diff --git a/CodeGeneration/Sources/SyntaxSupport/AttributeNodes.swift b/CodeGeneration/Sources/SyntaxSupport/AttributeNodes.swift
index b7a9dbe5bea..b2957c3a83a 100644
--- a/CodeGeneration/Sources/SyntaxSupport/AttributeNodes.swift
+++ b/CodeGeneration/Sources/SyntaxSupport/AttributeNodes.swift
@@ -13,7 +13,6 @@
 public let ATTRIBUTE_NODES: [Node] = [
   Node(
     kind: .attributeList,
-    base: .syntaxCollection,
     nameForDiagnostics: "attributes",
     documentation: """
       A list of attributes that can be attached to a declaration.
@@ -34,7 +33,6 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .attribute,
-    base: .syntax,
     nameForDiagnostics: "attribute",
     documentation: "An `@` attribute.",
     parserFunction: "parseAttribute",
@@ -161,7 +159,6 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .specializeAvailabilityArgument,
-    base: .syntax,
     nameForDiagnostics: "availability entry",
     documentation: "The availability argument for the _specialize attribute",
     children: [
@@ -195,7 +192,6 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .platformVersionItem,
-    base: .syntax,
     nameForDiagnostics: "version",
     documentation: "A single platform/version pair in an attribute, e.g. `iOS 10.1`.",
     traits: ["WithTrailingComma"],
@@ -217,14 +213,12 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .platformVersionItemList,
-    base: .syntaxCollection,
     nameForDiagnostics: "version list",
     elementChoices: [.platformVersionItem]
   ),
 
   Node(
     kind: .backDeployedAttributeArguments,
-    base: .syntax,
     nameForDiagnostics: "'@backDeployed' arguments",
     documentation: "A collection of arguments for the `@backDeployed` attribute",
     children: [
@@ -253,7 +247,6 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .conventionAttributeArguments,
-    base: .syntax,
     nameForDiagnostics: "@convention(...) arguments",
     documentation: "The arguments for the '@convention(...)'.",
     children: [
@@ -287,7 +280,6 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .conventionWitnessMethodAttributeArguments,
-    base: .syntax,
     nameForDiagnostics: "@convention(...) arguments for witness methods",
     documentation: "The arguments for the '@convention(witness_method: ...)'.",
     children: [
@@ -312,7 +304,6 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .derivativeAttributeArguments,
-    base: .syntax,
     nameForDiagnostics: "attribute arguments",
     documentation:
       "The arguments for the '@derivative(of:)' and '@transpose(of:)' attributes: the 'of:' label, the original declaration name, and an optional differentiability parameter list.",
@@ -361,14 +352,12 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .differentiabilityArgumentList,
-    base: .syntaxCollection,
     nameForDiagnostics: "differentiability parameters",
     elementChoices: [.differentiabilityArgument]
   ),
 
   Node(
     kind: .differentiabilityArgument,
-    base: .syntax,
     nameForDiagnostics: "differentiability argument",
     documentation:
       "A differentiability argument: either the \"self\" identifier, a function parameter name, or a function parameter index.",
@@ -391,7 +380,6 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .differentiabilityWithRespectToArgument,
-    base: .syntax,
     nameForDiagnostics: "'@differentiable' argument",
     documentation: "A clause containing differentiability parameters.",
     children: [
@@ -427,7 +415,6 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .differentiabilityArguments,
-    base: .syntax,
     nameForDiagnostics: "differentiability arguments",
     documentation: "The differentiability arguments.",
     children: [
@@ -450,7 +437,6 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .differentiableAttributeArguments,
-    base: .syntax,
     nameForDiagnostics: "'@differentiable' arguments",
     documentation:
       "The arguments for the `@differentiable` attribute: an optional differentiability kind, an optional differentiability parameter clause, and an optional 'where' clause.",
@@ -496,7 +482,6 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .documentationAttributeArgument,
-    base: .syntax,
     nameForDiagnostics: "@_documentation argument",
     traits: [
       "WithTrailingComma"
@@ -542,7 +527,6 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .documentationAttributeArgumentList,
-    base: .syntaxCollection,
     nameForDiagnostics: "@_documentation arguments",
     documentation: "The arguments of the '@_documentation' attribute",
     elementChoices: [.documentationAttributeArgument]
@@ -550,7 +534,6 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .dynamicReplacementAttributeArguments,
-    base: .syntax,
     nameForDiagnostics: "@_dynamicReplacement argument",
     documentation: "The arguments for the '@_dynamicReplacement' attribute",
     children: [
@@ -572,7 +555,6 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .effectsAttributeArgumentList,
-    base: .syntaxCollection,
     nameForDiagnostics: "@_effects arguments",
     documentation: "The arguments of the '@_effects' attribute. These will be parsed during the SIL stage.",
     elementChoices: [.token]
@@ -580,7 +562,6 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .exposeAttributeArguments,
-    base: .syntax,
     nameForDiagnostics: "@_expose arguments",
     documentation: "The arguments for the '@_expose' attribute",
     children: [
@@ -603,7 +584,6 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .implementsAttributeArguments,
-    base: .syntax,
     nameForDiagnostics: "@_implements arguemnts",
     documentation:
       "The arguments for the `@_implements` attribute of the form `Type, methodName(arg1Label:arg2Label:)`",
@@ -631,7 +611,6 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .labeledSpecializeArgument,
-    base: .syntax,
     nameForDiagnostics: "attribute argument",
     documentation: "A labeled argument for the `@_specialize` attribute like `exported: true`",
     traits: [
@@ -673,7 +652,6 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .objCSelectorPiece,
-    base: .syntax,
     nameForDiagnostics: "Objective-C selector piece",
     documentation:
       "A piece of an Objective-C selector. Either consisting of just an identifier for a nullary selector, an identifier and a colon for a labeled argument or just a colon for an unlabeled argument",
@@ -696,14 +674,12 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .objCSelectorPieceList,
-    base: .syntaxCollection,
     nameForDiagnostics: "Objective-C selector",
     elementChoices: [.objCSelectorPiece]
   ),
 
   Node(
     kind: .opaqueReturnTypeOfAttributeArguments,
-    base: .syntax,
     nameForDiagnostics: "opaque return type arguments",
     documentation: "The arguments for the '@_opaqueReturnTypeOf()'.",
     children: [
@@ -726,7 +702,6 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .originallyDefinedInAttributeArguments,
-    base: .syntax,
     nameForDiagnostics: "@_originallyDefinedIn arguments",
     documentation: "The arguments for the '@_originallyDefinedIn' attribute",
     children: [
@@ -755,7 +730,6 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .specializeAttributeArgumentList,
-    base: .syntaxCollection,
     nameForDiagnostics: "argument to '@_specialize",
     documentation: "A collection of arguments for the `@_specialize` attribute",
     elementChoices: [
@@ -766,7 +740,6 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .specializeTargetFunctionArgument,
-    base: .syntax,
     nameForDiagnostics: "attribute argument",
     documentation:
       "A labeled argument for the `@_specialize` attribute with a function decl value like `target: myFunc(_:)`",
@@ -804,7 +777,6 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .unavailableFromAsyncAttributeArguments,
-    base: .syntax,
     nameForDiagnostics: "@_unavailableFromAsync argument",
     documentation: "The arguments for the '@_unavailableFromAsync' attribute",
     children: [
@@ -825,7 +797,6 @@ public let ATTRIBUTE_NODES: [Node] = [
 
   Node(
     kind: .underscorePrivateAttributeArguments,
-    base: .syntax,
     nameForDiagnostics: "@_private argument",
     documentation: "The arguments for the '@_private' attribute",
     children: [
diff --git a/CodeGeneration/Sources/SyntaxSupport/AvailabilityNodes.swift b/CodeGeneration/Sources/SyntaxSupport/AvailabilityNodes.swift
index f7d12324a79..d787b8761f7 100644
--- a/CodeGeneration/Sources/SyntaxSupport/AvailabilityNodes.swift
+++ b/CodeGeneration/Sources/SyntaxSupport/AvailabilityNodes.swift
@@ -13,7 +13,6 @@
 public let AVAILABILITY_NODES: [Node] = [
   Node(
     kind: .availabilityArgument,
-    base: .syntax,
     nameForDiagnostics: "availability argument",
     documentation:
       "A single argument to an `@available` argument like `*`, `iOS 10.1`, or `message: \"This has been deprecated\"`.",
@@ -53,7 +52,6 @@ public let AVAILABILITY_NODES: [Node] = [
 
   Node(
     kind: .availabilityLabeledArgument,
-    base: .syntax,
     nameForDiagnostics: "availability argument",
     documentation:
       "An argument to an `@available` attribute that consists of a label and a value, e.g. `message: \"This has been deprecated\"`.",
@@ -95,14 +93,12 @@ public let AVAILABILITY_NODES: [Node] = [
 
   Node(
     kind: .availabilityArgumentList,
-    base: .syntaxCollection,
     nameForDiagnostics: "'@availability' arguments",
     elementChoices: [.availabilityArgument]
   ),
 
   Node(
     kind: .platformVersion,
-    base: .syntax,
     nameForDiagnostics: "version restriction",
     documentation:
       "An argument to `@available` that restricts the availability on a certain platform to a version, e.g. `iOS 10` or `swift 3.4`.",
@@ -132,7 +128,6 @@ public let AVAILABILITY_NODES: [Node] = [
 
   Node(
     kind: .versionComponent,
-    base: .syntax,
     nameForDiagnostics: nil,
     documentation: "An element to represent a single component in a version, like `.1`.",
     children: [
@@ -151,14 +146,12 @@ public let AVAILABILITY_NODES: [Node] = [
 
   Node(
     kind: .versionComponentList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.versionComponent]
   ),
 
   Node(
     kind: .versionTuple,
-    base: .syntax,
     nameForDiagnostics: "version tuple",
     documentation:
       "A version number like `1.2.0`. Only the first version component is required. There might be an arbitrary number of following components.",
diff --git a/CodeGeneration/Sources/SyntaxSupport/CommonNodes.swift b/CodeGeneration/Sources/SyntaxSupport/CommonNodes.swift
index 7247e17a909..00046d57019 100644
--- a/CodeGeneration/Sources/SyntaxSupport/CommonNodes.swift
+++ b/CodeGeneration/Sources/SyntaxSupport/CommonNodes.swift
@@ -13,14 +13,12 @@
 public let COMMON_NODES: [Node] = [
   Node(
     kind: .codeBlockItemList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.codeBlockItem]
   ),
 
   Node(
     kind: .codeBlockItem,
-    base: .syntax,
     nameForDiagnostics: nil,
     documentation: "A CodeBlockItem is any Syntax node that appears on its own line inside a CodeBlock.",
     parserFunction: "parseNonOptionalCodeBlockItem",
@@ -54,7 +52,6 @@ public let COMMON_NODES: [Node] = [
 
   Node(
     kind: .codeBlock,
-    base: .syntax,
     nameForDiagnostics: "code block",
     parserFunction: "parseCodeBlock",
     traits: [
@@ -82,7 +79,6 @@ public let COMMON_NODES: [Node] = [
 
   Node(
     kind: .throwsClause,
-    base: .syntax,
     nameForDiagnostics: "throws clause",
     children: [
       Child(
@@ -114,7 +110,6 @@ public let COMMON_NODES: [Node] = [
 
   Node(
     kind: .accessorEffectSpecifiers,
-    base: .syntax,
     nameForDiagnostics: "accessor specifiers",
     traits: [
       "EffectSpecifiers"
@@ -137,7 +132,6 @@ public let COMMON_NODES: [Node] = [
 
   Node(
     kind: .functionEffectSpecifiers,
-    base: .syntax,
     nameForDiagnostics: "effect specifiers",
     traits: [
       "EffectSpecifiers"
@@ -160,7 +154,6 @@ public let COMMON_NODES: [Node] = [
 
   Node(
     kind: .deinitializerEffectSpecifiers,
-    base: .syntax,
     nameForDiagnostics: "effect specifiers",
     traits: [],
     children: [
@@ -175,21 +168,18 @@ public let COMMON_NODES: [Node] = [
 
   Node(
     kind: .decl,
-    base: .syntax,
     nameForDiagnostics: "declaration",
     parserFunction: "parseDeclaration"
   ),
 
   Node(
     kind: .expr,
-    base: .syntax,
     nameForDiagnostics: "expression",
     parserFunction: "parseExpression"
   ),
 
   Node(
     kind: .missingDecl,
-    base: .decl,
     nameForDiagnostics: "declaration",
     documentation:
       "In case the source code is missing a declaration, this node stands in place of the missing declaration.",
@@ -225,7 +215,6 @@ public let COMMON_NODES: [Node] = [
 
   Node(
     kind: .missingExpr,
-    base: .expr,
     nameForDiagnostics: "expression",
     documentation:
       "In case the source code is missing an expression, this node stands in place of the missing expression.",
@@ -247,7 +236,6 @@ public let COMMON_NODES: [Node] = [
 
   Node(
     kind: .missingPattern,
-    base: .pattern,
     nameForDiagnostics: "pattern",
     documentation: "In case the source code is missing a pattern, this node stands in place of the missing pattern.",
     traits: [
@@ -268,7 +256,6 @@ public let COMMON_NODES: [Node] = [
 
   Node(
     kind: .missingStmt,
-    base: .stmt,
     nameForDiagnostics: "statement",
     documentation:
       "In case the source code is missing a statement, this node stands in place of the missing statement.",
@@ -290,7 +277,6 @@ public let COMMON_NODES: [Node] = [
 
   Node(
     kind: .missing,
-    base: .syntax,
     nameForDiagnostics: nil,
     documentation: "In case the source code is missing a syntax node, this node stands in place of the missing node.",
     traits: [
@@ -311,7 +297,6 @@ public let COMMON_NODES: [Node] = [
 
   Node(
     kind: .missingType,
-    base: .type,
     nameForDiagnostics: "type",
     documentation: "In case the source code is missing a type, this node stands in place of the missing type.",
     traits: [
@@ -332,21 +317,18 @@ public let COMMON_NODES: [Node] = [
 
   Node(
     kind: .pattern,
-    base: .syntax,
     nameForDiagnostics: "pattern",
     parserFunction: "parsePattern"
   ),
 
   Node(
     kind: .stmt,
-    base: .syntax,
     nameForDiagnostics: "statement",
     parserFunction: "parseStatement"
   ),
 
   Node(
     kind: .typeEffectSpecifiers,
-    base: .syntax,
     nameForDiagnostics: "effect specifiers",
     traits: [
       "EffectSpecifiers"
@@ -368,14 +350,12 @@ public let COMMON_NODES: [Node] = [
 
   Node(
     kind: .type,
-    base: .syntax,
     nameForDiagnostics: "type",
     parserFunction: "parseType"
   ),
 
   Node(
     kind: .unexpectedNodes,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     documentation:
       "A collection of syntax nodes that occurred in the source code but could not be used to form a valid syntax tree.",
diff --git a/CodeGeneration/Sources/SyntaxSupport/DeclNodes.swift b/CodeGeneration/Sources/SyntaxSupport/DeclNodes.swift
index 53f430923fe..73485630746 100644
--- a/CodeGeneration/Sources/SyntaxSupport/DeclNodes.swift
+++ b/CodeGeneration/Sources/SyntaxSupport/DeclNodes.swift
@@ -13,7 +13,6 @@
 public let DECL_NODES: [Node] = [
   Node(
     kind: .importPathComponent,
-    base: .syntax,
     nameForDiagnostics: nil,
     children: [
       Child(
@@ -37,14 +36,12 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .importPathComponentList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.importPathComponent]
   ),
 
   Node(
     kind: .accessorBlock,
-    base: .syntax,
     nameForDiagnostics: nil,
     parserFunction: "parseAccessorBlock",
     traits: [
@@ -79,7 +76,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .accessorDecl,
-    base: .decl,
     nameForDiagnostics: "accessor",
     parserFunction: "parseAccessorDecl",
     traits: [
@@ -139,14 +135,12 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .accessorDeclList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.accessorDecl]
   ),
 
   Node(
     kind: .accessorParameters,
-    base: .syntax,
     nameForDiagnostics: nil,
     traits: [
       "Parenthesized"
@@ -170,7 +164,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .actorDecl,
-    base: .decl,
     nameForDiagnostics: "actor",
     traits: [
       "DeclGroup",
@@ -232,7 +225,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .associatedTypeDecl,
-    base: .decl,
     nameForDiagnostics: "associatedtype declaration",
     documentation: """
       An `associatedtype` declaration
@@ -316,7 +308,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .classDecl,
-    base: .decl,
     nameForDiagnostics: "class",
     documentation: """
       A `class` declaration
@@ -406,7 +397,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .declModifierDetail,
-    base: .syntax,
     nameForDiagnostics: nil,
     traits: [
       "Parenthesized"
@@ -429,7 +419,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .declModifier,
-    base: .syntax,
     nameForDiagnostics: "modifier",
     children: [
       Child(
@@ -483,7 +472,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .deinitializerDecl,
-    base: .decl,
     nameForDiagnostics: "deinitializer",
     documentation: """
       A `deint` declaration
@@ -534,7 +522,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .designatedType,
-    base: .syntax,
     nameForDiagnostics: nil,
     children: [
       Child(
@@ -550,14 +537,12 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .designatedTypeList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.designatedType]
   ),
 
   Node(
     kind: .editorPlaceholderDecl,
-    base: .decl,
     nameForDiagnostics: "editor placeholder",
     documentation: """
       An editor placeholder, e.g. `<#declaration#>` that is used in a position that expects a declaration.
@@ -594,7 +579,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .enumCaseParameterClause,
-    base: .syntax,
     nameForDiagnostics: "parameter clause",
     traits: [
       "Parenthesized"
@@ -622,14 +606,12 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .enumCaseParameterList,
-    base: .syntaxCollection,
     nameForDiagnostics: "parameter list",
     elementChoices: [.enumCaseParameter]
   ),
 
   Node(
     kind: .enumCaseParameter,
-    base: .syntax,
     nameForDiagnostics: "parameter",
     parserFunction: "parseEnumCaseParameter",
     traits: ["WithTrailingComma", "WithModifiers"],
@@ -680,7 +662,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .enumCaseDecl,
-    base: .decl,
     nameForDiagnostics: "enum case",
     documentation:
       "A `case` declaration of a Swift `enum`. It can have 1 or more `EnumCaseElement`s inside, each declaring a different case of the enum.",
@@ -717,7 +698,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .enumCaseElementList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     documentation: "A collection of 0 or more ``EnumCaseElementSyntax``s.",
     elementChoices: [.enumCaseElement]
@@ -725,7 +705,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .enumCaseElement,
-    base: .syntax,
     nameForDiagnostics: nil,
     documentation:
       "An element of an enum case, containing the name of the case and, optionally, either associated values or an assignment to a raw value.",
@@ -764,7 +743,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .enumDecl,
-    base: .decl,
     nameForDiagnostics: "enum",
     documentation: "A Swift `enum` declaration.",
     traits: [
@@ -832,7 +810,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .extensionDecl,
-    base: .decl,
     nameForDiagnostics: "extension",
     documentation: """
         An `extension` declaration.
@@ -911,7 +888,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .functionDecl,
-    base: .decl,
     nameForDiagnostics: "function",
     documentation: """
         A Swift `func` declaration.
@@ -1004,7 +980,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .functionParameterList,
-    base: .syntaxCollection,
     nameForDiagnostics: "parameter list",
     documentation: """
       A list of function parameters that are type annotated and a label.
@@ -1023,7 +998,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .functionParameter,
-    base: .syntax,
     nameForDiagnostics: "parameter",
     documentation: "A function parameter",
     parserFunction: "parseFunctionParameter",
@@ -1090,7 +1064,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .functionSignature,
-    base: .syntax,
     nameForDiagnostics: "function signature",
     documentation: "A function signature that defines the interface of the function.",
     children: [
@@ -1118,14 +1091,12 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .ifConfigClauseList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.ifConfigClause]
   ),
 
   Node(
     kind: .ifConfigClause,
-    base: .syntax,
     nameForDiagnostics: "conditional compilation clause",
     children: [
       Child(
@@ -1169,7 +1140,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .ifConfigDecl,
-    base: .decl,
     nameForDiagnostics: "conditional compilation block",
     children: [
       Child(
@@ -1185,7 +1155,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .importDecl,
-    base: .decl,
     nameForDiagnostics: "import",
     documentation: """
       An `import` declaration
@@ -1251,14 +1220,12 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .inheritedTypeList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.inheritedType]
   ),
 
   Node(
     kind: .inheritedType,
-    base: .syntax,
     nameForDiagnostics: "inherited type",
     traits: [
       "WithTrailingComma"
@@ -1279,7 +1246,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .initializerClause,
-    base: .syntax,
     nameForDiagnostics: nil,
     children: [
       Child(
@@ -1295,7 +1261,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .initializerDecl,
-    base: .decl,
     nameForDiagnostics: "initializer",
     documentation: """
       An `init` declaration
@@ -1374,7 +1339,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .macroDecl,
-    base: .decl,
     nameForDiagnostics: "macro",
     traits: [
       "NamedDecl",
@@ -1433,7 +1397,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .macroExpansionDecl,
-    base: .decl,
     nameForDiagnostics: "macro expansion",
     documentation: "The expansion of a freestanding macro in a position that expects a declaration.",
     traits: [
@@ -1502,7 +1465,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .memberBlock,
-    base: .syntax,
     nameForDiagnostics: "member block",
     parserFunction: "parseMemberBlock",
     traits: ["Braced"],
@@ -1524,7 +1486,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .memberBlockItem,
-    base: .syntax,
     nameForDiagnostics: nil,
     documentation: "A member declaration of a type consisting of a declaration and an optional semicolon;",
     children: [
@@ -1544,21 +1505,18 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .memberBlockItemList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.memberBlockItem]
   ),
 
   Node(
     kind: .declModifierList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.declModifier]
   ),
 
   Node(
     kind: .operatorDecl,
-    base: .decl,
     nameForDiagnostics: "operator declaration",
     documentation: "A Swift `operator` declaration.",
     traits: [
@@ -1592,7 +1550,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .operatorPrecedenceAndTypes,
-    base: .syntax,
     nameForDiagnostics: nil,
     documentation:
       "A clause to specify precedence group in infix operator declarations, and designated types in any operator declaration.",
@@ -1617,7 +1574,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .functionParameterClause,
-    base: .syntax,
     nameForDiagnostics: "parameter clause",
     traits: [
       "Parenthesized"
@@ -1642,14 +1598,12 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .patternBindingList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.patternBinding]
   ),
 
   Node(
     kind: .patternBinding,
-    base: .syntax,
     nameForDiagnostics: nil,
     documentation: """
       Defines variables inside a variable declaration.
@@ -1713,7 +1667,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .poundSourceLocationArguments,
-    base: .syntax,
     nameForDiagnostics: "'#sourceLocation' arguments",
     children: [
       Child(
@@ -1755,7 +1708,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .poundSourceLocation,
-    base: .decl,
     nameForDiagnostics: "'#sourceLocation' directive",
     traits: [
       "Parenthesized"
@@ -1785,7 +1737,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .precedenceGroupAssignment,
-    base: .syntax,
     nameForDiagnostics: "'assignment' property of precedencegroup",
     documentation: "Specifies the precedence of an operator when used in an operation that includes optional chaining.",
     children: [
@@ -1810,7 +1761,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .precedenceGroupAssociativity,
-    base: .syntax,
     nameForDiagnostics: "'associativity' property of precedencegroup",
     documentation:
       "Specifies how a sequence of operators with the same precedence level are grouped together in the absence of grouping parentheses.",
@@ -1834,14 +1784,12 @@ public let DECL_NODES: [Node] = [
   ),
   Node(
     kind: .precedenceGroupAttributeList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.precedenceGroupRelation, .precedenceGroupAssignment, .precedenceGroupAssociativity]
   ),
 
   Node(
     kind: .precedenceGroupDecl,
-    base: .decl,
     nameForDiagnostics: "precedencegroup",
     documentation: "A Swift `precedencegroup` declaration.",
     traits: [
@@ -1891,7 +1839,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .precedenceGroupName,
-    base: .syntax,
     nameForDiagnostics: nil,
     traits: ["WithTrailingComma"],
     children: [
@@ -1910,14 +1857,12 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .precedenceGroupNameList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.precedenceGroupName]
   ),
 
   Node(
     kind: .precedenceGroupRelation,
-    base: .syntax,
     nameForDiagnostics: "'relation' property of precedencegroup",
     documentation: "Specify the new precedence group's relation to existing precedence groups.",
     children: [
@@ -1942,7 +1887,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .protocolDecl,
-    base: .decl,
     nameForDiagnostics: "protocol",
     documentation: """
       A `protocol` declaration
@@ -2016,7 +1960,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .returnClause,
-    base: .syntax,
     nameForDiagnostics: nil,
     children: [
       Child(
@@ -2036,7 +1979,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .sourceFile,
-    base: .syntax,
     nameForDiagnostics: "source file",
     parserFunction: "parseSourceFile",
     traits: ["WithStatements"],
@@ -2061,7 +2003,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .structDecl,
-    base: .decl,
     nameForDiagnostics: "struct",
     documentation: """
       A `struct` declaration
@@ -2187,7 +2128,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .subscriptDecl,
-    base: .decl,
     nameForDiagnostics: "subscript",
     traits: [
       "WithAttributes",
@@ -2245,7 +2185,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .inheritanceClause,
-    base: .syntax,
     nameForDiagnostics: "inheritance clause",
     children: [
       Child(
@@ -2262,7 +2201,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .typeInitializerClause,
-    base: .syntax,
     nameForDiagnostics: nil,
     children: [
       Child(
@@ -2279,7 +2217,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .typeAliasDecl,
-    base: .decl,
     nameForDiagnostics: "typealias declaration",
     traits: [
       "NamedDecl",
@@ -2331,7 +2268,6 @@ public let DECL_NODES: [Node] = [
 
   Node(
     kind: .variableDecl,
-    base: .decl,
     nameForDiagnostics: "variable",
     documentation: """
       Declaration of one or more variables
diff --git a/CodeGeneration/Sources/SyntaxSupport/ExprNodes.swift b/CodeGeneration/Sources/SyntaxSupport/ExprNodes.swift
index c642bf81efb..6497aa0a3e6 100644
--- a/CodeGeneration/Sources/SyntaxSupport/ExprNodes.swift
+++ b/CodeGeneration/Sources/SyntaxSupport/ExprNodes.swift
@@ -13,14 +13,12 @@
 public let EXPR_NODES: [Node] = [
   Node(
     kind: .arrayElementList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.arrayElement]
   ),
 
   Node(
     kind: .arrayElement,
-    base: .syntax,
     nameForDiagnostics: "array element",
     documentation: "An element inside an array literal.",
     traits: [
@@ -42,7 +40,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .arrayExpr,
-    base: .expr,
     nameForDiagnostics: "array",
     documentation: "An array literal.",
     children: [
@@ -65,7 +62,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .arrowExpr,
-    base: .expr,
     nameForDiagnostics: nil,
     documentation: """
       The arrow when a type is used at a position that syntactically expectes an expression.
@@ -94,7 +90,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .asExpr,
-    base: .expr,
     nameForDiagnostics: "'as'",
     documentation: """
       The cast of an expressison to a different type.
@@ -137,7 +132,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .assignmentExpr,
-    base: .expr,
     nameForDiagnostics: nil,
     children: [
       Child(
@@ -150,7 +144,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .awaitExpr,
-    base: .expr,
     nameForDiagnostics: "'await' expression",
     children: [
       Child(
@@ -166,7 +159,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .binaryOperatorExpr,
-    base: .expr,
     nameForDiagnostics: "operator",
     documentation: """
       An operator like `+` or `-`.
@@ -186,7 +178,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .booleanLiteralExpr,
-    base: .expr,
     nameForDiagnostics: "bool literal",
     children: [
       Child(
@@ -199,7 +190,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .borrowExpr,
-    base: .expr,
     nameForDiagnostics: "'_borrow' expression",
     children: [
       Child(
@@ -215,7 +205,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: ._canImportExpr,
-    base: .expr,
     nameForDiagnostics: "'canImport' expression",
     children: [
       Child(
@@ -244,7 +233,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: ._canImportVersionInfo,
-    base: .expr,
     nameForDiagnostics: nil,
     children: [
       Child(
@@ -269,7 +257,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .switchCaseItem,
-    base: .syntax,
     nameForDiagnostics: nil,
     traits: [
       "WithTrailingComma"
@@ -294,14 +281,12 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .closureCaptureList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.closureCapture]
   ),
 
   Node(
     kind: .closureCaptureSpecifier,
-    base: .syntax,
     nameForDiagnostics: "closure capture specifier",
     children: [
       Child(
@@ -328,7 +313,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .closureCapture,
-    base: .syntax,
     nameForDiagnostics: "closure capture",
     traits: [
       "WithTrailingComma"
@@ -358,7 +342,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .closureCaptureClause,
-    base: .syntax,
     nameForDiagnostics: "closure capture clause",
     children: [
       Child(
@@ -378,7 +361,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .closureParameter,
-    base: .syntax,
     nameForDiagnostics: "parameter",
     parserFunction: "parseClosureParameter",
     traits: ["WithTrailingComma", "WithAttributes", "WithModifiers"],
@@ -435,14 +417,12 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .closureParameterList,
-    base: .syntaxCollection,
     nameForDiagnostics: "parameter list",
     elementChoices: [.closureParameter]
   ),
 
   Node(
     kind: .closureParameterClause,
-    base: .syntax,
     nameForDiagnostics: "parameter clause",
     traits: [
       "Parenthesized"
@@ -470,7 +450,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .closureExpr,
-    base: .expr,
     nameForDiagnostics: "closure",
     traits: [
       "Braced",
@@ -499,7 +478,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .closureShorthandParameterList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     documentation: """
       A list of closure parameters that are not parenthesized and don't have type annotations.
@@ -520,7 +498,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .closureShorthandParameter,
-    base: .syntax,
     nameForDiagnostics: "closure parameter",
     traits: [
       "WithTrailingComma"
@@ -541,7 +518,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .closureSignature,
-    base: .syntax,
     nameForDiagnostics: "closure signature",
     traits: [
       "WithAttributes"
@@ -594,14 +570,12 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .declNameArgumentList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.declNameArgument]
   ),
 
   Node(
     kind: .declNameArgument,
-    base: .syntax,
     nameForDiagnostics: nil,
     children: [
       Child(
@@ -617,7 +591,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .declNameArguments,
-    base: .syntax,
     nameForDiagnostics: nil,
     traits: [
       "Parenthesized"
@@ -640,14 +613,12 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .dictionaryElementList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.dictionaryElement]
   ),
 
   Node(
     kind: .dictionaryElement,
-    base: .syntax,
     nameForDiagnostics: "dictionary element",
     documentation: "An element inside a dictionary literal.",
     traits: [
@@ -680,7 +651,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .dictionaryExpr,
-    base: .expr,
     nameForDiagnostics: "dictionary",
     documentation: "A dictionary literal",
     children: [
@@ -710,7 +680,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .discardAssignmentExpr,
-    base: .expr,
     nameForDiagnostics: nil,
     documentation: """
       A `_` that discards a value inside an assignment.
@@ -736,7 +705,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .doExpr,
-    base: .expr,
     experimentalFeature: .doExpressions,
     nameForDiagnostics: "'do' block",
     documentation: """
@@ -784,7 +752,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .editorPlaceholderExpr,
-    base: .expr,
     nameForDiagnostics: "editor placeholder",
     documentation: """
       - Warning: This ``EditorPlaceholderExprSyntax`` node is not generated by the parser anymore. Placeholders are represented by a ``DeclReferenceExprSyntax``.
@@ -800,7 +767,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .exprList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     documentation: "A list of expressions connected by operators. This list is contained by a ``SequenceExprSyntax``.",
     elementChoices: [.expr]
@@ -808,7 +774,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .expressionSegment,
-    base: .syntax,
     nameForDiagnostics: nil,
     documentation: """
       An interpolated expression inside a string literal.
@@ -846,7 +811,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .floatLiteralExpr,
-    base: .expr,
     nameForDiagnostics: "floating literal",
     children: [
       Child(
@@ -859,7 +823,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .forceUnwrapExpr,
-    base: .expr,
     nameForDiagnostics: "force unwrap",
     children: [
       Child(
@@ -875,7 +838,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .functionCallExpr,
-    base: .expr,
     nameForDiagnostics: "function call",
     children: [
       Child(
@@ -919,7 +881,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .declReferenceExpr,
-    base: .expr,
     nameForDiagnostics: nil,
     children: [
       Child(
@@ -948,7 +909,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .ifExpr,
-    base: .expr,
     nameForDiagnostics: "'if' statement",
     traits: [
       "WithCodeBlock"
@@ -992,7 +952,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .inOutExpr,
-    base: .expr,
     nameForDiagnostics: "inout expression",
     documentation: "An expression prefixed with `&` to pass an argument to an `inout` parameter.",
     children: [
@@ -1009,7 +968,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .infixOperatorExpr,
-    base: .expr,
     nameForDiagnostics: nil,
     documentation: """
       An infix operator call like `1 + 2`.
@@ -1037,7 +995,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .integerLiteralExpr,
-    base: .expr,
     nameForDiagnostics: "integer literal",
     children: [
       Child(
@@ -1050,7 +1007,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .isExpr,
-    base: .expr,
     nameForDiagnostics: "'is'",
     documentation: """
       Checks if an expression is of a given type.
@@ -1088,7 +1044,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .keyPathComponentList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     documentation: "The components of a key path",
     elementChoices: [.keyPathComponent]
@@ -1096,7 +1051,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .keyPathComponent,
-    base: .syntax,
     nameForDiagnostics: "key path component",
     documentation: "A single key path component",
     children: [
@@ -1127,7 +1081,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .keyPathExpr,
-    base: .expr,
     nameForDiagnostics: "key path",
     documentation: #"""
       A key path.
@@ -1158,7 +1111,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .keyPathOptionalComponent,
-    base: .syntax,
     nameForDiagnostics: "key path optional component",
     documentation: "A key path component like `?` or `!`.",
     children: [
@@ -1171,7 +1123,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .keyPathPropertyComponent,
-    base: .syntax,
     nameForDiagnostics: "key path property component",
     documentation: "A key path component like `.property` or `.1`.",
     children: [
@@ -1189,7 +1140,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .keyPathSubscriptComponent,
-    base: .syntax,
     nameForDiagnostics: "key path subscript component",
     documentation: "A key path component like `.[17]`",
     children: [
@@ -1214,7 +1164,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .macroExpansionExpr,
-    base: .expr,
     nameForDiagnostics: "macro expansion",
     documentation: "The expansion of a freestanding macro in a position that expects an expression.",
     traits: [
@@ -1271,7 +1220,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .memberAccessExpr,
-    base: .expr,
     nameForDiagnostics: "member access",
     documentation: "An expression that access a member like a function or a property.",
     children: [
@@ -1298,7 +1246,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .consumeExpr,
-    base: .expr,
     nameForDiagnostics: "'consume' expression",
     children: [
       Child(
@@ -1315,7 +1262,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .copyExpr,
-    base: .expr,
     nameForDiagnostics: "'copy' expression",
     children: [
       Child(
@@ -1331,14 +1277,12 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .multipleTrailingClosureElementList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.multipleTrailingClosureElement]
   ),
 
   Node(
     kind: .multipleTrailingClosureElement,
-    base: .syntax,
     nameForDiagnostics: "trailing closure",
     children: [
       Child(
@@ -1359,7 +1303,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .nilLiteralExpr,
-    base: .expr,
     nameForDiagnostics: nil,
     children: [
       Child(
@@ -1371,7 +1314,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .optionalChainingExpr,
-    base: .expr,
     nameForDiagnostics: "optional chaining",
     children: [
       Child(
@@ -1387,7 +1329,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .packElementExpr,
-    base: .expr,
     nameForDiagnostics: nil,
     documentation: "A pack element expression spelled with `each`.",
     children: [
@@ -1405,7 +1346,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .packExpansionExpr,
-    base: .expr,
     nameForDiagnostics: nil,
     documentation: "A pack expansion expression spelled with `repeat`.",
     children: [
@@ -1423,7 +1363,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .postfixIfConfigExpr,
-    base: .expr,
     nameForDiagnostics: nil,
     children: [
       Child(
@@ -1440,7 +1379,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .postfixOperatorExpr,
-    base: .expr,
     nameForDiagnostics: "postfix expression",
     children: [
       Child(
@@ -1457,7 +1395,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .prefixOperatorExpr,
-    base: .expr,
     nameForDiagnostics: "operator",
     documentation: """
       A prefix operator applied to a value.
@@ -1488,7 +1425,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .regexLiteralExpr,
-    base: .expr,
     nameForDiagnostics: "regex literal",
     children: [
       Child(
@@ -1521,7 +1457,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .sequenceExpr,
-    base: .expr,
     nameForDiagnostics: nil,
     documentation: """
       A flat list of expressions before operator folding using the `SwiftOperators` library.
@@ -1542,7 +1477,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .genericSpecializationExpr,
-    base: .expr,
     nameForDiagnostics: nil,
     children: [
       Child(
@@ -1558,7 +1492,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .stringLiteralExpr,
-    base: .expr,
     nameForDiagnostics: "string literal",
     documentation: #"""
       A string literal.
@@ -1601,14 +1534,12 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .stringLiteralSegmentList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.stringSegment, .expressionSegment]
   ),
 
   Node(
     kind: .simpleStringLiteralExpr,
-    base: .expr,
     nameForDiagnostics: "simple string literal",
     documentation: "A simple string that can’t contain string interpolation and cannot have raw string delimiters.",
     children: [
@@ -1632,7 +1563,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .simpleStringLiteralSegmentList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     documentation: "String literal segments that only can contain non string interpolated or extended escaped strings",
     elementChoices: [.stringSegment]
@@ -1640,7 +1570,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .stringSegment,
-    base: .syntax,
     nameForDiagnostics: nil,
     documentation: """
       A literal segment inside a string segment.
@@ -1657,7 +1586,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .subscriptCallExpr,
-    base: .expr,
     nameForDiagnostics: "subscript",
     children: [
       Child(
@@ -1701,7 +1629,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .superExpr,
-    base: .expr,
     nameForDiagnostics: nil,
     children: [
       Child(
@@ -1713,7 +1640,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .switchCaseLabel,
-    base: .syntax,
     nameForDiagnostics: nil,
     children: [
       Child(
@@ -1733,14 +1659,12 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .switchCaseList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.switchCase, .ifConfigDecl]
   ),
 
   Node(
     kind: .switchCase,
-    base: .syntax,
     nameForDiagnostics: "switch case",
     parserFunction: "parseSwitchCase",
     traits: ["WithStatements"],
@@ -1775,7 +1699,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .switchDefaultLabel,
-    base: .syntax,
     nameForDiagnostics: nil,
     children: [
       Child(
@@ -1791,7 +1714,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .switchExpr,
-    base: .expr,
     nameForDiagnostics: "'switch' statement",
     documentation: """
       A `switch` expression.
@@ -1842,7 +1764,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .ternaryExpr,
-    base: .expr,
     nameForDiagnostics: "ternay expression",
     documentation: """
       The ternary operator with operator precedences resolved.
@@ -1889,7 +1810,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .tryExpr,
-    base: .expr,
     nameForDiagnostics: "'try' expression",
     documentation: """
       An expression prefixed with `try`.
@@ -1927,14 +1847,12 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .labeledExprList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.labeledExpr]
   ),
 
   Node(
     kind: .labeledExpr,
-    base: .syntax,
     nameForDiagnostics: nil,
     documentation: """
       An expression that is prefixed by a label.
@@ -1973,7 +1891,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .tupleExpr,
-    base: .expr,
     nameForDiagnostics: "tuple",
     traits: [
       "Parenthesized"
@@ -1997,7 +1914,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .typeExpr,
-    base: .expr,
     nameForDiagnostics: nil,
     children: [
       Child(
@@ -2009,7 +1925,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .unresolvedAsExpr,
-    base: .expr,
     nameForDiagnostics: "'as'",
     documentation: """
       The `as` keyword without any operands.
@@ -2033,7 +1948,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .unresolvedIsExpr,
-    base: .expr,
     nameForDiagnostics: "'is'",
     documentation: """
       The `is` keyword without any operands.
@@ -2052,7 +1966,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .patternExpr,
-    base: .expr,
     nameForDiagnostics: nil,
     children: [
       Child(
@@ -2064,7 +1977,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .unresolvedTernaryExpr,
-    base: .expr,
     nameForDiagnostics: "ternary operator",
     documentation: """
       The middle section of a ternary operator between `?` and `:`.
@@ -2093,7 +2005,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .yieldedExpression,
-    base: .syntax,
     nameForDiagnostics: nil,
     children: [
       Child(
@@ -2110,7 +2021,6 @@ public let EXPR_NODES: [Node] = [
 
   Node(
     kind: .yieldedExpressionList,
-    base: .syntaxCollection,
     nameForDiagnostics: "yield list",
     elementChoices: [.yieldedExpression]
   ),
diff --git a/CodeGeneration/Sources/SyntaxSupport/GenericNodes.swift b/CodeGeneration/Sources/SyntaxSupport/GenericNodes.swift
index 0b155c0bf01..70d8b0324dd 100644
--- a/CodeGeneration/Sources/SyntaxSupport/GenericNodes.swift
+++ b/CodeGeneration/Sources/SyntaxSupport/GenericNodes.swift
@@ -13,7 +13,6 @@
 public let GENERIC_NODES: [Node] = [
   Node(
     kind: .conformanceRequirement,
-    base: .syntax,
     nameForDiagnostics: "conformance requirement",
     children: [
       Child(
@@ -35,7 +34,6 @@ public let GENERIC_NODES: [Node] = [
 
   Node(
     kind: .genericParameterClause,
-    base: .syntax,
     nameForDiagnostics: "generic parameter clause",
     documentation: "The parameter clause that defines the generic parameters.",
     parserFunction: "parseGenericParameters",
@@ -74,14 +72,12 @@ public let GENERIC_NODES: [Node] = [
 
   Node(
     kind: .genericParameterList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.genericParameter]
   ),
 
   Node(
     kind: .genericParameter,
-    base: .syntax,
     nameForDiagnostics: "generic parameter",
     traits: [
       "WithTrailingComma",
@@ -125,14 +121,12 @@ public let GENERIC_NODES: [Node] = [
 
   Node(
     kind: .genericRequirementList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.genericRequirement]
   ),
 
   Node(
     kind: .genericRequirement,
-    base: .syntax,
     nameForDiagnostics: nil,
     traits: [
       "WithTrailingComma"
@@ -166,7 +160,6 @@ public let GENERIC_NODES: [Node] = [
 
   Node(
     kind: .genericWhereClause,
-    base: .syntax,
     nameForDiagnostics: "'where' clause",
     documentation:
       "A `where` clause that places additional constraints on generic parameters like `where Element: Hashable`.",
@@ -187,7 +180,6 @@ public let GENERIC_NODES: [Node] = [
 
   Node(
     kind: .layoutRequirement,
-    base: .syntax,
     nameForDiagnostics: "layout requirement",
     children: [
       Child(
@@ -247,7 +239,6 @@ public let GENERIC_NODES: [Node] = [
 
   Node(
     kind: .primaryAssociatedTypeClause,
-    base: .syntax,
     nameForDiagnostics: "primary associated type clause",
     children: [
       Child(
@@ -270,14 +261,12 @@ public let GENERIC_NODES: [Node] = [
 
   Node(
     kind: .primaryAssociatedTypeList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.primaryAssociatedType]
   ),
 
   Node(
     kind: .primaryAssociatedType,
-    base: .syntax,
     nameForDiagnostics: nil,
     traits: [
       "WithTrailingComma"
@@ -298,7 +287,6 @@ public let GENERIC_NODES: [Node] = [
 
   Node(
     kind: .sameTypeRequirement,
-    base: .syntax,
     nameForDiagnostics: "same type requirement",
     children: [
       Child(
diff --git a/CodeGeneration/Sources/SyntaxSupport/Node.swift b/CodeGeneration/Sources/SyntaxSupport/Node.swift
index 3205f0425f7..03516b6643e 100644
--- a/CodeGeneration/Sources/SyntaxSupport/Node.swift
+++ b/CodeGeneration/Sources/SyntaxSupport/Node.swift
@@ -38,7 +38,9 @@ public class Node: NodeChoiceConvertible {
   public let kind: SyntaxNodeKind
 
   /// The kind of node’s supertype. This kind must have `isBase == true`
-  public let base: SyntaxNodeKind
+  public var base: SyntaxNodeKind {
+    self.kind.base
+  }
 
   public let experimentalFeature: ExperimentalFeature?
 
@@ -117,7 +119,6 @@ public class Node: NodeChoiceConvertible {
   /// Construct the specification for a layout syntax node.
   init(
     kind: SyntaxNodeKind,
-    base: SyntaxNodeKind,
     experimentalFeature: ExperimentalFeature? = nil,
     nameForDiagnostics: String?,
     documentation: String? = nil,
@@ -125,11 +126,10 @@ public class Node: NodeChoiceConvertible {
     traits: [String] = [],
     children: [Child] = []
   ) {
-    precondition(base != .syntaxCollection)
-    precondition(base.isBase, "unknown base kind '\(base)' for node '\(kind)'")
+    precondition(kind.base != .syntaxCollection)
+    precondition(kind.base.isBase, "unknown base kind '\(kind.base)' for node '\(kind)'")
 
     self.kind = kind
-    self.base = base
     self.experimentalFeature = experimentalFeature
     self.nameForDiagnostics = nameForDiagnostics
     self.documentation = SwiftSyntax.Trivia.docCommentTrivia(from: documentation)
@@ -274,7 +274,6 @@ public class Node: NodeChoiceConvertible {
   /// `base` must be `.syntaxCollection`.
   init(
     kind: SyntaxNodeKind,
-    base: SyntaxNodeKind,
     experimentalFeature: ExperimentalFeature? = nil,
     nameForDiagnostics: String?,
     documentation: String? = nil,
@@ -282,8 +281,7 @@ public class Node: NodeChoiceConvertible {
     elementChoices: [SyntaxNodeKind]
   ) {
     self.kind = kind
-    precondition(base == .syntaxCollection)
-    self.base = base
+    precondition(kind.base == .syntaxCollection)
     self.experimentalFeature = experimentalFeature
     self.nameForDiagnostics = nameForDiagnostics
     self.documentation = SwiftSyntax.Trivia.docCommentTrivia(from: documentation)
diff --git a/CodeGeneration/Sources/SyntaxSupport/PatternNodes.swift b/CodeGeneration/Sources/SyntaxSupport/PatternNodes.swift
index 83d45dd71ec..c8868aa1ab6 100644
--- a/CodeGeneration/Sources/SyntaxSupport/PatternNodes.swift
+++ b/CodeGeneration/Sources/SyntaxSupport/PatternNodes.swift
@@ -13,7 +13,6 @@
 public let PATTERN_NODES: [Node] = [
   Node(
     kind: .expressionPattern,
-    base: .pattern,
     nameForDiagnostics: "pattern",
     documentation: """
       A pattern that contains an ``ExprSyntaxProtocol``.
@@ -40,7 +39,6 @@ public let PATTERN_NODES: [Node] = [
 
   Node(
     kind: .identifierPattern,
-    base: .pattern,
     nameForDiagnostics: "pattern",
     documentation: """
       A pattern that contains a ``TokenSyntax``.
@@ -72,7 +70,6 @@ public let PATTERN_NODES: [Node] = [
 
   Node(
     kind: .isTypePattern,
-    base: .pattern,
     nameForDiagnostics: "'is' pattern",
     children: [
       Child(
@@ -88,7 +85,6 @@ public let PATTERN_NODES: [Node] = [
 
   Node(
     kind: .tuplePatternElementList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     documentation: """
       A list of ``TuplePatternElementSyntax``.
@@ -98,7 +94,6 @@ public let PATTERN_NODES: [Node] = [
 
   Node(
     kind: .tuplePatternElement,
-    base: .syntax,
     nameForDiagnostics: nil,
     documentation: """
       An element that represents a single tuple value in ``TuplePatternElementListSyntax``.
@@ -138,7 +133,6 @@ public let PATTERN_NODES: [Node] = [
 
   Node(
     kind: .tuplePattern,
-    base: .pattern,
     nameForDiagnostics: "tuple pattern",
     documentation: """
       A pattern that contains a list of other pattern.
@@ -175,7 +169,6 @@ public let PATTERN_NODES: [Node] = [
 
   Node(
     kind: .typeAnnotation,
-    base: .syntax,
     nameForDiagnostics: "type annotation",
     children: [
       Child(
@@ -192,7 +185,6 @@ public let PATTERN_NODES: [Node] = [
 
   Node(
     kind: .valueBindingPattern,
-    base: .pattern,
     nameForDiagnostics: "value binding pattern",
     children: [
       Child(
@@ -214,7 +206,6 @@ public let PATTERN_NODES: [Node] = [
 
   Node(
     kind: .wildcardPattern,
-    base: .pattern,
     nameForDiagnostics: "wildcard pattern",
     documentation: """
       A pattern that represent a wildcard.
diff --git a/CodeGeneration/Sources/SyntaxSupport/RawSyntaxNodeKind.swift b/CodeGeneration/Sources/SyntaxSupport/RawSyntaxNodeKind.swift
index ded2446914e..39a4e8f9f0b 100644
--- a/CodeGeneration/Sources/SyntaxSupport/RawSyntaxNodeKind.swift
+++ b/CodeGeneration/Sources/SyntaxSupport/RawSyntaxNodeKind.swift
@@ -20,6 +20,10 @@ public struct RawSyntaxNodeKind: TypeConvertible {
     self.syntaxNodeKind.isBase
   }
 
+  public var base: RawSyntaxNodeKind {
+    Self(syntaxNodeKind: self.syntaxNodeKind.base)
+  }
+
   public var syntaxType: TypeSyntax {
     "Raw\(self.syntaxNodeKind.syntaxType)"
   }
diff --git a/CodeGeneration/Sources/SyntaxSupport/StmtNodes.swift b/CodeGeneration/Sources/SyntaxSupport/StmtNodes.swift
index 8d641dc5218..47c474a21cb 100644
--- a/CodeGeneration/Sources/SyntaxSupport/StmtNodes.swift
+++ b/CodeGeneration/Sources/SyntaxSupport/StmtNodes.swift
@@ -13,7 +13,6 @@
 public let STMT_NODES: [Node] = [
   Node(
     kind: .availabilityCondition,
-    base: .syntax,
     nameForDiagnostics: "availability condition",
     children: [
       Child(
@@ -38,7 +37,6 @@ public let STMT_NODES: [Node] = [
 
   Node(
     kind: .breakStmt,
-    base: .stmt,
     nameForDiagnostics: "'break' statement",
     children: [
       Child(
@@ -56,21 +54,18 @@ public let STMT_NODES: [Node] = [
 
   Node(
     kind: .switchCaseItemList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.switchCaseItem]
   ),
 
   Node(
     kind: .catchClauseList,
-    base: .syntaxCollection,
     nameForDiagnostics: "'catch' clause",
     elementChoices: [.catchClause]
   ),
 
   Node(
     kind: .catchClause,
-    base: .syntax,
     nameForDiagnostics: "'catch' clause",
     parserFunction: "parseCatchClause",
     traits: ["WithCodeBlock"],
@@ -92,14 +87,12 @@ public let STMT_NODES: [Node] = [
 
   Node(
     kind: .catchItemList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.catchItem]
   ),
 
   Node(
     kind: .catchItem,
-    base: .syntax,
     nameForDiagnostics: nil,
     traits: [
       "WithTrailingComma"
@@ -125,14 +118,12 @@ public let STMT_NODES: [Node] = [
 
   Node(
     kind: .conditionElementList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.conditionElement]
   ),
 
   Node(
     kind: .conditionElement,
-    base: .syntax,
     nameForDiagnostics: nil,
     traits: [
       "WithTrailingComma"
@@ -169,7 +160,6 @@ public let STMT_NODES: [Node] = [
 
   Node(
     kind: .continueStmt,
-    base: .stmt,
     nameForDiagnostics: "'continue' statement",
     children: [
       Child(
@@ -187,7 +177,6 @@ public let STMT_NODES: [Node] = [
 
   Node(
     kind: .deferStmt,
-    base: .stmt,
     nameForDiagnostics: "'defer' statement",
     traits: [
       "WithCodeBlock"
@@ -206,7 +195,6 @@ public let STMT_NODES: [Node] = [
 
   Node(
     kind: .doStmt,
-    base: .stmt,
     nameForDiagnostics: "'do' statement",
     traits: [
       "WithCodeBlock"
@@ -236,7 +224,6 @@ public let STMT_NODES: [Node] = [
 
   Node(
     kind: .expressionStmt,
-    base: .stmt,
     nameForDiagnostics: "expression",
     children: [
       Child(
@@ -248,7 +235,6 @@ public let STMT_NODES: [Node] = [
 
   Node(
     kind: .fallThroughStmt,
-    base: .stmt,
     nameForDiagnostics: "'fallthrough' statement",
     children: [
       Child(
@@ -260,7 +246,6 @@ public let STMT_NODES: [Node] = [
 
   Node(
     kind: .forStmt,
-    base: .stmt,
     nameForDiagnostics: "'for' statement",
     traits: [
       "WithCodeBlock"
@@ -318,7 +303,6 @@ public let STMT_NODES: [Node] = [
 
   Node(
     kind: .discardStmt,
-    base: .stmt,
     nameForDiagnostics: "'discard' statement",
     children: [
       Child(
@@ -334,7 +318,6 @@ public let STMT_NODES: [Node] = [
 
   Node(
     kind: .guardStmt,
-    base: .stmt,
     nameForDiagnostics: "'guard' statement",
     traits: [
       "WithCodeBlock"
@@ -363,7 +346,6 @@ public let STMT_NODES: [Node] = [
 
   Node(
     kind: .labeledStmt,
-    base: .stmt,
     nameForDiagnostics: "labeled statement",
     children: [
       Child(
@@ -386,7 +368,6 @@ public let STMT_NODES: [Node] = [
 
   Node(
     kind: .matchingPatternCondition,
-    base: .syntax,
     nameForDiagnostics: "pattern matching",
     children: [
       Child(
@@ -411,7 +392,6 @@ public let STMT_NODES: [Node] = [
 
   Node(
     kind: .optionalBindingCondition,
-    base: .syntax,
     nameForDiagnostics: "optional binding",
     children: [
       Child(
@@ -441,7 +421,6 @@ public let STMT_NODES: [Node] = [
 
   Node(
     kind: .repeatStmt,
-    base: .stmt,
     nameForDiagnostics: "'repeat' statement",
     traits: [
       "WithCodeBlock"
@@ -470,7 +449,6 @@ public let STMT_NODES: [Node] = [
 
   Node(
     kind: .returnStmt,
-    base: .stmt,
     nameForDiagnostics: "'return' statement",
     children: [
       Child(
@@ -487,7 +465,6 @@ public let STMT_NODES: [Node] = [
 
   Node(
     kind: .throwStmt,
-    base: .stmt,
     nameForDiagnostics: "'throw' statement",
     children: [
       Child(
@@ -503,7 +480,6 @@ public let STMT_NODES: [Node] = [
 
   Node(
     kind: .whereClause,
-    base: .syntax,
     nameForDiagnostics: "'where' clause",
     children: [
       Child(
@@ -520,7 +496,6 @@ public let STMT_NODES: [Node] = [
 
   Node(
     kind: .whileStmt,
-    base: .stmt,
     nameForDiagnostics: "'while' statement",
     traits: [
       "WithCodeBlock"
@@ -543,7 +518,6 @@ public let STMT_NODES: [Node] = [
 
   Node(
     kind: .yieldedExpressionsClause,
-    base: .syntax,
     nameForDiagnostics: nil,
     children: [
       Child(
@@ -564,7 +538,6 @@ public let STMT_NODES: [Node] = [
 
   Node(
     kind: .yieldStmt,
-    base: .stmt,
     nameForDiagnostics: "'yield' statement",
     children: [
       Child(
@@ -592,7 +565,6 @@ public let STMT_NODES: [Node] = [
 
   Node(
     kind: .thenStmt,
-    base: .stmt,
     experimentalFeature: .thenStatements,
     nameForDiagnostics: "'then' statement",
     documentation: """
diff --git a/CodeGeneration/Sources/SyntaxSupport/SyntaxNodeKind.swift b/CodeGeneration/Sources/SyntaxSupport/SyntaxNodeKind.swift
index aca5c52aa86..057fef48458 100644
--- a/CodeGeneration/Sources/SyntaxSupport/SyntaxNodeKind.swift
+++ b/CodeGeneration/Sources/SyntaxSupport/SyntaxNodeKind.swift
@@ -336,6 +336,80 @@ public enum SyntaxNodeKind: String, CaseIterable, IdentifierConvertible, TypeCon
     }
   }
 
+  public var base: Self {
+    switch self {
+    case .accessorDecl, .actorDecl, .associatedTypeDecl, .classDecl, .deinitializerDecl, .editorPlaceholderDecl,
+      .enumCaseDecl, .enumDecl, .extensionDecl, .functionDecl, .ifConfigDecl, .importDecl, .initializerDecl, .macroDecl,
+      .macroExpansionDecl, .missingDecl, .operatorDecl, .poundSourceLocation, .precedenceGroupDecl, .protocolDecl,
+      .structDecl, .subscriptDecl, .typeAliasDecl, .variableDecl:
+      return .decl
+    case ._canImportExpr, ._canImportVersionInfo, .arrayExpr, .arrowExpr, .asExpr, .assignmentExpr, .awaitExpr,
+      .binaryOperatorExpr, .booleanLiteralExpr, .borrowExpr, .closureExpr, .consumeExpr, .copyExpr, .declReferenceExpr,
+      .dictionaryExpr, .discardAssignmentExpr, .doExpr, .editorPlaceholderExpr, .floatLiteralExpr, .forceUnwrapExpr,
+      .functionCallExpr, .genericSpecializationExpr, .ifExpr, .infixOperatorExpr, .inOutExpr, .integerLiteralExpr,
+      .isExpr, .keyPathExpr, .macroExpansionExpr, .memberAccessExpr, .missingExpr, .nilLiteralExpr,
+      .optionalChainingExpr, .packElementExpr, .packExpansionExpr, .patternExpr, .postfixIfConfigExpr,
+      .postfixOperatorExpr, .prefixOperatorExpr, .regexLiteralExpr, .sequenceExpr, .simpleStringLiteralExpr,
+      .stringLiteralExpr, .subscriptCallExpr, .superExpr, .switchExpr, .ternaryExpr, .tryExpr, .tupleExpr, .typeExpr,
+      .unresolvedAsExpr, .unresolvedIsExpr, .unresolvedTernaryExpr:
+      return .expr
+    case .expressionPattern, .identifierPattern, .isTypePattern, .missingPattern, .tuplePattern, .valueBindingPattern,
+      .wildcardPattern:
+      return .pattern
+    case .breakStmt, .continueStmt, .deferStmt, .discardStmt, .doStmt, .expressionStmt, .fallThroughStmt, .forStmt,
+      .guardStmt, .labeledStmt, .missingStmt, .repeatStmt, .returnStmt, .thenStmt, .throwStmt, .whileStmt, .yieldStmt:
+      return .stmt
+    case .arrayType, .attributedType, .classRestrictionType, .compositionType, .dictionaryType, .functionType,
+      .identifierType, .implicitlyUnwrappedOptionalType, .memberType, .metatypeType, .missingType,
+      .namedOpaqueReturnType, .optionalType, .packElementType, .packExpansionType, .someOrAnyType, .suppressedType,
+      .tupleType:
+      return .type
+    case .accessorDeclList, .arrayElementList, .attributeList, .availabilityArgumentList, .catchClauseList,
+      .catchItemList, .closureCaptureList, .closureParameterList, .closureShorthandParameterList, .codeBlockItemList,
+      .compositionTypeElementList, .conditionElementList, .declModifierList, .declNameArgumentList, .designatedTypeList,
+      .dictionaryElementList, .differentiabilityArgumentList, .documentationAttributeArgumentList,
+      .effectsAttributeArgumentList, .enumCaseElementList, .enumCaseParameterList, .exprList, .functionParameterList,
+      .genericArgumentList, .genericParameterList, .genericRequirementList, .ifConfigClauseList,
+      .importPathComponentList, .inheritedTypeList, .keyPathComponentList, .labeledExprList,
+      .lifetimeSpecifierArgumentList, .memberBlockItemList, .multipleTrailingClosureElementList, .objCSelectorPieceList,
+      .patternBindingList, .platformVersionItemList, .precedenceGroupAttributeList, .precedenceGroupNameList,
+      .primaryAssociatedTypeList, .simpleStringLiteralSegmentList, .specializeAttributeArgumentList,
+      .stringLiteralSegmentList, .switchCaseItemList, .switchCaseList, .tuplePatternElementList, .tupleTypeElementList,
+      .typeSpecifierList, .unexpectedNodes, .versionComponentList, .yieldedExpressionList:
+      return .syntaxCollection
+    case .accessorBlock, .accessorEffectSpecifiers, .accessorParameters, .arrayElement, .attribute,
+      .availabilityArgument, .availabilityCondition, .availabilityLabeledArgument, .backDeployedAttributeArguments,
+      .catchClause, .catchItem, .closureCapture, .closureCaptureClause, .closureCaptureSpecifier, .closureParameter,
+      .closureParameterClause, .closureShorthandParameter, .closureSignature, .codeBlock, .codeBlockItem,
+      .compositionTypeElement, .conditionElement, .conformanceRequirement, .conventionAttributeArguments,
+      .conventionWitnessMethodAttributeArguments, .decl, .declModifier, .declModifierDetail, .declNameArgument,
+      .declNameArguments, .deinitializerEffectSpecifiers, .derivativeAttributeArguments, .designatedType,
+      .dictionaryElement, .differentiabilityArgument, .differentiabilityArguments,
+      .differentiabilityWithRespectToArgument, .differentiableAttributeArguments, .documentationAttributeArgument,
+      .dynamicReplacementAttributeArguments, .enumCaseElement, .enumCaseParameter, .enumCaseParameterClause,
+      .exposeAttributeArguments, .expr, .expressionSegment, .functionEffectSpecifiers, .functionParameter,
+      .functionParameterClause, .functionSignature, .genericArgument, .genericArgumentClause, .genericParameter,
+      .genericParameterClause, .genericRequirement, .genericWhereClause, .ifConfigClause, .implementsAttributeArguments,
+      .importPathComponent, .inheritanceClause, .inheritedType, .initializerClause, .keyPathComponent,
+      .keyPathOptionalComponent, .keyPathPropertyComponent, .keyPathSubscriptComponent, .labeledExpr,
+      .labeledSpecializeArgument, .layoutRequirement, .lifetimeSpecifierArgument, .lifetimeTypeSpecifier,
+      .matchingPatternCondition, .memberBlock, .memberBlockItem, .missing, .multipleTrailingClosureElement,
+      .objCSelectorPiece, .opaqueReturnTypeOfAttributeArguments, .operatorPrecedenceAndTypes, .optionalBindingCondition,
+      .originallyDefinedInAttributeArguments, .pattern, .patternBinding, .platformVersion, .platformVersionItem,
+      .poundSourceLocationArguments, .precedenceGroupAssignment, .precedenceGroupAssociativity, .precedenceGroupName,
+      .precedenceGroupRelation, .primaryAssociatedType, .primaryAssociatedTypeClause, .returnClause,
+      .sameTypeRequirement, .simpleTypeSpecifier, .sourceFile, .specializeAvailabilityArgument,
+      .specializeTargetFunctionArgument, .stmt, .stringSegment, .switchCase, .switchCaseItem, .switchCaseLabel,
+      .switchDefaultLabel, .throwsClause, .tuplePatternElement, .tupleTypeElement, .type, .typeAnnotation,
+      .typeEffectSpecifiers, .typeInitializerClause, .typeSpecifier, .lifetimeSpecifierArguments,
+      .unavailableFromAsyncAttributeArguments, .underscorePrivateAttributeArguments, .versionComponent, .versionTuple,
+      .whereClause, .yieldedExpression, .yieldedExpressionsClause:
+      return .syntax
+    case .syntax, .syntaxCollection, .token:
+      return .syntax
+    }
+  }
+
   public var identifier: TokenSyntax {
     return .identifier(rawValue)
   }
diff --git a/CodeGeneration/Sources/SyntaxSupport/TypeNodes.swift b/CodeGeneration/Sources/SyntaxSupport/TypeNodes.swift
index 527843d4e90..3960397fc6b 100644
--- a/CodeGeneration/Sources/SyntaxSupport/TypeNodes.swift
+++ b/CodeGeneration/Sources/SyntaxSupport/TypeNodes.swift
@@ -13,7 +13,6 @@
 public let TYPE_NODES: [Node] = [
   Node(
     kind: .arrayType,
-    base: .type,
     nameForDiagnostics: "array type",
     children: [
       Child(
@@ -36,7 +35,6 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .attributedType,
-    base: .type,
     nameForDiagnostics: "type",
     traits: [
       "WithAttributes"
@@ -63,7 +61,6 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .classRestrictionType,
-    base: .type,
     nameForDiagnostics: nil,
     children: [
       Child(
@@ -75,14 +72,12 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .compositionTypeElementList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.compositionTypeElement]
   ),
 
   Node(
     kind: .compositionTypeElement,
-    base: .syntax,
     nameForDiagnostics: nil,
     children: [
       Child(
@@ -99,7 +94,6 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .compositionType,
-    base: .type,
     nameForDiagnostics: "type composition",
     children: [
       Child(
@@ -111,7 +105,6 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .someOrAnyType,
-    base: .type,
     nameForDiagnostics: "type",
     children: [
       Child(
@@ -128,7 +121,6 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .dictionaryType,
-    base: .type,
     nameForDiagnostics: "dictionary type",
     children: [
       Child(
@@ -162,7 +154,6 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .functionType,
-    base: .type,
     nameForDiagnostics: "function type",
     traits: [
       "Parenthesized"
@@ -200,7 +191,6 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .genericArgumentClause,
-    base: .syntax,
     nameForDiagnostics: "generic argument clause",
     children: [
       Child(
@@ -222,14 +212,12 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .genericArgumentList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.genericArgument]
   ),
 
   Node(
     kind: .genericArgument,
-    base: .syntax,
     nameForDiagnostics: "generic argument",
     traits: [
       "WithTrailingComma"
@@ -250,7 +238,6 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .implicitlyUnwrappedOptionalType,
-    base: .type,
     nameForDiagnostics: "implicitly unwrapped optional type",
     children: [
       Child(
@@ -266,7 +253,6 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .memberType,
-    base: .type,
     nameForDiagnostics: "member type",
     children: [
       Child(
@@ -293,7 +279,6 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .metatypeType,
-    base: .type,
     nameForDiagnostics: "metatype",
     children: [
       Child(
@@ -315,7 +300,6 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .namedOpaqueReturnType,
-    base: .type,
     nameForDiagnostics: "named opaque return type",
     children: [
       Child(
@@ -334,7 +318,6 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .optionalType,
-    base: .type,
     nameForDiagnostics: "optional type",
     children: [
       Child(
@@ -350,7 +333,6 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .suppressedType,
-    base: .type,
     nameForDiagnostics: "suppressed type conformance",
     children: [
       Child(
@@ -367,7 +349,6 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .packExpansionType,
-    base: .type,
     nameForDiagnostics: "variadic expansion",
     children: [
       Child(
@@ -384,7 +365,6 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .packElementType,
-    base: .type,
     nameForDiagnostics: "pack element",
     children: [
       Child(
@@ -401,7 +381,6 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .identifierType,
-    base: .type,
     nameForDiagnostics: "type",
     children: [
       Child(
@@ -423,14 +402,12 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .tupleTypeElementList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.tupleTypeElement]
   ),
 
   Node(
     kind: .tupleTypeElement,
-    base: .syntax,
     nameForDiagnostics: nil,
     traits: [
       "WithTrailingComma"
@@ -479,7 +456,6 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .tupleType,
-    base: .type,
     nameForDiagnostics: "tuple type",
     traits: [
       "Parenthesized"
@@ -502,7 +478,6 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .lifetimeSpecifierArgument,
-    base: .syntax,
     experimentalFeature: .nonescapableTypes,
     nameForDiagnostics: nil,
     documentation: """
@@ -536,7 +511,6 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .lifetimeSpecifierArgumentList,
-    base: .syntaxCollection,
     experimentalFeature: .nonescapableTypes,
     nameForDiagnostics: nil,
     elementChoices: [.lifetimeSpecifierArgument]
@@ -544,7 +518,6 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .lifetimeTypeSpecifier,
-    base: .syntax,
     experimentalFeature: .nonescapableTypes,
     nameForDiagnostics: "lifetime specifier",
     documentation: "A specifier that specifies function parameter on whose lifetime a type depends",
@@ -577,7 +550,6 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .simpleTypeSpecifier,
-    base: .syntax,
     nameForDiagnostics: "type specifier",
     documentation: "A specifier that can be attached to a type to eg. mark a parameter as `inout` or `consuming`",
     children: [
@@ -600,7 +572,6 @@ public let TYPE_NODES: [Node] = [
 
   Node(
     kind: .typeSpecifierList,
-    base: .syntaxCollection,
     nameForDiagnostics: nil,
     elementChoices: [.simpleTypeSpecifier, .lifetimeTypeSpecifier]
   ),