rules/UniqueOperationNamesRule.swift
index 60b91438..2ff7f786 100644
--- a/Sources/GraphQL/Validation/Rules/UniqueOperationNamesRule.swift
+++ b/Sources/GraphQL/Validation/Rules/UniqueOperationNamesRule.swift
@@ -10,7 +10,9 @@ func UniqueOperationNamesRule(context: ValidationContext) -> Visitor {
     var knownOperationNames = [String: Name]()
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let operation = node as? OperationDefinition {
+            switch node.kind {
+            case .operationDefinition:
+                let operation = node as! OperationDefinition
                 if let operationName = operation.name {
                     if let knownOperationName = knownOperationNames[operationName.value] {
                         context.report(
@@ -23,8 +25,10 @@ func UniqueOperationNamesRule(context: ValidationContext) -> Visitor {
                         knownOperationNames[operationName.value] = operationName
                     }
                 }
+                return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/UniqueOperationTypesRule.swift b/Sources/GraphQL/Validation/Rules/UniqueOperationTypesRule.swift
index 95e52787..c438cae5 100644
--- a/Sources/GraphQL/Validation/Rules/UniqueOperationTypesRule.swift
+++ b/Sources/GraphQL/Validation/Rules/UniqueOperationTypesRule.swift
@@ -25,12 +25,18 @@ func UniqueOperationTypesRule(
 
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let operation = node as? SchemaDefinition {
+            switch node.kind {
+            case .schemaDefinition:
+                let operation = node as! SchemaDefinition
                 checkOperationTypes(operation.operationTypes)
-            } else if let operation = node as? SchemaExtensionDefinition {
+                return .continue
+            case .schemaExtensionDefinition:
+                let operation = node as! SchemaExtensionDefinition
                 checkOperationTypes(operation.definition.operationTypes)
+                return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 
diff --git a/Sources/GraphQL/Validation/Rules/UniqueTypeNamesRule.swift b/Sources/GraphQL/Validation/Rules/UniqueTypeNamesRule.swift
index de20290b..427deeee 100644
--- a/Sources/GraphQL/Validation/Rules/UniqueTypeNamesRule.swift
+++ b/Sources/GraphQL/Validation/Rules/UniqueTypeNamesRule.swift
@@ -10,22 +10,34 @@ func UniqueTypeNamesRule(context: SDLValidationContext) -> Visitor {
 
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let definition = node as? ScalarTypeDefinition {
+            switch node.kind {
+            case .scalarTypeDefinition:
+                let definition = node as! ScalarTypeDefinition
                 checkTypeName(node: definition)
-            } else if let definition = node as? ObjectTypeDefinition {
+                return .continue
+            case .objectTypeDefinition:
+                let definition = node as! ObjectTypeDefinition
                 checkTypeName(node: definition)
-            } else if let definition = node as? InterfaceTypeDefinition {
+                return .continue
+            case .interfaceTypeDefinition:
+                let definition = node as! InterfaceTypeDefinition
                 checkTypeName(node: definition)
-            } else if let definition = node as? InterfaceTypeDefinition {
+                return .continue
+            case .unionTypeDefinition:
+                let definition = node as! UnionTypeDefinition
                 checkTypeName(node: definition)
-            } else if let definition = node as? UnionTypeDefinition {
+                return .continue
+            case .enumTypeDefinition:
+                let definition = node as! EnumTypeDefinition
                 checkTypeName(node: definition)
-            } else if let definition = node as? EnumTypeDefinition {
-                checkTypeName(node: definition)
-            } else if let definition = node as? InputObjectTypeDefinition {
+                return .continue
+            case .inputObjectTypeDefinition:
+                let definition = node as! InputObjectTypeDefinition
                 checkTypeName(node: definition)
+                return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 
diff --git a/Sources/GraphQL/Validation/Rules/UniqueVariableNamesRule.swift b/Sources/GraphQL/Validation/Rules/UniqueVariableNamesRule.swift
index 1339304e..5c2d5782 100644
--- a/Sources/GraphQL/Validation/Rules/UniqueVariableNamesRule.swift
+++ b/Sources/GraphQL/Validation/Rules/UniqueVariableNamesRule.swift
@@ -7,7 +7,9 @@
 func UniqueVariableNamesRule(context: ValidationContext) -> Visitor {
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let operation = node as? OperationDefinition {
+            switch node.kind {
+            case .operationDefinition:
+                let operation = node as! OperationDefinition
                 let variableDefinitions = operation.variableDefinitions
 
                 let seenVariableDefinitions = Dictionary(grouping: variableDefinitions) { node in
@@ -24,8 +26,10 @@ func UniqueVariableNamesRule(context: ValidationContext) -> Visitor {
                         )
                     }
                 }
+                return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/ValuesOfCorrectTypeRule.swift b/Sources/GraphQL/Validation/Rules/ValuesOfCorrectTypeRule.swift
index 4ce84608..494169d9 100644
--- a/Sources/GraphQL/Validation/Rules/ValuesOfCorrectTypeRule.swift
+++ b/Sources/GraphQL/Validation/Rules/ValuesOfCorrectTypeRule.swift
@@ -12,15 +12,16 @@ func ValuesOfCorrectTypeRule(context: ValidationContext) -> Visitor {
 
     return Visitor(
         enter: { node, _, _, _, _ in
-            if node is OperationDefinition {
+            switch node.kind {
+            case .operationDefinition:
                 variableDefinitions = [:]
                 return .continue
-            }
-            if let variableDefinition = node as? VariableDefinition {
+            case .variableDefinition:
+                let variableDefinition = node as! VariableDefinition
                 variableDefinitions[variableDefinition.variable.name.value] = variableDefinition
                 return .continue
-            }
-            if let list = node as? ListValue {
+            case .listValue:
+                let list = node as! ListValue
                 guard let type = getNullableType(type: context.parentInputType) else {
                     return .continue
                 }
@@ -29,8 +30,8 @@ func ValuesOfCorrectTypeRule(context: ValidationContext) -> Visitor {
                     return .break // Don't traverse further.
                 }
                 return .continue
-            }
-            if let object = node as? ObjectValue {
+            case .objectValue:
+                let object = node as! ObjectValue
                 let type = getNamedType(type: context.inputType)
                 guard let type = type as? GraphQLInputObjectType else {
                     isValidValueNode(context, object)
@@ -64,8 +65,8 @@ func ValuesOfCorrectTypeRule(context: ValidationContext) -> Visitor {
                     )
                 }
                 return .continue
-            }
-            if let field = node as? ObjectField {
+            case .objectField:
+                let field = node as! ObjectField
                 let parentType = getNamedType(type: context.parentInputType)
                 if
                     context.inputType == nil,
@@ -86,8 +87,8 @@ func ValuesOfCorrectTypeRule(context: ValidationContext) -> Visitor {
                     )
                 }
                 return .continue
-            }
-            if let null = node as? NullValue {
+            case .nullValue:
+                let null = node as! NullValue
                 let type = context.inputType
                 if let type = type as? GraphQLNonNull {
                     context.report(
@@ -99,28 +100,13 @@ func ValuesOfCorrectTypeRule(context: ValidationContext) -> Visitor {
                     )
                 }
                 return .continue
-            }
-            if let node = node as? EnumValue {
-                isValidValueNode(context, node)
-                return .continue
-            }
-            if let node = node as? IntValue {
+            case .enumValue, .intValue, .floatValue, .stringValue, .booleanValue:
+                let node = node as! Value
                 isValidValueNode(context, node)
                 return .continue
-            }
-            if let node = node as? FloatValue {
-                isValidValueNode(context, node)
-                return .continue
-            }
-            if let node = node as? StringValue {
-                isValidValueNode(context, node)
-                return .continue
-            }
-            if let node = node as? BooleanValue {
-                isValidValueNode(context, node)
+            default:
                 return .continue
             }
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/Rules/VariablesAreInputTypesRule.swift b/Sources/GraphQL/Validation/Rules/VariablesAreInputTypesRule.swift
index 847d576a..60f5ef7c 100644
--- a/Sources/GraphQL/Validation/Rules/VariablesAreInputTypesRule.swift
+++ b/Sources/GraphQL/Validation/Rules/VariablesAreInputTypesRule.swift
@@ -10,7 +10,9 @@
 func VariablesAreInputTypesRule(context: ValidationContext) -> Visitor {
     return Visitor(
         enter: { node, _, _, _, _ in
-            if let variableDefinition = node as? VariableDefinition {
+            switch node.kind {
+            case .variableDefinition:
+                let variableDefinition = node as! VariableDefinition
                 let variableType = variableDefinition.type
                 if let type = typeFromAST(schema: context.schema, inputTypeAST: variableType) {
                     guard !isInputType(type: type) else {
@@ -26,8 +28,10 @@ func VariablesAreInputTypesRule(context: ValidationContext) -> Visitor {
                         )
                     )
                 }
+                return .continue
+            default:
+                return .continue
             }
-            return .continue
         }
     )
 }
diff --git a/Sources/GraphQL/Validation/ValidationContext.swift b/Sources/GraphQL/Validation/ValidationContext.swift
index 708835e4..a206f7bc 100644
--- a/Sources/GraphQL/Validation/ValidationContext.swift
+++ b/Sources/GraphQL/Validation/ValidationContext.swift
@@ -204,19 +204,22 @@ public final class ValidationContext: ASTValidationContext {
             visitor: visitWithTypeInfo(
                 typeInfo: typeInfo,
                 visitor: Visitor(enter: { node, _, _, _, _ in
-                    if node is VariableDefinition {
+                    switch node.kind {
+                    case .variableDefinition:
                         return .skip
+                    case .variable:
+                        let variable = node as! Variable
+                        usages.append(
+                            VariableUsage(
+                                node: variable,
+                                type: typeInfo.inputType,
+                                defaultValue: typeInfo.defaultValue
+                            )
+                        )
+                        return .continue
+                    default:
+                        return .continue
                     }
-
-                    if let variable = node as? Variable {
-                        usages.append(VariableUsage(
-                            node: variable,
-                            type: typeInfo.inputType,
-                            defaultValue: typeInfo.defaultValue
-                        ))
-                    }
-
-                    return .continue
                 })
             )
         )

From 2545f2a4eb759536bcde55ed45a90b3ed0eab2f9 Mon Sep 17 00:00:00 2001
From: Jay Herron <NeedleInAJayStack@protonmail.com>
Date: Mon, 22 Dec 2025 15:36:19 -0700
Subject: [PATCH 4/6] refactor(perf): Presizes GraphQLFieldDefinitionMap

This improves benchmarked `graphql` time by 5%
---
 Sources/GraphQL/Type/Definition.swift | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Sources/GraphQL/Type/Definition.swift b/Sources/GraphQL/Type/Definition.swift
index 20b15488..52540535 100644
--- a/Sources/GraphQL/Type/Definition.swift
+++ b/Sources/GraphQL/Type/Definition.swift
@@ -351,7 +351,7 @@ extension GraphQLObjectType: Hashable {
 }
 
 func defineFieldMap(name: String, fields: GraphQLFieldMap) throws -> GraphQLFieldDefinitionMap {
-    var fieldMap = GraphQLFieldDefinitionMap()
+    var fieldMap = GraphQLFieldDefinitionMap(minimumCapacity: fields.count)
 
     for (name, config) in fields {
         try assertValid(name: name)

From 771524980e535f65c2788463506291b339caab49 Mon Sep 17 00:00:00 2001
From: Jay Herron <NeedleInAJayStack@protonmail.com>
Date: Mon, 22 Dec 2025 15:56:54 -0700
Subject: [PATCH 5/6] refactor(perf): Adds `fieldCache` and `interfaceCache`

Improves benchmarked `graphql` time by 22%
---
 Sources/GraphQL/Type/Definition.swift | 118 +++++++++++++++++++++-----
 1 file changed, 96 insertions(+), 22 deletions(-)

diff --git a/Sources/GraphQL/Type/Definition.swift b/Sources/GraphQL/Type/Definition.swift
index 52540535..2b125ae5 100644
--- a/Sources/GraphQL/Type/Definition.swift
+++ b/Sources/GraphQL/Type/Definition.swift
@@ -275,10 +275,37 @@ extension GraphQLScalarType: Hashable {
 public final class GraphQLObjectType: @unchecked Sendable {
     public let name: String
     public let description: String?
+
     // While technically not sendable, fields and interfaces should not be mutated after schema
     // creation.
-    public var fields: () throws -> GraphQLFieldMap
-    public var interfaces: () throws -> [GraphQLInterfaceType]
+    public var fields: () throws -> GraphQLFieldMap {
+        get {
+            fieldFunc
+        }
+        set {
+            fieldFunc = newValue
+            // Clear the cache when setting a new function
+            fieldCache = nil
+        }
+    }
+
+    private var fieldFunc: () throws -> GraphQLFieldMap
+    private var fieldCache: GraphQLFieldDefinitionMap?
+
+    public var interfaces: () throws -> [GraphQLInterfaceType] {
+        get {
+            interfaceFunc
+        }
+        set {
+            interfaceFunc = newValue
+            // Clear the cache when setting a new function
+            interfaceCache = nil
+        }
+    }
+
+    private var interfaceFunc: () throws -> [GraphQLInterfaceType]
+    private var interfaceCache: [GraphQLInterfaceType]?
+
     public let isTypeOf: GraphQLIsTypeOf?
     public let astNode: ObjectTypeDefinition?
     public let extensionASTNodes: [TypeExtensionDefinition]
@@ -296,8 +323,8 @@ public final class GraphQLObjectType: @unchecked Sendable {
         try assertValid(name: name)
         self.name = name
         self.description = description
-        self.fields = { fields }
-        self.interfaces = { interfaces }
+        fieldFunc = { fields }
+        interfaceFunc = { interfaces }
         self.isTypeOf = isTypeOf
         self.astNode = astNode
         self.extensionASTNodes = extensionASTNodes
@@ -315,22 +342,32 @@ public final class GraphQLObjectType: @unchecked Sendable {
         try assertValid(name: name)
         self.name = name
         self.description = description
-        self.fields = fields
-        self.interfaces = interfaces
+        fieldFunc = fields
+        interfaceFunc = interfaces
         self.isTypeOf = isTypeOf
         self.astNode = astNode
         self.extensionASTNodes = extensionASTNodes
     }
 
     func getFields() throws -> GraphQLFieldDefinitionMap {
-        try defineFieldMap(
-            name: name,
-            fields: fields()
-        )
+        // Cache on the first call
+        return try fieldCache ?? {
+            let fields = try defineFieldMap(
+                name: name,
+                fields: fields()
+            )
+            self.fieldCache = fields
+            return fields
+        }()
     }
 
     func getInterfaces() throws -> [GraphQLInterfaceType] {
-        return try interfaces()
+        // Cache on the first call
+        return try interfaceCache ?? {
+            let interfaces = try interfaces()
+            self.interfaceCache = interfaces
+            return interfaces
+        }()
     }
 }
 
@@ -657,10 +694,37 @@ public final class GraphQLInterfaceType: @unchecked Sendable {
     public let name: String
     public let description: String?
     public let resolveType: GraphQLTypeResolve?
+
     // While technically not sendable, fields and interfaces should not be mutated after schema
     // creation.
-    public var fields: () throws -> GraphQLFieldMap
-    public var interfaces: () throws -> [GraphQLInterfaceType]
+    public var fields: () throws -> GraphQLFieldMap {
+        get {
+            fieldFunc
+        }
+        set {
+            fieldFunc = newValue
+            // Clear the cache when setting a new function
+            fieldCache = nil
+        }
+    }
+
+    private var fieldFunc: () throws -> GraphQLFieldMap
+    private var fieldCache: GraphQLFieldDefinitionMap?
+
+    public var interfaces: () throws -> [GraphQLInterfaceType] {
+        get {
+            interfaceFunc
+        }
+        set {
+            interfaceFunc = newValue
+            // Clear the cache when setting a new function
+            interfaceCache = nil
+        }
+    }
+
+    private var interfaceFunc: () throws -> [GraphQLInterfaceType]
+    private var interfaceCache: [GraphQLInterfaceType]?
+
     public let astNode: InterfaceTypeDefinition?
     public let extensionASTNodes: [InterfaceExtensionDefinition]
     public let kind: TypeKind = .interface
@@ -677,8 +741,8 @@ public final class GraphQLInterfaceType: @unchecked Sendable {
         try assertValid(name: name)
         self.name = name
         self.description = description
-        self.fields = { fields }
-        self.interfaces = { interfaces }
+        fieldFunc = { fields }
+        interfaceFunc = { interfaces }
         self.resolveType = resolveType
         self.astNode = astNode
         self.extensionASTNodes = extensionASTNodes
@@ -696,22 +760,32 @@ public final class GraphQLInterfaceType: @unchecked Sendable {
         try assertValid(name: name)
         self.name = name
         self.description = description
-        self.fields = fields
-        self.interfaces = interfaces
+        fieldFunc = fields
+        interfaceFunc = interfaces
         self.resolveType = resolveType
         self.astNode = astNode
         self.extensionASTNodes = extensionASTNodes
     }
 
     func getFields() throws -> GraphQLFieldDefinitionMap {
-        try defineFieldMap(
-            name: name,
-            fields: fields()
-        )
+        // Cache on the first call
+        return try fieldCache ?? {
+            let fields = try defineFieldMap(
+                name: name,
+                fields: fields()
+            )
+            self.fieldCache = fields
+            return fields
+        }()
     }
 
     func getInterfaces() throws -> [GraphQLInterfaceType] {
-        return try interfaces()
+        // Cache on the first call
+        return try interfaceCache ?? {
+            let interfaces = try interfaces()
+            self.interfaceCache = interfaces
+            return interfaces
+        }()
     }
 }
 

From 0446903459275a710ebaa655d5b5014329099f5b Mon Sep 17 00:00:00 2001
From: Jay Herron <NeedleInAJayStack@protonmail.com>
Date: Tue, 23 Dec 2025 12:06:20 -0600
Subject: [PATCH 6/6] refactor(perf): Use `first` instead of `filter`

Reduces benchmark `graphql` time by 4%
---
 Sources/GraphQL/Execution/Execute.swift     | 5 +----
 Sources/GraphQL/SwiftUtilities/Mirror.swift | 2 +-
 2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/Sources/GraphQL/Execution/Execute.swift b/Sources/GraphQL/Execution/Execute.swift
index b0a21f8f..e058ebcd 100644
--- a/Sources/GraphQL/Execution/Execute.swift
+++ b/Sources/GraphQL/Execution/Execute.swift
@@ -1057,10 +1057,7 @@ func defaultResolve(
     }
 
     let mirror = Mirror(reflecting: source)
-    guard let value = mirror.getValue(named: info.fieldName) else {
-        return nil
-    }
-    return value
+    return mirror.getValue(named: info.fieldName)
 }
 
 /**
diff --git a/Sources/GraphQL/SwiftUtilities/Mirror.swift b/Sources/GraphQL/SwiftUtilities/Mirror.swift
index c6c26b49..47cca3d4 100644
--- a/Sources/GraphQL/SwiftUtilities/Mirror.swift
+++ b/Sources/GraphQL/SwiftUtilities/Mirror.swift
@@ -16,7 +16,7 @@ func unwrap(_ value: any Sendable) -> (any Sendable)? {
 
 extension Mirror {
     func getValue(named key: String) -> (any Sendable)? {
-        guard let matched = children.filter({ $0.label == key }).first else {
+        guard let matched = children.first(where: { $0.label == key }) else {
             return nil
         }