Move syntax tree lint/format rules into @_spi(Rules).

Author: allevato

Sources/SwiftFormat/Rules/AllPublicDeclarationsHaveDocumentation.swift

@@ -15,6 +15,7 @@ import SwiftSyntax
 /// All public or open declarations must have a top-level documentation comment.
 ///
 /// Lint: If a public declaration is missing a documentation comment, a lint error is raised.
+@_spi(Rules)
 public final class AllPublicDeclarationsHaveDocumentation: SyntaxLintRule {
 
   /// Identifies this rule as being opt-in. While docs on most public declarations are beneficial,
@@ -86,6 +87,7 @@ public final class AllPublicDeclarationsHaveDocumentation: SyntaxLintRule {
 }
 
 extension Finding.Message {
+  @_spi(Rules)
   public static func declRequiresComment(_ name: String) -> Finding.Message {
     "add a documentation comment for '\(name)'"
   }

Sources/SwiftFormat/Rules/AlwaysUseLowerCamelCase.swift

@@ -20,6 +20,7 @@ import SwiftSyntax
 ///
 /// Lint: If an identifier contains underscores or begins with a capital letter, a lint error is
 ///       raised.
+@_spi(Rules)
 public final class AlwaysUseLowerCamelCase: SyntaxLintRule {
   /// Stores function decls that are test cases.
   private var testCaseFuncs = Set<FunctionDeclSyntax>()
@@ -213,6 +214,7 @@ extension ReturnClauseSyntax {
 }
 
 extension Finding.Message {
+  @_spi(Rules)
   public static func nameMustBeLowerCamelCase(
     _ name: String, description: String
   ) -> Finding.Message {

Sources/SwiftFormat/Rules/AmbiguousTrailingClosureOverload.swift

@@ -16,6 +16,7 @@ import SwiftSyntax
 ///
 /// Lint: If two overloaded functions with one closure parameter appear in the same scope, a lint
 ///       error is raised.
+@_spi(Rules)
 public final class AmbiguousTrailingClosureOverload: SyntaxLintRule {
 
   private func diagnoseBadOverloads(_ overloads: [String: [FunctionDeclSyntax]]) {
@@ -72,10 +73,12 @@ public final class AmbiguousTrailingClosureOverload: SyntaxLintRule {
 }
 
 extension Finding.Message {
+  @_spi(Rules)
   public static func ambiguousTrailingClosureOverload(_ decl: String) -> Finding.Message {
     "rename '\(decl)' so it is no longer ambiguous when called with a trailing closure"
   }
 
+  @_spi(Rules)
   public static func otherAmbiguousOverloadHere(_ decl: String) -> Finding.Message {
     "ambiguous overload '\(decl)' is here"
   }

Sources/SwiftFormat/Rules/BeginDocumentationCommentWithOneLineSummary.swift

@@ -16,6 +16,7 @@ import SwiftSyntax
 /// All documentation comments must begin with a one-line summary of the declaration.
 ///
 /// Lint: If a comment does not begin with a single-line summary, a lint error is raised.
+@_spi(Rules)
 public final class BeginDocumentationCommentWithOneLineSummary: SyntaxLintRule {
 
   /// Unit tests can testably import this module and set this to true in order to force the rule
@@ -194,12 +195,14 @@ public final class BeginDocumentationCommentWithOneLineSummary: SyntaxLintRule {
 }
 
 extension Finding.Message {
+  @_spi(Rules)
   public static func terminateSentenceWithPeriod<Sentence: StringProtocol>(_ text: Sentence)
     -> Finding.Message
   {
     "terminate this sentence with a period: \"\(text)\""
   }
 
+  @_spi(Rules)
   public static func addBlankLineAfterFirstSentence<Sentence: StringProtocol>(_ text: Sentence)
     -> Finding.Message
   {

Sources/SwiftFormat/Rules/DoNotUseSemicolons.swift

@@ -17,6 +17,7 @@ import SwiftSyntax
 /// Lint: If a semicolon appears anywhere, a lint error is raised.
 ///
 /// Format: All semicolons will be replaced with line breaks.
+@_spi(Rules)
 public final class DoNotUseSemicolons: SyntaxFormatRule {
 
   /// Creates a new version of the given node which doesn't contain any semicolons. The node's
@@ -102,8 +103,10 @@ public final class DoNotUseSemicolons: SyntaxFormatRule {
 }
 
 extension Finding.Message {
+  @_spi(Rules)
   public static let removeSemicolon: Finding.Message = "remove ';'"
 
+  @_spi(Rules)
   public static let removeSemicolonAndMove: Finding.Message =
     "remove ';' and move the next statement to a new line"
 }

Sources/SwiftFormat/Rules/DontRepeatTypeInStaticProperties.swift

@@ -19,6 +19,7 @@ import SwiftSyntax
 /// `public class var redColor: UIColor` would trigger this rule.
 ///
 /// Lint: Static properties of a type that return that type will yield a lint error.
+@_spi(Rules)
 public final class DontRepeatTypeInStaticProperties: SyntaxLintRule {
 
   public override func visit(_ node: ClassDeclSyntax) -> SyntaxVisitorContinueKind {
@@ -101,6 +102,7 @@ public final class DontRepeatTypeInStaticProperties: SyntaxLintRule {
 }
 
 extension Finding.Message {
+  @_spi(Rules)
   public static func removeTypeFromName(name: String, type: Substring) -> Finding.Message {
     "remove the suffix '\(type)' from the name of the variable '\(name)'"
   }

Sources/SwiftFormat/Rules/FileScopedDeclarationPrivacy.swift

@@ -20,6 +20,7 @@ import SwiftSyntax
 ///
 /// Format: File-scoped declarations that have formal access opposite to the desired access level in
 ///         the formatter's configuration will have their access level changed.
+@_spi(Rules)
 public final class FileScopedDeclarationPrivacy: SyntaxFormatRule {
   public override func visit(_ node: SourceFileSyntax) -> SourceFileSyntax {
     let newStatements = rewrittenCodeBlockItems(node.statements)
@@ -169,9 +170,11 @@ public final class FileScopedDeclarationPrivacy: SyntaxFormatRule {
 }
 
 extension Finding.Message {
+  @_spi(Rules)
   public static let replacePrivateWithFileprivate: Finding.Message =
     "replace 'private' with 'fileprivate' on file-scoped declarations"
 
+  @_spi(Rules)
   public static let replaceFileprivateWithPrivate: Finding.Message =
     "replace 'fileprivate' with 'private' on file-scoped declarations"
 }

Sources/SwiftFormat/Rules/FullyIndirectEnum.swift

@@ -19,6 +19,7 @@ import SwiftSyntax
 ///
 /// Format: Enums where all cases are `indirect` will be rewritten such that the enum is marked
 ///         `indirect`, and each case is not.
+@_spi(Rules)
 public final class FullyIndirectEnum: SyntaxFormatRule {
 
   public override func visit(_ node: EnumDeclSyntax) -> DeclSyntax {
@@ -109,6 +110,7 @@ public final class FullyIndirectEnum: SyntaxFormatRule {
 }
 
 extension Finding.Message {
+  @_spi(Rules)
   public static func moveIndirectKeywordToEnumDecl(name: String) -> Finding.Message {
     "move 'indirect' before the enum declaration '\(name)' when all cases are indirect"
   }

Sources/SwiftFormat/Rules/GroupNumericLiterals.swift

@@ -24,6 +24,7 @@ import SwiftSyntax
 /// TODO: Minimum numeric literal length bounds and numeric groupings have been selected arbitrarily;
 /// these could be reevaluated.
 /// TODO: Handle floating point literals.
+@_spi(Rules)
 public final class GroupNumericLiterals: SyntaxFormatRule {
   public override func visit(_ node: IntegerLiteralExprSyntax) -> ExprSyntax {
     var originalDigits = node.literal.text
@@ -82,6 +83,7 @@ public final class GroupNumericLiterals: SyntaxFormatRule {
 }
 
 extension Finding.Message {
+  @_spi(Rules)
   public static func groupNumericLiteral(every stride: Int) -> Finding.Message {
     let ending = stride == 3 ? "rd" : "th"
     return "group numeric literal using '_' every \(stride)\(ending) number"

Sources/SwiftFormat/Rules/IdentifiersMustBeASCII.swift

@@ -15,6 +15,7 @@ import SwiftSyntax
 /// All identifiers must be ASCII.
 ///
 /// Lint: If an identifier contains non-ASCII characters, a lint error is raised.
+@_spi(Rules)
 public final class IdentifiersMustBeASCII: SyntaxLintRule {
 
   public override func visit(_ node: IdentifierPatternSyntax) -> SyntaxVisitorContinueKind {
@@ -30,6 +31,7 @@ public final class IdentifiersMustBeASCII: SyntaxLintRule {
 }
 
 extension Finding.Message {
+  @_spi(Rules)
   public static func nonASCIICharsNotAllowed(
     _ invalidCharacters: [String], _ identifierName: String
   ) -> Finding.Message {