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Jan 26, 2023
Merged

Improve diagnostics for effect specifiers #1260

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56 changes: 56 additions & 0 deletions CodeGeneration/Sources/SyntaxSupport/gyb_generated/CommonNodes.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -132,6 +132,62 @@ public let COMMON_NODES: [Node] = [
requiresLeadingNewline: true)
]),

Node(name: "DeclEffectSpecifiers",
nameForDiagnostics: "effect specifiers",
kind: "Syntax",
traits: [
"EffectSpecifiers"
],
children: [
Child(name: "AsyncSpecifier",
kind: "KeywordToken",
isOptional: true,
tokenChoices: [
"Keyword"
],
textChoices: [
"async",
"reasync"
]),
Child(name: "ThrowsSpecifier",
kind: "KeywordToken",
isOptional: true,
tokenChoices: [
"Keyword"
],
textChoices: [
"throws",
"rethrows"
])
]),

Node(name: "TypeEffectSpecifiers",
nameForDiagnostics: "effect specifiers",
kind: "Syntax",
traits: [
"EffectSpecifiers"
],
children: [
Child(name: "AsyncSpecifier",
kind: "KeywordToken",
isOptional: true,
tokenChoices: [
"Keyword"
],
textChoices: [
"async"
]),
Child(name: "ThrowsSpecifier",
kind: "KeywordToken",
isOptional: true,
tokenChoices: [
"Keyword"
],
textChoices: [
"throws"
])
]),

Node(name: "UnexpectedNodes",
nameForDiagnostics: nil,
description: "A collection of syntax nodes that occurred in the source code butcould not be used to form a valid syntax tree.",
Expand Down
45 changes: 6 additions & 39 deletions CodeGeneration/Sources/SyntaxSupport/gyb_generated/DeclNodes.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -152,26 +152,9 @@ public let DECL_NODES: [Node] = [
children: [
Child(name: "Input",
kind: "ParameterClause"),
Child(name: "AsyncOrReasyncKeyword",
kind: "KeywordToken",
isOptional: true,
tokenChoices: [
"Keyword"
],
textChoices: [
"async",
"reasync"
]),
Child(name: "ThrowsOrRethrowsKeyword",
kind: "KeywordToken",
isOptional: true,
tokenChoices: [
"Keyword"
],
textChoices: [
"throws",
"rethrows"
]),
Child(name: "EffectSpecifiers",
kind: "DeclEffectSpecifiers",
isOptional: true),
Child(name: "Output",
kind: "ReturnClause",
isOptional: true)
Expand Down Expand Up @@ -1090,25 +1073,9 @@ public let DECL_NODES: [Node] = [
Child(name: "Parameter",
kind: "AccessorParameter",
isOptional: true),
Child(name: "AsyncKeyword",
kind: "KeywordToken",
isOptional: true,
tokenChoices: [
"Keyword"
],
textChoices: [
"async"
]),
Child(name: "ThrowsKeyword",
kind: "KeywordToken",
isOptional: true,
tokenChoices: [
"Keyword"
],
textChoices: [
"throws",
"rethrows"
]),
Child(name: "EffectSpecifiers",
kind: "DeclEffectSpecifiers",
isOptional: true),
Child(name: "Body",
kind: "CodeBlock",
isOptional: true)
Expand Down
34 changes: 5 additions & 29 deletions CodeGeneration/Sources/SyntaxSupport/gyb_generated/ExprNodes.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -303,17 +303,8 @@ public let EXPR_NODES: [Node] = [
nameForDiagnostics: nil,
kind: "Expr",
children: [
Child(name: "AsyncKeyword",
kind: "KeywordToken",
isOptional: true,
tokenChoices: [
"Keyword"
],
textChoices: [
"async"
]),
Child(name: "ThrowsToken",
kind: "ThrowsToken",
Child(name: "EffectSpecifiers",
kind: "TypeEffectSpecifiers",
isOptional: true),
Child(name: "ArrowToken",
kind: "ArrowToken",
Expand Down Expand Up @@ -796,24 +787,9 @@ public let EXPR_NODES: [Node] = [
Child(name: "Input",
kind: "ParameterClause")
]),
Child(name: "AsyncKeyword",
kind: "KeywordToken",
isOptional: true,
tokenChoices: [
"Keyword"
],
textChoices: [
"async"
]),
Child(name: "ThrowsTok",
kind: "KeywordToken",
isOptional: true,
tokenChoices: [
"Keyword"
],
textChoices: [
"throws"
]),
Child(name: "EffectSpecifiers",
kind: "TypeEffectSpecifiers",
isOptional: true),
Child(name: "Output",
kind: "ReturnClause",
isOptional: true),
Expand Down
9 changes: 9 additions & 0 deletions CodeGeneration/Sources/SyntaxSupport/gyb_generated/Traits.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -69,4 +69,13 @@ public let TRAITS: [Trait] = [
Child(name: "Statements", kind: "CodeBlockItemList"),
]
),
Trait(traitName: "EffectSpecifiers",
children: [
Child(name: "UnexpectedBeforeAsyncSpecifier", kind: "UnexpectedNodes", isOptional: true),
Child(name: "AsyncSpecifier", kind: "KeywordToken", isOptional: true),
Child(name: "UnexpectedBetweenAsyncSpecifierAndThrowsSpecifier", kind: "UnexpectedNodes", isOptional: true),
Child(name: "ThrowsSpecifier", kind: "KeywordToken", isOptional: true),
Child(name: "UnexpectedAfterThrowsSpecifier", kind: "UnexpectedNodes", isOptional: true),
]
),
]
29 changes: 5 additions & 24 deletions CodeGeneration/Sources/SyntaxSupport/gyb_generated/TypeNodes.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -330,30 +330,11 @@ public let TYPE_NODES: [Node] = [
tokenChoices: [
"RightParen"
]),
Child(name: "AsyncKeyword",
kind: "KeyworkToken",
isOptional: true,
textChoices: [
"async"
]),
Child(name: "ThrowsOrRethrowsKeyword",
kind: "KeywordToken",
isOptional: true,
tokenChoices: [
"Keyword"
],
textChoices: [
"throws",
"rethrows",
"throw"
]),
Child(name: "Arrow",
kind: "ArrowToken",
tokenChoices: [
"Arrow"
]),
Child(name: "ReturnType",
kind: "Type")
Child(name: "EffectSpecifiers",
kind: "TypeEffectSpecifiers",
isOptional: true),
Child(name: "Output",
kind: "ReturnClause")
]),

Node(name: "AttributedType",
Expand Down
1 change: 1 addition & 0 deletions Sources/SwiftParser/CMakeLists.txt
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Expand Up @@ -23,6 +23,7 @@ add_swift_host_library(SwiftParser
RawTokenKindMatch.swift
RawTokenKindSubset.swift
Recovery.swift
Specifiers.swift
Statements.swift
StringLiterals.swift
SyntaxUtils.swift
Expand Down
92 changes: 16 additions & 76 deletions Sources/SwiftParser/Declarations.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -1217,26 +1217,25 @@ extension Parser {
}

/// If a `throws` keyword appears right in front of the `arrow`, it is returned as `misplacedThrowsKeyword` so it can be synthesized in front of the arrow.
@_spi(RawSyntax)
public mutating func parseFunctionReturnClause() -> (returnClause: RawReturnClauseSyntax, misplacedThrowsKeyword: RawTokenSyntax?) {
mutating func parseFunctionReturnClause<S: RawEffectSpecifiersTrait>(effectSpecifiers: inout S?, allowNamedOpaqueResultType: Bool) -> RawReturnClauseSyntax {
let (unexpectedBeforeArrow, arrow) = self.expect(.arrow)
var misplacedThrowsKeyword: RawTokenSyntax? = nil
let unexpectedBeforeReturnType: RawUnexpectedNodesSyntax?
if let throwsKeyword = self.consume(ifAny: [.keyword(.rethrows), .keyword(.throws)]) {
misplacedThrowsKeyword = throwsKeyword
unexpectedBeforeReturnType = RawUnexpectedNodesSyntax(elements: [RawSyntax(throwsKeyword)], arena: self.arena)
let unexpectedBeforeReturnType = self.parseMisplacedEffectSpecifiers(&effectSpecifiers)
let result: RawTypeSyntax
if allowNamedOpaqueResultType {
result = self.parseResultType()
} else {
unexpectedBeforeReturnType = nil
result = self.parseType()
}
let result = self.parseResultType()
let unexpectedAfterReturnType = self.parseMisplacedEffectSpecifiers(&effectSpecifiers)
let returnClause = RawReturnClauseSyntax(
unexpectedBeforeArrow,
arrow: arrow,
unexpectedBeforeReturnType,
returnType: result,
unexpectedAfterReturnType,
arena: self.arena
)
return (returnClause, misplacedThrowsKeyword)
return returnClause
}
}

Expand Down Expand Up @@ -1318,32 +1317,18 @@ extension Parser {
public mutating func parseFunctionSignature() -> RawFunctionSignatureSyntax {
let input = self.parseParameterClause(for: .functionParameters)

let async: RawTokenSyntax?
if let asyncTok = self.consume(if: .keyword(.async)) {
async = asyncTok
} else if let reasync = self.consume(if: .keyword(.reasync)) {
async = reasync
} else {
async = nil
}

var throwsKeyword = self.consume(ifAny: [.keyword(.throws), .keyword(.rethrows)])
var effectSpecifiers = self.parseDeclEffectSpecifiers()

let output: RawReturnClauseSyntax?
if self.at(.arrow) {
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Contributor

@bnbarham bnbarham Jan 24, 2023 •
edited
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I imagine we wouldn't be recovering well from random junk before the arrow right now? Could this use canRecoverTo instead?

EDIT: With a low precedence so we don't walk past eg. func etc.

let result = self.parseFunctionReturnClause()
output = result.returnClause
if let misplacedThrowsKeyword = result.misplacedThrowsKeyword, throwsKeyword == nil {
throwsKeyword = RawTokenSyntax(missing: misplacedThrowsKeyword.tokenKind, arena: self.arena)
}
output = self.parseFunctionReturnClause(effectSpecifiers: &effectSpecifiers, allowNamedOpaqueResultType: true)
} else {
output = nil
}

return RawFunctionSignatureSyntax(
input: input,
asyncOrReasyncKeyword: async,
throwsOrRethrowsKeyword: throwsKeyword,
effectSpecifiers: effectSpecifiers,
output: output,
arena: self.arena
)
Expand Down Expand Up @@ -1384,7 +1369,8 @@ extension Parser {

let indices = self.parseParameterClause(for: .indices)

let result = self.parseFunctionReturnClause().returnClause
var misplacedEffectSpecifiers: RawDeclEffectSpecifiersSyntax?
let result = self.parseFunctionReturnClause(effectSpecifiers: &misplacedEffectSpecifiers, allowNamedOpaqueResultType: true)

// Parse a 'where' clause if present.
let genericWhereClause: RawGenericWhereClauseSyntax?
Expand Down Expand Up @@ -1588,41 +1574,6 @@ extension Parser {
)
}

@_spi(RawSyntax)
public mutating func parseEffectsSpecifier() -> RawTokenSyntax? {
// 'async'
if let async = self.consume(if: .keyword(.async)) {
return async
}

// 'reasync'
if let reasync = self.consume(if: .keyword(.reasync)) {
return reasync
}

// 'throws'/'rethrows'
if let throwsRethrows = self.consume(ifAny: [.keyword(.throws), .keyword(.rethrows)]) {
return throwsRethrows
}

// diagnose 'throw'/'try'.
if let throwTry = self.consume(ifAny: [.keyword(.throw), .keyword(.try)], allowTokenAtStartOfLine: false) {
return throwTry
}

return nil
}

@_spi(RawSyntax)
public mutating func parseEffectsSpecifiers() -> [RawTokenSyntax] {
var specifiers = [RawTokenSyntax]()
var loopProgress = LoopProgressCondition()
while let specifier = self.parseEffectsSpecifier(), loopProgress.evaluate(currentToken) {
specifiers.append(specifier)
}
return specifiers
}

/// Parse an accessor.
mutating func parseAccessorDecl() -> RawAccessorDeclSyntax {
let forcedHandle = TokenConsumptionHandle(tokenKind: .keyword(.get), missing: true)
Expand Down Expand Up @@ -1669,26 +1620,15 @@ extension Parser {
parameter = nil
}

// Next, parse effects specifiers. While it's only valid to have them
// on 'get' accessors, we also emit diagnostics if they show up on others.
let asyncKeyword: RawTokenSyntax?
let throwsKeyword: RawTokenSyntax?
if self.at(anyIn: EffectsSpecifier.self) != nil {
asyncKeyword = self.parseEffectsSpecifier()
throwsKeyword = self.parseEffectsSpecifier()
} else {
asyncKeyword = nil
throwsKeyword = nil
}
let effectSpecifiers = self.parseDeclEffectSpecifiers()

let body = self.parseOptionalCodeBlock()
return RawAccessorDeclSyntax(
attributes: introducer.attributes,
modifier: introducer.modifier,
accessorKind: introducer.token,
parameter: parameter,
asyncKeyword: asyncKeyword,
throwsKeyword: throwsKeyword,
effectSpecifiers: effectSpecifiers,
body: body,
arena: self.arena
)
Expand Down
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