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ParsePattern.cpp
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//===--- ParsePattern.cpp - Swift Language Parser for Patterns ------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// Pattern Parsing and AST Building
//
//===----------------------------------------------------------------------===//
#include "swift/Parse/Parser.h"
#include "swift/AST/ASTWalker.h"
#include "swift/AST/GenericParamList.h"
#include "swift/AST/Initializer.h"
#include "swift/AST/Module.h"
#include "swift/AST/SourceFile.h"
#include "swift/AST/TypeRepr.h"
#include "swift/Basic/StringExtras.h"
#include "swift/Parse/IDEInspectionCallbacks.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/Support/SaveAndRestore.h"
using namespace swift;
/// Determine the kind of a default argument given a parsed
/// expression that has not yet been type-checked.
static DefaultArgumentKind getDefaultArgKind(Expr *init) {
if (!init)
return DefaultArgumentKind::None;
// Parse an as-written 'nil' expression as the special NilLiteral kind,
// which is emitted by the caller and can participate in rethrows
// checking.
if (isa<NilLiteralExpr>(init))
return DefaultArgumentKind::NilLiteral;
auto magic = dyn_cast<MagicIdentifierLiteralExpr>(init);
if (!magic)
return DefaultArgumentKind::Normal;
switch (magic->getKind()) {
#define MAGIC_IDENTIFIER(NAME, STRING, SYNTAX_KIND) \
case MagicIdentifierLiteralExpr::NAME: return DefaultArgumentKind::NAME;
#include "swift/AST/MagicIdentifierKinds.def"
}
llvm_unreachable("Unhandled MagicIdentifierLiteralExpr in switch.");
}
void Parser::DefaultArgumentInfo::setFunctionContext(
DeclContext *DC, ParameterList *paramList){
for (auto context : ParsedContexts) {
context->changeFunction(DC, paramList);
}
}
static ParserStatus parseDefaultArgument(
Parser &P, Parser::DefaultArgumentInfo *defaultArgs, unsigned argIndex,
Expr *&init, bool &hasInheritedDefaultArg,
Parser::ParameterContextKind paramContext) {
assert(P.Tok.is(tok::equal) ||
(P.Tok.isBinaryOperator() && P.Tok.getText() == "=="));
SourceLoc equalLoc = P.consumeToken();
if (P.SF.Kind == SourceFileKind::Interface) {
// Swift module interfaces don't synthesize inherited initializers and
// instead include them explicitly in subclasses. Since the
// \c DefaultArgumentKind of these initializers is \c Inherited, this is
// represented textually as `= super` in the interface.
// If we're in a module interface and the default argument is exactly
// `super` (i.e. the token after that is `,` or `)` which end a parameter)
// report an inherited default argument to the caller and return.
if (P.Tok.is(tok::kw_super) && P.peekToken().isAny(tok::comma, tok::r_paren)) {
hasInheritedDefaultArg = true;
P.consumeToken(tok::kw_super);
defaultArgs->HasDefaultArgument = true;
return ParserStatus();
}
}
// Enter a fresh default-argument context with a meaningless parent.
// We'll change the parent to the function later after we've created
// that declaration.
auto initDC = new (P.Context) DefaultArgumentInitializer(P.CurDeclContext,
argIndex);
Parser::ParseFunctionBody initScope(P, initDC);
ParserResult<Expr> initR = P.parseExpr(diag::expected_init_value);
// Record the default-argument context if we're supposed to accept default
// arguments here.
if (defaultArgs) {
defaultArgs->ParsedContexts.push_back(initDC);
}
Diag<> diagID = { DiagID() };
switch (paramContext) {
case Parser::ParameterContextKind::Function:
case Parser::ParameterContextKind::Operator:
case Parser::ParameterContextKind::Initializer:
case Parser::ParameterContextKind::EnumElement:
case Parser::ParameterContextKind::Subscript:
case Parser::ParameterContextKind::Macro:
break;
case Parser::ParameterContextKind::Closure:
diagID = diag::no_default_arg_closure;
break;
case Parser::ParameterContextKind::Curried:
diagID = diag::no_default_arg_curried;
break;
}
assert((diagID.ID != DiagID()) == !defaultArgs &&
"Default arguments specified for an unexpected parameter list kind");
if (diagID.ID != DiagID()) {
auto inFlight = P.diagnose(equalLoc, diagID);
if (initR.isNonNull())
inFlight.fixItRemove(SourceRange(equalLoc, initR.get()->getEndLoc()));
return ParserStatus();
}
defaultArgs->HasDefaultArgument = true;
if (initR.hasCodeCompletion()) {
init = initR.get();
return makeParserCodeCompletionStatus();
}
if (initR.isNull())
return makeParserError();
init = initR.get();
return ParserStatus();
}
/// Determine whether we are at the start of a parameter name when
/// parsing a parameter.
bool Parser::startsParameterName(bool isClosure) {
// To have a parameter name here, we need a name.
if (!Tok.canBeArgumentLabel())
return false;
// If the next token is ':', this is a name.
const auto &nextTok = peekToken();
if (nextTok.is(tok::colon))
return true;
// If the next token can be an argument label, we might have a name.
if (nextTok.canBeArgumentLabel()) {
// If the first name wasn't a contextual keyword, we're done.
if (!Tok.isContextualKeyword("isolated") &&
!Tok.isContextualKeyword("some") &&
!Tok.isContextualKeyword("any") &&
!Tok.isContextualKeyword("each") &&
!Tok.isContextualKeyword("__shared") &&
!Tok.isContextualKeyword("__owned") &&
!Tok.isContextualKeyword("borrowing") &&
!Tok.isContextualKeyword("consuming") &&
!Tok.is(tok::kw_repeat))
return true;
// Parameter specifiers can be an argument label, but they're also
// contextual keywords, so look ahead one more token (two total) and see
// if we have a ':' that would
// indicate that this is an argument label.
return lookahead<bool>(2, [&](CancellableBacktrackingScope &) {
if (Tok.is(tok::colon))
return true; // isolated :
return Tok.canBeArgumentLabel() && nextTok.is(tok::colon);
});
}
if (isOptionalToken(nextTok)
|| isImplicitlyUnwrappedOptionalToken(nextTok))
return false;
// The identifier could be a name or it could be a type. In a closure, we
// assume it's a name, because the type can be inferred. Elsewhere, we
// assume it's a type.
return isClosure;
}
ParserStatus
Parser::parseParameterClause(SourceLoc &leftParenLoc,
SmallVectorImpl<ParsedParameter> ¶ms,
SourceLoc &rightParenLoc,
DefaultArgumentInfo *defaultArgs,
ParameterContextKind paramContext) {
assert(params.empty() && leftParenLoc.isInvalid() &&
rightParenLoc.isInvalid() && "Must start with empty state");
// Consume the starting '(';
leftParenLoc = consumeToken(tok::l_paren);
// Trivial case: empty parameter list.
if (Tok.is(tok::r_paren)) {
rightParenLoc = consumeToken(tok::r_paren);
// Per SE-0155, enum elements may not have empty parameter lists.
if (paramContext == ParameterContextKind::EnumElement) {
decltype(diag::enum_element_empty_arglist) diagnostic;
if (Context.isSwiftVersionAtLeast(5)) {
diagnostic = diag::enum_element_empty_arglist;
} else {
diagnostic = diag::enum_element_empty_arglist_swift4;
}
diagnose(leftParenLoc, diagnostic)
.highlight({leftParenLoc, rightParenLoc});
diagnose(leftParenLoc, diag::enum_element_empty_arglist_delete)
.fixItRemoveChars(leftParenLoc,
Lexer::getLocForEndOfToken(SourceMgr, rightParenLoc));
diagnose(leftParenLoc, diag::enum_element_empty_arglist_add_void)
.fixItInsertAfter(leftParenLoc, "Void");
}
return ParserStatus();
}
// Parse the parameter list.
bool isClosure = paramContext == ParameterContextKind::Closure;
return parseList(tok::r_paren, leftParenLoc, rightParenLoc,
/*AllowSepAfterLast=*/false,
diag::expected_rparen_parameter,
[&]() -> ParserStatus {
ParsedParameter param;
ParserStatus status;
SourceLoc StartLoc = Tok.getLoc();
unsigned defaultArgIndex = defaultArgs ? defaultArgs->NextIndex++ : 0;
// Attributes.
if (paramContext != ParameterContextKind::EnumElement) {
auto AttrStatus = parseDeclAttributeList(param.Attrs);
if (AttrStatus.hasCodeCompletion()) {
if (this->CodeCompletionCallbacks)
this->CodeCompletionCallbacks->setAttrTargetDeclKind(DeclKind::Param);
status.setHasCodeCompletionAndIsError();
}
}
{
// ('inout' | '__shared' | '__owned' | isolated)?
bool hasSpecifier = false;
while (Tok.is(tok::kw_inout)
|| (canHaveParameterSpecifierContextualKeyword()
&& (Tok.isContextualKeyword("__shared")
|| Tok.isContextualKeyword("__owned")
|| Tok.isContextualKeyword("borrowing")
|| Tok.isContextualKeyword("consuming")
|| Tok.isContextualKeyword("isolated")
|| Tok.isContextualKeyword("_const")))) {
// is this token the identifier of an argument label? `inout` is a
// reserved keyword but the other modifiers are not.
if (!Tok.is(tok::kw_inout)) {
bool partOfArgumentLabel = lookahead<bool>(1, [&](CancellableBacktrackingScope &) {
if (Tok.is(tok::colon))
return true; // isolated :
return Tok.canBeArgumentLabel() && peekToken().is(tok::colon);
});
if (partOfArgumentLabel)
break;
}
if (Tok.isContextualKeyword("isolated")) {
// did we already find an 'isolated' type modifier?
if (param.IsolatedLoc.isValid()) {
diagnose(Tok, diag::parameter_specifier_repeated)
.fixItRemove(Tok.getLoc());
consumeToken();
continue;
}
// consume 'isolated' as type modifier
param.IsolatedLoc = consumeToken();
continue;
}
if (Tok.isContextualKeyword("_const")) {
param.CompileConstLoc = consumeToken();
continue;
}
if (!hasSpecifier) {
// These cases are handled later when mapping to ParamDecls for
// better fixits.
if (Tok.is(tok::kw_inout)) {
param.SpecifierKind = ParamDecl::Specifier::InOut;
param.SpecifierLoc = consumeToken();
} else if (Tok.isContextualKeyword("borrowing")) {
param.SpecifierKind = ParamDecl::Specifier::Borrowing;
param.SpecifierLoc = consumeToken();
} else if (Tok.isContextualKeyword("consuming")) {
param.SpecifierKind = ParamDecl::Specifier::Consuming;
param.SpecifierLoc = consumeToken();
} else if (Tok.isContextualKeyword("__shared")) {
param.SpecifierKind = ParamDecl::Specifier::LegacyShared;
param.SpecifierLoc = consumeToken();
} else if (Tok.isContextualKeyword("__owned")) {
param.SpecifierKind = ParamDecl::Specifier::LegacyOwned;
param.SpecifierLoc = consumeToken();
}
hasSpecifier = true;
} else {
// Redundant specifiers are fairly common, recognize, reject, and
// recover from this gracefully.
diagnose(Tok, diag::parameter_specifier_repeated)
.fixItRemove(Tok.getLoc());
consumeToken();
}
}
}
// If let or var is being used as an argument label, allow it but
// generate a warning.
if (!isClosure &&
(Tok.isAny(tok::kw_let, tok::kw_var) ||
(Context.LangOpts.hasFeature(Feature::ReferenceBindings) &&
Tok.isAny(tok::kw_inout)))) {
diagnose(Tok, diag::parameter_let_var_as_attr, Tok.getText())
.fixItReplace(Tok.getLoc(), "`" + Tok.getText().str() + "`");
}
if (startsParameterName(isClosure)) {
// identifier-or-none for the first name
param.FirstNameLoc = consumeArgumentLabel(param.FirstName,
/*diagnoseDollarPrefix=*/!isClosure);
// identifier-or-none? for the second name
if (Tok.canBeArgumentLabel())
param.SecondNameLoc = consumeArgumentLabel(param.SecondName,
/*diagnoseDollarPrefix=*/true);
// Operators, closures, and enum elements cannot have API names.
if ((paramContext == ParameterContextKind::Operator ||
paramContext == ParameterContextKind::Closure ||
paramContext == ParameterContextKind::EnumElement) &&
!param.FirstName.empty() &&
param.SecondNameLoc.isValid()) {
enum KeywordArgumentDiagnosticContextKind {
Operator = 0,
Closure = 1,
EnumElement = 2,
} diagContextKind;
switch (paramContext) {
case ParameterContextKind::Operator:
diagContextKind = Operator;
break;
case ParameterContextKind::Closure:
diagContextKind = Closure;
break;
case ParameterContextKind::EnumElement:
diagContextKind = EnumElement;
break;
default:
llvm_unreachable("Unhandled parameter context kind!");
}
diagnose(param.FirstNameLoc, diag::parameter_operator_keyword_argument,
unsigned(diagContextKind))
.fixItRemoveChars(param.FirstNameLoc, param.SecondNameLoc);
param.FirstName = param.SecondName;
param.FirstNameLoc = param.SecondNameLoc;
param.SecondName = Identifier();
param.SecondNameLoc = SourceLoc();
}
// (':' type)?
if (consumeIf(tok::colon)) {
auto type = parseType(diag::expected_parameter_type);
status |= type;
param.Type = type.getPtrOrNull();
// If we didn't parse a type, then we already diagnosed that the type
// was invalid. Remember that.
if (type.isNull() && !type.hasCodeCompletion())
param.isInvalid = true;
} else if (paramContext != Parser::ParameterContextKind::Closure) {
diagnose(Tok, diag::expected_parameter_colon);
param.isInvalid = true;
}
} else {
// Otherwise, we have invalid code. Check to see if this looks like a
// type. If so, diagnose it as a common error.
bool isBareType = false;
{
BacktrackingScope backtrack(*this);
isBareType = canParseType() && Tok.isAny(tok::comma, tok::r_paren,
tok::equal);
}
if (isBareType && paramContext == ParameterContextKind::EnumElement) {
auto type = parseType(diag::expected_parameter_type);
status |= type;
param.Type = type.getPtrOrNull();
param.FirstName = Identifier();
param.FirstNameLoc = SourceLoc();
param.SecondName = Identifier();
param.SecondNameLoc = SourceLoc();
} else if (isBareType && !Tok.is(tok::code_complete)) {
// Otherwise, if this is a bare type, then the user forgot to name the
// parameter, e.g. "func foo(Int) {}"
// Don't enter this case if the element could only be parsed as a bare
// type because a code completion token is positioned here. In this case
// the user is about to type the parameter label and we shouldn't
// suggest types.
SourceLoc typeStartLoc = Tok.getLoc();
auto type = parseType(diag::expected_parameter_type);
status |= type;
param.Type = type.getPtrOrNull();
// If this is a closure declaration, what is going
// on is most likely argument destructuring, we are going
// to diagnose that after all of the parameters are parsed.
if (param.Type) {
// Mark current parameter type as invalid so it is possible
// to diagnose it as destructuring of the closure parameter list.
param.isPotentiallyDestructured = true;
if (!isClosure) {
// Unnamed parameters must be written as "_: Type".
diagnose(typeStartLoc, diag::parameter_unnamed)
.fixItInsert(typeStartLoc, "_: ");
} else {
// Unnamed parameters were accidentally possibly accepted after
// SE-110 depending on the kind of declaration. We now need to
// warn about the misuse of this syntax and offer to
// fix it.
// An exception to this rule is when the type is declared with type sugar
// Reference: https://github.com/apple/swift/issues/54133
if (isa<OptionalTypeRepr>(param.Type)
|| isa<ImplicitlyUnwrappedOptionalTypeRepr>(param.Type)) {
diagnose(typeStartLoc, diag::parameter_unnamed)
.fixItInsert(typeStartLoc, "_: ");
} else {
diagnose(typeStartLoc, diag::parameter_unnamed_warn)
.fixItInsert(typeStartLoc, "_: ");
}
}
}
} else {
// Otherwise, we're not sure what is going on, but this doesn't smell
// like a parameter.
diagnose(Tok, diag::expected_parameter_name);
param.isInvalid = true;
param.FirstNameLoc = Tok.getLoc();
TokReceiver->registerTokenKindChange(param.FirstNameLoc,
tok::identifier);
status.setIsParseError();
}
}
// If this parameter had an ellipsis, check it has a TypeRepr.
if (Tok.isEllipsis()) {
if (param.Type == nullptr && !param.isInvalid) {
diagnose(Tok, diag::untyped_pattern_ellipsis);
consumeToken();
}
}
// ('=' expr) or ('==' expr)?
bool isEqualBinaryOperator =
Tok.isBinaryOperator() && Tok.getText() == "==";
if (Tok.is(tok::equal) || isEqualBinaryOperator) {
SourceLoc EqualLoc = Tok.getLoc();
if (isEqualBinaryOperator) {
diagnose(Tok, diag::expected_assignment_instead_of_comparison_operator)
.fixItReplace(EqualLoc, "=");
}
status |= parseDefaultArgument(
*this, defaultArgs, defaultArgIndex, param.DefaultArg,
param.hasInheritedDefaultArg, paramContext);
}
// If we haven't made progress, don't add the parameter.
if (Tok.getLoc() == StartLoc) {
// If we took a default argument index for this parameter, but didn't add
// one, then give it back.
if (defaultArgs) --defaultArgs->NextIndex;
return status;
}
params.push_back(param);
return status;
});
}
static TypeRepr *
validateParameterWithOwnership(Parser &parser,
Parser::ParsedParameter ¶mInfo,
ParamSpecifier specifier,
bool parsingEnumElt) {
auto type = paramInfo.Type;
auto loc = paramInfo.SpecifierLoc;
// If we're validating an enum element, 'inout' is not allowed
// at all - Sema will catch this for us. In all other contexts, we
// assume the user put 'inout' in the wrong place and offer a fixit.
if (parsingEnumElt) {
return new (parser.Context) OwnershipTypeRepr(type, specifier, loc);
}
if (isa<SpecifierTypeRepr>(type)) {
parser.diagnose(loc, diag::parameter_specifier_repeated).fixItRemove(loc);
} else {
auto specifierName = ParamDecl::getSpecifierSpelling(specifier);
llvm::SmallString<128> replacement(specifierName);
replacement += " ";
parser
.diagnose(loc, diag::parameter_specifier_as_attr_disallowed,
specifierName)
.fixItRemove(loc)
.fixItInsert(type->getStartLoc(), replacement);
type = new (parser.Context) OwnershipTypeRepr(type, specifier, loc);
}
return type;
}
/// Map parsed parameters to a ParameterList.
static ParameterList *
mapParsedParameters(Parser &parser,
SourceLoc leftParenLoc,
MutableArrayRef<Parser::ParsedParameter> params,
SourceLoc rightParenLoc,
SmallVectorImpl<Identifier> *argNames,
Parser::ParameterContextKind paramContext) {
auto &ctx = parser.Context;
// Local function to create a pattern for a single parameter.
auto createParam = [&](Parser::ParsedParameter ¶mInfo,
Identifier argName, SourceLoc argNameLoc,
Identifier paramName, SourceLoc paramNameLoc)
-> ParamDecl * {
auto param = new (ctx) ParamDecl(paramInfo.SpecifierLoc,
argNameLoc, argName,
paramNameLoc, paramName,
parser.CurDeclContext);
param->getAttrs() = paramInfo.Attrs;
bool parsingEnumElt
= (paramContext == Parser::ParameterContextKind::EnumElement);
// If we're not parsing an enum case, lack of a SourceLoc for both
// names indicates the parameter is synthetic.
if (!parsingEnumElt && argNameLoc.isInvalid() && paramNameLoc.isInvalid())
param->setImplicit();
// If we diagnosed this parameter as a parse error, propagate to the decl.
if (paramInfo.isInvalid)
param->setInvalid();
// If we need to diagnose this parameter as a destructuring, propagate that
// to the decl.
// FIXME: This is a terrible way to catch this.
if (paramInfo.isPotentiallyDestructured)
param->setDestructured(true);
// If a type was provided, create the type for the parameter.
if (auto type = paramInfo.Type) {
// If 'inout' was specified, turn the type into an in-out type.
if (paramInfo.SpecifierKind != ParamDecl::Specifier::Default) {
type = validateParameterWithOwnership(parser, paramInfo,
paramInfo.SpecifierKind,
parsingEnumElt);
}
if (paramInfo.IsolatedLoc.isValid()) {
type = new (parser.Context) IsolatedTypeRepr(
type, paramInfo.IsolatedLoc);
param->setIsolated();
}
if (paramInfo.CompileConstLoc.isValid()) {
type = new (parser.Context) CompileTimeConstTypeRepr(
type, paramInfo.CompileConstLoc);
param->setCompileTimeConst();
}
param->setTypeRepr(type);
// Dig through the type to find any attributes or modifiers that are
// associated with the type but should also be reflected on the
// declaration.
{
auto unwrappedType = type;
while (true) {
if (auto *ATR = dyn_cast<AttributedTypeRepr>(unwrappedType)) {
auto &attrs = ATR->getAttrs();
// At this point we actually don't know if that's valid to mark
// this parameter declaration as `autoclosure` because type has
// not been resolved yet - it should either be a function type
// or typealias with underlying function type.
param->setAutoClosure(attrs.has(TypeAttrKind::TAK_autoclosure));
unwrappedType = ATR->getTypeRepr();
continue;
}
if (auto *STR = dyn_cast<SpecifierTypeRepr>(unwrappedType)) {
if (isa<IsolatedTypeRepr>(STR))
param->setIsolated(true);
else if (isa<CompileTimeConstTypeRepr>(STR))
param->setCompileTimeConst(true);
unwrappedType = STR->getBase();
continue;
}
break;
}
}
} else if (paramInfo.SpecifierLoc.isValid()) {
llvm::SmallString<16> specifier;
{
llvm::raw_svector_ostream ss(specifier);
ss << '\'' << ParamDecl::getSpecifierSpelling(paramInfo.SpecifierKind)
<< '\'';
}
parser.diagnose(paramInfo.SpecifierLoc, diag::specifier_must_have_type,
specifier);
paramInfo.SpecifierLoc = SourceLoc();
paramInfo.SpecifierKind = ParamDecl::Specifier::Default;
param->setSpecifier(ParamSpecifier::Default);
} else {
param->setSpecifier(ParamSpecifier::Default);
}
return param;
};
// Collect the elements of the tuple patterns for argument and body
// parameters.
SmallVector<ParamDecl*, 4> elements;
for (auto ¶m : params) {
// Whether the provided name is API by default depends on the parameter
// context.
bool isKeywordArgumentByDefault;
switch (paramContext) {
case Parser::ParameterContextKind::Closure:
case Parser::ParameterContextKind::Subscript:
case Parser::ParameterContextKind::Operator:
isKeywordArgumentByDefault = false;
break;
case Parser::ParameterContextKind::EnumElement:
case Parser::ParameterContextKind::Curried:
case Parser::ParameterContextKind::Initializer:
case Parser::ParameterContextKind::Function:
case Parser::ParameterContextKind::Macro:
isKeywordArgumentByDefault = true;
break;
}
// Create the pattern.
ParamDecl *result = nullptr;
Identifier argName;
Identifier paramName;
if (param.SecondNameLoc.isValid()) {
argName = param.FirstName;
paramName = param.SecondName;
// Both names were provided, so pass them in directly.
result = createParam(param, argName, param.FirstNameLoc,
paramName, param.SecondNameLoc);
// If the first and second names are equivalent and non-empty, and we
// would have an argument label by default, complain.
if (isKeywordArgumentByDefault && param.FirstName == param.SecondName
&& !param.FirstName.empty()) {
parser.diagnose(param.FirstNameLoc,
diag::parameter_extraneous_double_up,
param.FirstName)
.fixItRemoveChars(param.FirstNameLoc, param.SecondNameLoc);
}
} else {
if (isKeywordArgumentByDefault)
argName = param.FirstName;
paramName = param.FirstName;
result = createParam(param, argName, SourceLoc(),
param.FirstName, param.FirstNameLoc);
}
assert (((!param.DefaultArg &&
!param.hasInheritedDefaultArg) ||
paramContext == Parser::ParameterContextKind::Function ||
paramContext == Parser::ParameterContextKind::Operator ||
paramContext == Parser::ParameterContextKind::Initializer ||
paramContext == Parser::ParameterContextKind::EnumElement ||
paramContext == Parser::ParameterContextKind::Subscript ||
paramContext == Parser::ParameterContextKind::Macro) &&
"Default arguments are only permitted on the first param clause");
if (param.DefaultArg) {
DefaultArgumentKind kind = getDefaultArgKind(param.DefaultArg);
result->setDefaultArgumentKind(kind);
result->setDefaultExpr(param.DefaultArg, /*isTypeChecked*/ false);
} else if (param.hasInheritedDefaultArg) {
result->setDefaultArgumentKind(DefaultArgumentKind::Inherited);
}
elements.push_back(result);
if (argNames)
argNames->push_back(argName);
}
return ParameterList::create(ctx, leftParenLoc, elements, rightParenLoc);
}
/// Parse a single parameter-clause.
ParserResult<ParameterList>
Parser::parseSingleParameterClause(ParameterContextKind paramContext,
SmallVectorImpl<Identifier> *namePieces,
DefaultArgumentInfo *defaultArgs) {
if (!Tok.is(tok::l_paren)) {
// If we don't have the leading '(', complain.
Diag<> diagID;
switch (paramContext) {
case ParameterContextKind::Function:
case ParameterContextKind::Operator:
diagID = diag::func_decl_without_paren;
break;
case ParameterContextKind::Subscript:
diagID = diag::expected_lparen_subscript;
break;
case ParameterContextKind::Initializer:
diagID = diag::expected_lparen_initializer;
break;
case ParameterContextKind::Macro:
diagID = diag::expected_lparen_macro;
break;
case ParameterContextKind::EnumElement:
case ParameterContextKind::Closure:
case ParameterContextKind::Curried:
llvm_unreachable("should never be here");
}
{
auto diag = diagnose(Tok, diagID);
if (Tok.isAny(tok::l_brace, tok::arrow, tok::kw_throws, tok::kw_rethrows))
diag.fixItInsertAfter(PreviousLoc, "()");
}
// Create an empty parameter list to recover.
return makeParserErrorResult(
ParameterList::createEmpty(Context, PreviousLoc, PreviousLoc));
}
ParserStatus status;
SmallVector<ParsedParameter, 4> params;
SourceLoc leftParenLoc, rightParenLoc;
// Parse the parameter clause.
status |= parseParameterClause(leftParenLoc, params, rightParenLoc,
defaultArgs, paramContext);
// Turn the parameter clause into argument and body patterns.
auto paramList = mapParsedParameters(*this, leftParenLoc, params,
rightParenLoc, namePieces, paramContext);
return makeParserResult(status, paramList);
}
/// Parse function arguments.
///
/// Emits a special diagnostic if there are multiple parameter lists,
/// but otherwise is identical to parseSingleParameterClause().
ParserStatus
Parser::parseFunctionArguments(SmallVectorImpl<Identifier> &NamePieces,
ParameterList *&BodyParams,
ParameterContextKind paramContext,
DefaultArgumentInfo &DefaultArgs) {
// Parse parameter-clauses.
ParserStatus status;
auto FirstParameterClause
= parseSingleParameterClause(paramContext, &NamePieces, &DefaultArgs);
status |= FirstParameterClause;
BodyParams = FirstParameterClause.get();
bool MultipleParameterLists = false;
while (Tok.is(tok::l_paren)) {
MultipleParameterLists = true;
auto CurriedParameterClause
= parseSingleParameterClause(ParameterContextKind::Curried);
status |= CurriedParameterClause;
}
// If the decl uses currying syntax, complain that syntax has gone away.
if (MultipleParameterLists) {
diagnose(BodyParams->getStartLoc(),
diag::parameter_curry_syntax_removed);
}
return status;
}
/// Parse a function definition signature.
/// func-signature:
/// func-arguments ('async'|'reasync')? func-throws? func-signature-result?
/// func-signature-result:
/// '->' type
///
/// Note that this leaves retType as null if unspecified.
ParserStatus
Parser::parseFunctionSignature(DeclBaseName SimpleName,
DeclName &FullName,
ParameterList *&bodyParams,
DefaultArgumentInfo &defaultArgs,
SourceLoc &asyncLoc,
bool &reasync,
SourceLoc &throwsLoc,
bool &rethrows,
TypeRepr *&retType) {
SmallVector<Identifier, 4> NamePieces;
ParserStatus Status;
ParameterContextKind paramContext = SimpleName.isOperator()
? ParameterContextKind::Operator
: (SimpleName == DeclBaseName::createConstructor()
? ParameterContextKind::Initializer
: ParameterContextKind::Function);
Status |= parseFunctionArguments(NamePieces, bodyParams, paramContext,
defaultArgs);
FullName = DeclName(Context, SimpleName, NamePieces);
// Check for the 'async' and 'throws' keywords.
reasync = false;
rethrows = false;
Status |= parseEffectsSpecifiers(SourceLoc(),
asyncLoc, &reasync,
throwsLoc, &rethrows);
// If there's a trailing arrow, parse the rest as the result type.
SourceLoc arrowLoc;
if (Tok.isAny(tok::arrow, tok::colon)) {
if (!consumeIf(tok::arrow, arrowLoc)) {
// FixIt ':' to '->'.
diagnose(Tok, diag::func_decl_expected_arrow)
.fixItReplace(Tok.getLoc(), " -> ");
arrowLoc = consumeToken(tok::colon);
}
// Check for effect specifiers after the arrow, but before the return type,
// and correct it.
parseEffectsSpecifiers(arrowLoc, asyncLoc, &reasync, throwsLoc, &rethrows);
ParserResult<TypeRepr> ResultType =
parseDeclResultType(diag::expected_type_function_result);
retType = ResultType.getPtrOrNull();
Status |= ResultType;
if (Status.isErrorOrHasCompletion())
return Status;
// Check for effect specifiers after the type and correct it.
parseEffectsSpecifiers(arrowLoc, asyncLoc, &reasync, throwsLoc, &rethrows);
} else {
// Otherwise, we leave retType null.
retType = nullptr;
}
return Status;
}
bool Parser::isEffectsSpecifier(const Token &T) {
// NOTE: If this returns 'true', that token must be handled in
// 'parseEffectsSpecifiers()'.
if (T.isContextualKeyword("async") ||
(T.isContextualKeyword("await") && !T.isAtStartOfLine()) ||
T.isContextualKeyword("reasync"))
return true;
if (T.isAny(tok::kw_throws, tok::kw_rethrows) ||
(T.isAny(tok::kw_throw, tok::kw_try) && !T.isAtStartOfLine()))
return true;
return false;
}
ParserStatus Parser::parseEffectsSpecifiers(SourceLoc existingArrowLoc,
SourceLoc &asyncLoc,
bool *reasync,
SourceLoc &throwsLoc,
bool *rethrows) {
ParserStatus status;
while (true) {
// 'async'
bool isReasync = (shouldParseExperimentalConcurrency() &&
Tok.isContextualKeyword("reasync"));
if (Tok.isContextualKeyword("async") ||
isReasync) {
if (asyncLoc.isValid()) {
diagnose(Tok, diag::duplicate_effects_specifier, Tok.getText())
.highlight(asyncLoc)
.fixItRemove(Tok.getLoc());
} else if (!reasync && isReasync) {
// Replace 'reasync' with 'async' unless it's allowed.
diagnose(Tok, diag::reasync_function_type)
.fixItReplace(Tok.getLoc(), "async");
} else if (existingArrowLoc.isValid()) {
SourceLoc insertLoc = existingArrowLoc;
if (throwsLoc.isValid() &&
SourceMgr.isBeforeInBuffer(throwsLoc, insertLoc))
insertLoc = throwsLoc;
diagnose(Tok, diag::async_or_throws_in_wrong_position,
(reasync && isReasync) ? "reasync" : "async")
.fixItRemove(Tok.getLoc())
.fixItInsert(insertLoc,
(reasync && isReasync) ? "reasync " : "async ");
} else if (throwsLoc.isValid()) {
// 'async' cannot be after 'throws'.
assert(existingArrowLoc.isInvalid());
diagnose(Tok, diag::async_after_throws,
reasync && isReasync,
rethrows && *rethrows)
.fixItRemove(Tok.getLoc())
.fixItInsert(throwsLoc, isReasync ? "reasync " : "async ");
}
if (asyncLoc.isInvalid()) {
Tok.setKind(tok::contextual_keyword);
if (reasync)
*reasync = isReasync;
asyncLoc = Tok.getLoc();
}
consumeToken();
continue;
}
// diagnose 'await'
if (Tok.isContextualKeyword("await") && !Tok.isAtStartOfLine()) {
diagnose(Tok, diag::await_in_function_type)
.fixItReplace(Tok.getLoc(), "async");
consumeToken();
continue;
}
// 'throws'/'rethrows', or diagnose 'throw'/'try'.
if (Tok.isAny(tok::kw_throws, tok::kw_rethrows) ||
(Tok.isAny(tok::kw_throw, tok::kw_try) && !Tok.isAtStartOfLine())) {
bool isRethrows = Tok.is(tok::kw_rethrows);
if (throwsLoc.isValid()) {
diagnose(Tok, diag::duplicate_effects_specifier, Tok.getText())
.highlight(throwsLoc)
.fixItRemove(Tok.getLoc());
} else if (Tok.isAny(tok::kw_throw, tok::kw_try)) {
// Replace 'throw' or 'try' with 'throws'.
diagnose(Tok, diag::throw_in_function_type)
.fixItReplace(Tok.getLoc(), "throws");
} else if (!rethrows && isRethrows) {
// Replace 'rethrows' with 'throws' unless it's allowed.
diagnose(Tok, diag::rethrowing_function_type)
.fixItReplace(Tok.getLoc(), "throws");
} else if (existingArrowLoc.isValid()) {
diagnose(Tok, diag::async_or_throws_in_wrong_position, Tok.getText())
.fixItRemove(Tok.getLoc())
.fixItInsert(existingArrowLoc, (Tok.getText() + " ").str());
}
if (throwsLoc.isInvalid()) {
if (rethrows)
*rethrows = isRethrows;
throwsLoc = Tok.getLoc();
}
consumeToken();
continue;
}
// Code completion.
if (Tok.is(tok::code_complete) && !Tok.isAtStartOfLine() &&
!existingArrowLoc.isValid()) {
if (CodeCompletionCallbacks) {
CodeCompletionCallbacks->completeEffectsSpecifier(asyncLoc.isValid(),
throwsLoc.isValid());
}
consumeToken(tok::code_complete);
status.setHasCodeCompletionAndIsError();
continue;
}
break;
}
return status;