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[Parser] Attributes on MacroExpansionDeclSyntax #1650

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Merged
merged 1 commit into from
May 15, 2023
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[Parser] Attributes on MacroExpansionDeclSyntax #1650

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12 changes: 12 additions & 0 deletions CodeGeneration/Sources/SyntaxSupport/DeclNodes.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -1278,6 +1278,18 @@ public let DECL_NODES: [Node] = [
"FreestandingMacroExpansion"
],
children: [
Child(
name: "Attributes",
kind: .collection(kind: "AttributeList", collectionElementName: "Attribute"),
nameForDiagnostics: "attributes",
isOptional: true
),
Child(
name: "Modifiers",
kind: .collection(kind: "ModifierList", collectionElementName: "Modifier"),
nameForDiagnostics: "modifiers",
isOptional: true
),
Child(
name: "PoundToken",
kind: .token(choices: [.token(tokenKind: "PoundToken")]),
Expand Down
67 changes: 54 additions & 13 deletions Sources/SwiftParser/Declarations.swift
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Expand Up @@ -29,18 +29,25 @@ extension DeclarationModifier {
}

extension TokenConsumer {
mutating func atStartOfFreestandingMacroExpansion() -> Bool {
if !self.at(.pound) {
return false
}
if self.peek().rawTokenKind != .identifier && !self.peek().isLexerClassifiedKeyword {
return false
}
if self.currentToken.trailingTriviaByteLength != 0 || self.peek().leadingTriviaByteLength != 0 {
return false
}
return true
}

mutating func atStartOfDeclaration(
isAtTopLevel: Bool = false,
allowInitDecl: Bool = true,
allowRecovery: Bool = false
) -> Bool {
if self.at(anyIn: PoundDeclarationStart.self) != nil {
// Don't treat freestanding macro expansions as declarations. They'll be
// parsed as expressions.
if self.at(.pound) {
return false
}

return true
}

Expand All @@ -53,12 +60,14 @@ extension TokenConsumer {
_ = subparser.consumeAttributeList()
}

var hasModifier = false
if subparser.currentToken.isLexerClassifiedKeyword || subparser.currentToken.rawTokenKind == .identifier {
var modifierProgress = LoopProgressCondition()
while let (modifierKind, handle) = subparser.at(anyIn: DeclarationModifier.self),
modifierKind != .class,
modifierProgress.evaluate(subparser.currentToken)
{
hasModifier = true
subparser.eat(handle)
if modifierKind != .open && subparser.at(.leftParen) && modifierKind.canHaveParenthesizedArgument {
// When determining whether we are at a declaration, don't consume anything in parentheses after 'open'
Expand Down Expand Up @@ -113,6 +122,16 @@ extension TokenConsumer {
case .macroKeyword:
// macro Foo ...
return subparser.peek().rawTokenKind == .identifier
case .pound:
// Force parsing '#<identifier>' after attributes as a macro expansion decl.
if hasAttribute || hasModifier {
return true
}

// Otherwise, parse it as a expression.
// FIXME: C++ parser returns true if this is a top-level non-"script" files.
// But we don't have "is library" flag.
return false
case .some(_):
// All other decl start keywords unconditonally start a decl.
return true
Expand Down Expand Up @@ -203,10 +222,6 @@ extension Parser {
return .decls(RawMemberDeclListSyntax(elements: elements, arena: parser.arena))
}
return RawDeclSyntax(directive)
case (.pound, _)?:
// FIXME: If we can have attributes for macro expansions, handle this
// via DeclarationStart.
return RawDeclSyntax(self.parseMacroExpansionDeclaration())
case nil:
break
}
Expand Down Expand Up @@ -258,6 +273,8 @@ extension Parser {
return RawDeclSyntax(self.parseNominalTypeDeclaration(for: RawActorDeclSyntax.self, attrs: attrs, introucerHandle: handle))
case (.macroKeyword, let handle)?:
return RawDeclSyntax(self.parseMacroDeclaration(attrs: attrs, introducerHandle: handle))
case (.pound, let handle)?:
return RawDeclSyntax(self.parseMacroExpansionDeclaration(attrs, handle))
case nil:
if inMemberDeclList {
let isProbablyVarDecl = self.at(.identifier, .wildcard) && self.peek().rawTokenKind.is(.colon, .equal, .comma)
Expand Down Expand Up @@ -2023,9 +2040,30 @@ extension Parser {
/// =======
///
/// macro-expansion-declaration → '#' identifier expr-call-suffix?
mutating func parseMacroExpansionDeclaration() -> RawMacroExpansionDeclSyntax {
let poundKeyword = self.consumeAnyToken()
let (unexpectedBeforeMacro, macro) = self.expectIdentifier()
mutating func parseMacroExpansionDeclaration(
_ attrs: DeclAttributes,
_ handle: RecoveryConsumptionHandle
) -> RawMacroExpansionDeclSyntax {

let (unexpectedBeforePound, poundKeyword) = self.eat(handle)
// Don't allow space between '#' and the macro name.
if poundKeyword.trailingTriviaByteLength != 0 || self.currentToken.leadingTriviaByteLength != 0 {
return RawMacroExpansionDeclSyntax(
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The intent here is that parse # followed by whitespaces as #<missing identifier>, and let the caller do the recovery.

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I think we should still continue macro attribute parsing if the identifier is at the same line as the #. I would expect that to yield better recovery.

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What would you expect as the parsed tree. How do we embed "hasError"?

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For example if you have # elif, we should have unexpectedBeforeMacroName = ' elif' and macroName should be a missing identifier with text elif. That’s also what we do when parsing a. b (where whitespace around the . is not balanced).

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Thanks. Will do.

attributes: attrs.attributes,
modifiers: attrs.modifiers,
unexpectedBeforePound,
poundToken: poundKeyword,
macro: self.missingToken(.identifier),
genericArguments: nil,
leftParen: nil,
argumentList: .init(elements: [], arena: self.arena),
rightParen: nil,
trailingClosure: nil,
additionalTrailingClosures: nil,
arena: self.arena
)
}
let (unexpectedBeforeMacro, macro) = self.expectIdentifier(keywordRecovery: true)

// Parse the optional generic argument list.
let generics: RawGenericArgumentClauseSyntax?
Expand Down Expand Up @@ -2063,6 +2101,9 @@ extension Parser {
}

return RawMacroExpansionDeclSyntax(
attributes: attrs.attributes,
modifiers: attrs.modifiers,
unexpectedBeforePound,
poundToken: poundKeyword,
unexpectedBeforeMacro,
macro: macro,
Expand Down
15 changes: 14 additions & 1 deletion Sources/SwiftParser/Expressions.swift
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Expand Up @@ -1394,8 +1394,21 @@ extension Parser {
pattern: PatternContext,
flavor: ExprFlavor
) -> RawMacroExpansionExprSyntax {
if !atStartOfFreestandingMacroExpansion() {
return RawMacroExpansionExprSyntax(
poundToken: self.consumeAnyToken(),
macro: self.missingToken(.identifier),
genericArguments: nil,
leftParen: nil,
argumentList: .init(elements: [], arena: self.arena),
rightParen: nil,
trailingClosure: nil,
additionalTrailingClosures: nil,
arena: self.arena
)
}
let poundKeyword = self.consumeAnyToken()
let (unexpectedBeforeMacro, macro) = self.expectIdentifier()
let (unexpectedBeforeMacro, macro) = self.expectIdentifier(keywordRecovery: true)
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e.g. #class is invalid but should be recoverable.

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Could you add a test case for #<keyword>?


// Parse the optional generic argument list.
let generics: RawGenericArgumentClauseSyntax?
Expand Down
6 changes: 3 additions & 3 deletions Sources/SwiftParser/TokenSpecSet.swift
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Expand Up @@ -272,6 +272,7 @@ enum DeclarationStart: TokenSpecSet {
case typealiasKeyword
case varKeyword
case inoutKeyword
case pound

init?(lexeme: Lexer.Lexeme) {
switch PrepareForKeywordMatch(lexeme) {
Expand All @@ -295,6 +296,7 @@ enum DeclarationStart: TokenSpecSet {
case TokenSpec(.typealias): self = .typealiasKeyword
case TokenSpec(.var): self = .varKeyword
case TokenSpec(.inout): self = .inoutKeyword
case TokenSpec(.pound): self = .pound
default: return nil
}
}
Expand All @@ -321,6 +323,7 @@ enum DeclarationStart: TokenSpecSet {
case .typealiasKeyword: return .keyword(.typealias)
case .varKeyword: return .keyword(.var)
case .inoutKeyword: return TokenSpec(.inout, recoveryPrecedence: .declKeyword)
case .pound: return TokenSpec(.pound, recoveryPrecedence: .openingPoundIf)
}
}
}
Expand Down Expand Up @@ -396,20 +399,17 @@ enum OperatorLike: TokenSpecSet {

enum PoundDeclarationStart: TokenSpecSet {
case poundIfKeyword
case pound

init?(lexeme: Lexer.Lexeme) {
switch lexeme.rawTokenKind {
case .poundIfKeyword: self = .poundIfKeyword
case .pound: self = .pound
default: return nil
}
}

var spec: TokenSpec {
switch self {
case .poundIfKeyword: return .poundIfKeyword
case .pound: return .pound
}
}
}
Expand Down
4 changes: 4 additions & 0 deletions Sources/SwiftParserDiagnostics/generated/ChildNameForDiagnostics.swift
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Expand Up @@ -236,6 +236,10 @@ private func childNameForDiagnostics(_ keyPath: AnyKeyPath) -> String? {
return "macro definition"
case \MacroDeclSyntax.genericWhereClause:
return "generic where clause"
case \MacroExpansionDeclSyntax.attributes:
return "attributes"
case \MacroExpansionDeclSyntax.modifiers:
return "modifiers"
case \MemberAccessExprSyntax.base:
return "base"
case \MemberAccessExprSyntax.name:
Expand Down
12 changes: 10 additions & 2 deletions Sources/SwiftSyntax/generated/ChildNameForKeyPath.swift
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Expand Up @@ -1995,8 +1995,16 @@ public func childName(_ keyPath: AnyKeyPath) -> String? {
return "genericWhereClause"
case \MacroDeclSyntax.unexpectedAfterGenericWhereClause:
return "unexpectedAfterGenericWhereClause"
case \MacroExpansionDeclSyntax.unexpectedBeforePoundToken:
return "unexpectedBeforePoundToken"
case \MacroExpansionDeclSyntax.unexpectedBeforeAttributes:
return "unexpectedBeforeAttributes"
case \MacroExpansionDeclSyntax.attributes:
return "attributes"
case \MacroExpansionDeclSyntax.unexpectedBetweenAttributesAndModifiers:
return "unexpectedBetweenAttributesAndModifiers"
case \MacroExpansionDeclSyntax.modifiers:
return "modifiers"
case \MacroExpansionDeclSyntax.unexpectedBetweenModifiersAndPoundToken:
return "unexpectedBetweenModifiersAndPoundToken"
case \MacroExpansionDeclSyntax.poundToken:
return "poundToken"
case \MacroExpansionDeclSyntax.unexpectedBetweenPoundTokenAndMacro:
Expand Down
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