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llvm-project/clang/lib/Parse/ParseTemplate.cpp

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//===--- ParseTemplate.cpp - Template Parsing -----------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements parsing of C++ templates.
//
//===----------------------------------------------------------------------===//
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/ExprCXX.h"
#include "clang/Parse/ParseDiagnostic.h"
#include "clang/Parse/Parser.h"
#include "clang/Parse/RAIIObjectsForParser.h"
#include "clang/Sema/DeclSpec.h"
#include "clang/Sema/ParsedTemplate.h"
#include "clang/Sema/Scope.h"
#include "llvm/Support/TimeProfiler.h"
using namespace clang;
/// Re-enter a possible template scope, creating as many template parameter
/// scopes as necessary.
/// \return The number of template parameter scopes entered.
unsigned Parser::ReenterTemplateScopes(MultiParseScope &S, Decl *D) {
return Actions.ActOnReenterTemplateScope(D, [&] {
S.Enter(Scope::TemplateParamScope);
return Actions.getCurScope();
});
}
/// Parse a template declaration, explicit instantiation, or
/// explicit specialization.
Decl *Parser::ParseDeclarationStartingWithTemplate(
DeclaratorContext Context, SourceLocation &DeclEnd,
ParsedAttributes &AccessAttrs, AccessSpecifier AS) {
ObjCDeclContextSwitch ObjCDC(*this);
if (Tok.is(tok::kw_template) && NextToken().isNot(tok::less)) {
return ParseExplicitInstantiation(Context, SourceLocation(), ConsumeToken(),
DeclEnd, AccessAttrs, AS);
}
return ParseTemplateDeclarationOrSpecialization(Context, DeclEnd, AccessAttrs,
AS);
}
/// Parse a template declaration or an explicit specialization.
///
/// Template declarations include one or more template parameter lists
/// and either the function or class template declaration. Explicit
/// specializations contain one or more 'template < >' prefixes
/// followed by a (possibly templated) declaration. Since the
/// syntactic form of both features is nearly identical, we parse all
/// of the template headers together and let semantic analysis sort
/// the declarations from the explicit specializations.
///
/// template-declaration: [C++ temp]
/// 'export'[opt] 'template' '<' template-parameter-list '>' declaration
///
/// template-declaration: [C++2a]
/// template-head declaration
/// template-head concept-definition
///
/// TODO: requires-clause
/// template-head: [C++2a]
/// 'template' '<' template-parameter-list '>'
/// requires-clause[opt]
///
/// explicit-specialization: [ C++ temp.expl.spec]
/// 'template' '<' '>' declaration
Decl *Parser::ParseTemplateDeclarationOrSpecialization(
DeclaratorContext Context, SourceLocation &DeclEnd,
ParsedAttributes &AccessAttrs, AccessSpecifier AS) {
assert(Tok.isOneOf(tok::kw_export, tok::kw_template) &&
"Token does not start a template declaration.");
MultiParseScope TemplateParamScopes(*this);
// Tell the action that names should be checked in the context of
// the declaration to come.
ParsingDeclRAIIObject
ParsingTemplateParams(*this, ParsingDeclRAIIObject::NoParent);
// Parse multiple levels of template headers within this template
// parameter scope, e.g.,
//
// template<typename T>
// template<typename U>
// class A<T>::B { ... };
//
// We parse multiple levels non-recursively so that we can build a
// single data structure containing all of the template parameter
// lists to easily differentiate between the case above and:
//
// template<typename T>
// class A {
// template<typename U> class B;
// };
//
// In the first case, the action for declaring A<T>::B receives
// both template parameter lists. In the second case, the action for
// defining A<T>::B receives just the inner template parameter list
// (and retrieves the outer template parameter list from its
// context).
bool isSpecialization = true;
bool LastParamListWasEmpty = false;
TemplateParameterLists ParamLists;
TemplateParameterDepthRAII CurTemplateDepthTracker(TemplateParameterDepth);
do {
// Consume the 'export', if any.
SourceLocation ExportLoc;
TryConsumeToken(tok::kw_export, ExportLoc);
// Consume the 'template', which should be here.
SourceLocation TemplateLoc;
if (!TryConsumeToken(tok::kw_template, TemplateLoc)) {
Diag(Tok.getLocation(), diag::err_expected_template);
return nullptr;
}
// Parse the '<' template-parameter-list '>'
SourceLocation LAngleLoc, RAngleLoc;
SmallVector<NamedDecl*, 4> TemplateParams;
if (ParseTemplateParameters(TemplateParamScopes,
CurTemplateDepthTracker.getDepth(),
TemplateParams, LAngleLoc, RAngleLoc)) {
// Skip until the semi-colon or a '}'.
SkipUntil(tok::r_brace, StopAtSemi | StopBeforeMatch);
TryConsumeToken(tok::semi);
return nullptr;
}
ExprResult OptionalRequiresClauseConstraintER;
if (!TemplateParams.empty()) {
isSpecialization = false;
++CurTemplateDepthTracker;
if (TryConsumeToken(tok::kw_requires)) {
OptionalRequiresClauseConstraintER =
Actions.CorrectDelayedTyposInExpr(
ParseConstraintLogicalOrExpression(
/*IsTrailingRequiresClause=*/false));
if (!OptionalRequiresClauseConstraintER.isUsable()) {
// Skip until the semi-colon or a '}'.
SkipUntil(tok::r_brace, StopAtSemi | StopBeforeMatch);
TryConsumeToken(tok::semi);
return nullptr;
}
}
} else {
LastParamListWasEmpty = true;
}
ParamLists.push_back(Actions.ActOnTemplateParameterList(
CurTemplateDepthTracker.getDepth(), ExportLoc, TemplateLoc, LAngleLoc,
TemplateParams, RAngleLoc, OptionalRequiresClauseConstraintER.get()));
} while (Tok.isOneOf(tok::kw_export, tok::kw_template));
// Parse the actual template declaration.
if (Tok.is(tok::kw_concept))
return ParseConceptDefinition(
ParsedTemplateInfo(&ParamLists, isSpecialization,
LastParamListWasEmpty),
DeclEnd);
return ParseSingleDeclarationAfterTemplate(
Context,
ParsedTemplateInfo(&ParamLists, isSpecialization, LastParamListWasEmpty),
ParsingTemplateParams, DeclEnd, AccessAttrs, AS);
}
/// Parse a single declaration that declares a template,
/// template specialization, or explicit instantiation of a template.
///
/// \param DeclEnd will receive the source location of the last token
/// within this declaration.
///
/// \param AS the access specifier associated with this
/// declaration. Will be AS_none for namespace-scope declarations.
///
/// \returns the new declaration.
Decl *Parser::ParseSingleDeclarationAfterTemplate(
DeclaratorContext Context, const ParsedTemplateInfo &TemplateInfo,
ParsingDeclRAIIObject &DiagsFromTParams, SourceLocation &DeclEnd,
ParsedAttributes &AccessAttrs, AccessSpecifier AS) {
assert(TemplateInfo.Kind != ParsedTemplateInfo::NonTemplate &&
"Template information required");
if (Tok.is(tok::kw_static_assert)) {
// A static_assert declaration may not be templated.
Diag(Tok.getLocation(), diag::err_templated_invalid_declaration)
<< TemplateInfo.getSourceRange();
// Parse the static_assert declaration to improve error recovery.
return ParseStaticAssertDeclaration(DeclEnd);
}
if (Context == DeclaratorContext::MemberContext) {
// We are parsing a member template.
ParseCXXClassMemberDeclaration(AS, AccessAttrs, TemplateInfo,
&DiagsFromTParams);
return nullptr;
}
ParsedAttributesWithRange prefixAttrs(AttrFactory);
MaybeParseCXX11Attributes(prefixAttrs);
if (Tok.is(tok::kw_using)) {
auto usingDeclPtr = ParseUsingDirectiveOrDeclaration(Context, TemplateInfo, DeclEnd,
prefixAttrs);
if (!usingDeclPtr || !usingDeclPtr.get().isSingleDecl())
return nullptr;
return usingDeclPtr.get().getSingleDecl();
}
// Parse the declaration specifiers, stealing any diagnostics from
// the template parameters.
ParsingDeclSpec DS(*this, &DiagsFromTParams);
ParseDeclarationSpecifiers(DS, TemplateInfo, AS,
getDeclSpecContextFromDeclaratorContext(Context));
if (Tok.is(tok::semi)) {
ProhibitAttributes(prefixAttrs);
DeclEnd = ConsumeToken();
RecordDecl *AnonRecord = nullptr;
Decl *Decl = Actions.ParsedFreeStandingDeclSpec(
getCurScope(), AS, DS,
TemplateInfo.TemplateParams ? *TemplateInfo.TemplateParams
: MultiTemplateParamsArg(),
TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation,
AnonRecord);
assert(!AnonRecord &&
"Anonymous unions/structs should not be valid with template");
DS.complete(Decl);
return Decl;
}
// Move the attributes from the prefix into the DS.
if (TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation)
ProhibitAttributes(prefixAttrs);
else
DS.takeAttributesFrom(prefixAttrs);
// Parse the declarator.
ParsingDeclarator DeclaratorInfo(*this, DS, (DeclaratorContext)Context);
if (TemplateInfo.TemplateParams)
DeclaratorInfo.setTemplateParameterLists(*TemplateInfo.TemplateParams);
ParseDeclarator(DeclaratorInfo);
// Error parsing the declarator?
if (!DeclaratorInfo.hasName()) {
// If so, skip until the semi-colon or a }.
SkipUntil(tok::r_brace, StopAtSemi | StopBeforeMatch);
if (Tok.is(tok::semi))
ConsumeToken();
return nullptr;
}
llvm::TimeTraceScope TimeScope("ParseTemplate", [&]() {
return std::string(DeclaratorInfo.getIdentifier() != nullptr
? DeclaratorInfo.getIdentifier()->getName()
: "<unknown>");
});
LateParsedAttrList LateParsedAttrs(true);
if (DeclaratorInfo.isFunctionDeclarator()) {
if (Tok.is(tok::kw_requires))
ParseTrailingRequiresClause(DeclaratorInfo);
MaybeParseGNUAttributes(DeclaratorInfo, &LateParsedAttrs);
}
if (DeclaratorInfo.isFunctionDeclarator() &&
isStartOfFunctionDefinition(DeclaratorInfo)) {
// Function definitions are only allowed at file scope and in C++ classes.
// The C++ inline method definition case is handled elsewhere, so we only
// need to handle the file scope definition case.
if (Context != DeclaratorContext::FileContext) {
Diag(Tok, diag::err_function_definition_not_allowed);
SkipMalformedDecl();
return nullptr;
}
if (DS.getStorageClassSpec() == DeclSpec::SCS_typedef) {
// Recover by ignoring the 'typedef'. This was probably supposed to be
// the 'typename' keyword, which we should have already suggested adding
// if it's appropriate.
Diag(DS.getStorageClassSpecLoc(), diag::err_function_declared_typedef)
<< FixItHint::CreateRemoval(DS.getStorageClassSpecLoc());
DS.ClearStorageClassSpecs();
}
if (TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation) {
if (DeclaratorInfo.getName().getKind() !=
UnqualifiedIdKind::IK_TemplateId) {
// If the declarator-id is not a template-id, issue a diagnostic and
// recover by ignoring the 'template' keyword.
Diag(Tok, diag::err_template_defn_explicit_instantiation) << 0;
return ParseFunctionDefinition(DeclaratorInfo, ParsedTemplateInfo(),
&LateParsedAttrs);
} else {
SourceLocation LAngleLoc
= PP.getLocForEndOfToken(TemplateInfo.TemplateLoc);
Diag(DeclaratorInfo.getIdentifierLoc(),
diag::err_explicit_instantiation_with_definition)
<< SourceRange(TemplateInfo.TemplateLoc)
<< FixItHint::CreateInsertion(LAngleLoc, "<>");
// Recover as if it were an explicit specialization.
TemplateParameterLists FakedParamLists;
FakedParamLists.push_back(Actions.ActOnTemplateParameterList(
0, SourceLocation(), TemplateInfo.TemplateLoc, LAngleLoc, None,
LAngleLoc, nullptr));
return ParseFunctionDefinition(
DeclaratorInfo, ParsedTemplateInfo(&FakedParamLists,
/*isSpecialization=*/true,
/*lastParameterListWasEmpty=*/true),
&LateParsedAttrs);
}
}
return ParseFunctionDefinition(DeclaratorInfo, TemplateInfo,
&LateParsedAttrs);
}
// Parse this declaration.
Decl *ThisDecl = ParseDeclarationAfterDeclarator(DeclaratorInfo,
TemplateInfo);
if (Tok.is(tok::comma)) {
Diag(Tok, diag::err_multiple_template_declarators)
<< (int)TemplateInfo.Kind;
SkipUntil(tok::semi);
return ThisDecl;
}
// Eat the semi colon after the declaration.
ExpectAndConsumeSemi(diag::err_expected_semi_declaration);
if (LateParsedAttrs.size() > 0)
ParseLexedAttributeList(LateParsedAttrs, ThisDecl, true, false);
DeclaratorInfo.complete(ThisDecl);
return ThisDecl;
}
/// \brief Parse a single declaration that declares a concept.
///
/// \param DeclEnd will receive the source location of the last token
/// within this declaration.
///
/// \returns the new declaration.
Decl *
Parser::ParseConceptDefinition(const ParsedTemplateInfo &TemplateInfo,
SourceLocation &DeclEnd) {
assert(TemplateInfo.Kind != ParsedTemplateInfo::NonTemplate &&
"Template information required");
assert(Tok.is(tok::kw_concept) &&
"ParseConceptDefinition must be called when at a 'concept' keyword");
ConsumeToken(); // Consume 'concept'
SourceLocation BoolKWLoc;
if (TryConsumeToken(tok::kw_bool, BoolKWLoc))
Diag(Tok.getLocation(), diag::ext_concept_legacy_bool_keyword) <<
FixItHint::CreateRemoval(SourceLocation(BoolKWLoc));
DiagnoseAndSkipCXX11Attributes();
CXXScopeSpec SS;
if (ParseOptionalCXXScopeSpecifier(
SS, /*ObjectType=*/nullptr,
/*ObjectHadErrors=*/false, /*EnteringContext=*/false,
/*MayBePseudoDestructor=*/nullptr,
/*IsTypename=*/false, /*LastII=*/nullptr, /*OnlyNamespace=*/true) ||
SS.isInvalid()) {
SkipUntil(tok::semi);
return nullptr;
}
if (SS.isNotEmpty())
Diag(SS.getBeginLoc(),
diag::err_concept_definition_not_identifier);
UnqualifiedId Result;
if (ParseUnqualifiedId(SS, /*ObjectType=*/nullptr,
/*ObjectHadErrors=*/false, /*EnteringContext=*/false,
/*AllowDestructorName=*/false,
/*AllowConstructorName=*/false,
/*AllowDeductionGuide=*/false,
/*TemplateKWLoc=*/nullptr, Result)) {
SkipUntil(tok::semi);
return nullptr;
}
if (Result.getKind() != UnqualifiedIdKind::IK_Identifier) {
Diag(Result.getBeginLoc(), diag::err_concept_definition_not_identifier);
SkipUntil(tok::semi);
return nullptr;
}
IdentifierInfo *Id = Result.Identifier;
SourceLocation IdLoc = Result.getBeginLoc();
DiagnoseAndSkipCXX11Attributes();
if (!TryConsumeToken(tok::equal)) {
Diag(Tok.getLocation(), diag::err_expected) << tok::equal;
SkipUntil(tok::semi);
return nullptr;
}
ExprResult ConstraintExprResult =
Actions.CorrectDelayedTyposInExpr(ParseConstraintExpression());
if (ConstraintExprResult.isInvalid()) {
SkipUntil(tok::semi);
return nullptr;
}
DeclEnd = Tok.getLocation();
ExpectAndConsumeSemi(diag::err_expected_semi_declaration);
Expr *ConstraintExpr = ConstraintExprResult.get();
return Actions.ActOnConceptDefinition(getCurScope(),
*TemplateInfo.TemplateParams,
Id, IdLoc, ConstraintExpr);
}
/// ParseTemplateParameters - Parses a template-parameter-list enclosed in
/// angle brackets. Depth is the depth of this template-parameter-list, which
/// is the number of template headers directly enclosing this template header.
/// TemplateParams is the current list of template parameters we're building.
/// The template parameter we parse will be added to this list. LAngleLoc and
/// RAngleLoc will receive the positions of the '<' and '>', respectively,
/// that enclose this template parameter list.
///
/// \returns true if an error occurred, false otherwise.
bool Parser::ParseTemplateParameters(
MultiParseScope &TemplateScopes, unsigned Depth,
SmallVectorImpl<NamedDecl *> &TemplateParams, SourceLocation &LAngleLoc,
SourceLocation &RAngleLoc) {
// Get the template parameter list.
if (!TryConsumeToken(tok::less, LAngleLoc)) {
Diag(Tok.getLocation(), diag::err_expected_less_after) << "template";
return true;
}
// Try to parse the template parameter list.
bool Failed = false;
// FIXME: Missing greatergreatergreater support.
if (!Tok.is(tok::greater) && !Tok.is(tok::greatergreater)) {
TemplateScopes.Enter(Scope::TemplateParamScope);
Failed = ParseTemplateParameterList(Depth, TemplateParams);
}
if (Tok.is(tok::greatergreater)) {
// No diagnostic required here: a template-parameter-list can only be
// followed by a declaration or, for a template template parameter, the
// 'class' keyword. Therefore, the second '>' will be diagnosed later.
// This matters for elegant diagnosis of:
// template<template<typename>> struct S;
Tok.setKind(tok::greater);
RAngleLoc = Tok.getLocation();
Tok.setLocation(Tok.getLocation().getLocWithOffset(1));
} else if (!TryConsumeToken(tok::greater, RAngleLoc) && Failed) {
Diag(Tok.getLocation(), diag::err_expected) << tok::greater;
return true;
}
return false;
}
/// ParseTemplateParameterList - Parse a template parameter list. If
/// the parsing fails badly (i.e., closing bracket was left out), this
/// will try to put the token stream in a reasonable position (closing
/// a statement, etc.) and return false.
///
/// template-parameter-list: [C++ temp]
/// template-parameter
/// template-parameter-list ',' template-parameter
bool
Parser::ParseTemplateParameterList(const unsigned Depth,
SmallVectorImpl<NamedDecl*> &TemplateParams) {
while (1) {
if (NamedDecl *TmpParam
= ParseTemplateParameter(Depth, TemplateParams.size())) {
TemplateParams.push_back(TmpParam);
} else {
// If we failed to parse a template parameter, skip until we find
// a comma or closing brace.
SkipUntil(tok::comma, tok::greater, tok::greatergreater,
StopAtSemi | StopBeforeMatch);
}
// Did we find a comma or the end of the template parameter list?
if (Tok.is(tok::comma)) {
ConsumeToken();
} else if (Tok.isOneOf(tok::greater, tok::greatergreater)) {
// Don't consume this... that's done by template parser.
break;
} else {
// Somebody probably forgot to close the template. Skip ahead and
// try to get out of the expression. This error is currently
// subsumed by whatever goes on in ParseTemplateParameter.
Diag(Tok.getLocation(), diag::err_expected_comma_greater);
SkipUntil(tok::comma, tok::greater, tok::greatergreater,
StopAtSemi | StopBeforeMatch);
return false;
}
}
return true;
}
/// Determine whether the parser is at the start of a template
/// type parameter.
Parser::TPResult Parser::isStartOfTemplateTypeParameter() {
if (Tok.is(tok::kw_class)) {
// "class" may be the start of an elaborated-type-specifier or a
// type-parameter. Per C++ [temp.param]p3, we prefer the type-parameter.
switch (NextToken().getKind()) {
case tok::equal:
case tok::comma:
case tok::greater:
case tok::greatergreater:
case tok::ellipsis:
return TPResult::True;
case tok::identifier:
// This may be either a type-parameter or an elaborated-type-specifier.
// We have to look further.
break;
default:
return TPResult::False;
}
switch (GetLookAheadToken(2).getKind()) {
case tok::equal:
case tok::comma:
case tok::greater:
case tok::greatergreater:
return TPResult::True;
default:
return TPResult::False;
}
}
if (TryAnnotateTypeConstraint())
return TPResult::Error;
if (isTypeConstraintAnnotation() &&
// Next token might be 'auto' or 'decltype', indicating that this
// type-constraint is in fact part of a placeholder-type-specifier of a
// non-type template parameter.
!GetLookAheadToken(Tok.is(tok::annot_cxxscope) ? 2 : 1)
.isOneOf(tok::kw_auto, tok::kw_decltype))
return TPResult::True;
// 'typedef' is a reasonably-common typo/thinko for 'typename', and is
// ill-formed otherwise.
if (Tok.isNot(tok::kw_typename) && Tok.isNot(tok::kw_typedef))
return TPResult::False;
// C++ [temp.param]p2:
// There is no semantic difference between class and typename in a
// template-parameter. typename followed by an unqualified-id
// names a template type parameter. typename followed by a
// qualified-id denotes the type in a non-type
// parameter-declaration.
Token Next = NextToken();
// If we have an identifier, skip over it.
if (Next.getKind() == tok::identifier)
Next = GetLookAheadToken(2);
switch (Next.getKind()) {
case tok::equal:
case tok::comma:
case tok::greater:
case tok::greatergreater:
case tok::ellipsis:
return TPResult::True;
case tok::kw_typename:
case tok::kw_typedef:
case tok::kw_class:
// These indicate that a comma was missed after a type parameter, not that
// we have found a non-type parameter.
return TPResult::True;
default:
return TPResult::False;
}
}
/// ParseTemplateParameter - Parse a template-parameter (C++ [temp.param]).
///
/// template-parameter: [C++ temp.param]
/// type-parameter
/// parameter-declaration
///
/// type-parameter: (See below)
/// type-parameter-key ...[opt] identifier[opt]
/// type-parameter-key identifier[opt] = type-id
/// (C++2a) type-constraint ...[opt] identifier[opt]
/// (C++2a) type-constraint identifier[opt] = type-id
/// 'template' '<' template-parameter-list '>' type-parameter-key
/// ...[opt] identifier[opt]
/// 'template' '<' template-parameter-list '>' type-parameter-key
/// identifier[opt] '=' id-expression
///
/// type-parameter-key:
/// class
/// typename
///
NamedDecl *Parser::ParseTemplateParameter(unsigned Depth, unsigned Position) {
switch (isStartOfTemplateTypeParameter()) {
case TPResult::True:
// Is there just a typo in the input code? ('typedef' instead of
// 'typename')
if (Tok.is(tok::kw_typedef)) {
Diag(Tok.getLocation(), diag::err_expected_template_parameter);
Diag(Tok.getLocation(), diag::note_meant_to_use_typename)
<< FixItHint::CreateReplacement(CharSourceRange::getCharRange(
Tok.getLocation(),
Tok.getEndLoc()),
"typename");
Tok.setKind(tok::kw_typename);
}
return ParseTypeParameter(Depth, Position);
case TPResult::False:
break;
case TPResult::Error: {
// We return an invalid parameter as opposed to null to avoid having bogus
// diagnostics about an empty template parameter list.
// FIXME: Fix ParseTemplateParameterList to better handle nullptr results
// from here.
// Return a NTTP as if there was an error in a scope specifier, the user
// probably meant to write the type of a NTTP.
DeclSpec DS(getAttrFactory());
DS.SetTypeSpecError();
Declarator D(DS, DeclaratorContext::TemplateParamContext);
D.SetIdentifier(nullptr, Tok.getLocation());
D.setInvalidType(true);
NamedDecl *ErrorParam = Actions.ActOnNonTypeTemplateParameter(
getCurScope(), D, Depth, Position, /*EqualLoc=*/SourceLocation(),
/*DefaultArg=*/nullptr);
ErrorParam->setInvalidDecl(true);
SkipUntil(tok::comma, tok::greater, tok::greatergreater,
StopAtSemi | StopBeforeMatch);
return ErrorParam;
}
case TPResult::Ambiguous:
llvm_unreachable("template param classification can't be ambiguous");
}
if (Tok.is(tok::kw_template))
return ParseTemplateTemplateParameter(Depth, Position);
// If it's none of the above, then it must be a parameter declaration.
// NOTE: This will pick up errors in the closure of the template parameter
// list (e.g., template < ; Check here to implement >> style closures.
return ParseNonTypeTemplateParameter(Depth, Position);
}
/// Check whether the current token is a template-id annotation denoting a
/// type-constraint.
bool Parser::isTypeConstraintAnnotation() {
const Token &T = Tok.is(tok::annot_cxxscope) ? NextToken() : Tok;
if (T.isNot(tok::annot_template_id))
return false;
const auto *ExistingAnnot =
static_cast<TemplateIdAnnotation *>(T.getAnnotationValue());
return ExistingAnnot->Kind == TNK_Concept_template;
}
/// Try parsing a type-constraint at the current location.
///
/// type-constraint:
/// nested-name-specifier[opt] concept-name
/// nested-name-specifier[opt] concept-name
/// '<' template-argument-list[opt] '>'[opt]
///
/// \returns true if an error occurred, and false otherwise.
bool Parser::TryAnnotateTypeConstraint() {
if (!getLangOpts().CPlusPlus20)
return false;
CXXScopeSpec SS;
bool WasScopeAnnotation = Tok.is(tok::annot_cxxscope);
if (ParseOptionalCXXScopeSpecifier(SS, /*ObjectType=*/nullptr,
/*ObjectHadErrors=*/false,
/*EnteringContext=*/false,
/*MayBePseudoDestructor=*/nullptr,
// If this is not a type-constraint, then
// this scope-spec is part of the typename
// of a non-type template parameter
/*IsTypename=*/true, /*LastII=*/nullptr,
// We won't find concepts in
// non-namespaces anyway, so might as well
// parse this correctly for possible type
// names.
/*OnlyNamespace=*/false))
return true;
if (Tok.is(tok::identifier)) {
UnqualifiedId PossibleConceptName;
PossibleConceptName.setIdentifier(Tok.getIdentifierInfo(),
Tok.getLocation());
TemplateTy PossibleConcept;
bool MemberOfUnknownSpecialization = false;
auto TNK = Actions.isTemplateName(getCurScope(), SS,
/*hasTemplateKeyword=*/false,
PossibleConceptName,
/*ObjectType=*/ParsedType(),
/*EnteringContext=*/false,
PossibleConcept,
MemberOfUnknownSpecialization,
/*Disambiguation=*/true);
if (MemberOfUnknownSpecialization || !PossibleConcept ||
TNK != TNK_Concept_template) {
if (SS.isNotEmpty())
AnnotateScopeToken(SS, !WasScopeAnnotation);
return false;
}
// At this point we're sure we're dealing with a constrained parameter. It
// may or may not have a template parameter list following the concept
// name.
if (AnnotateTemplateIdToken(PossibleConcept, TNK, SS,
/*TemplateKWLoc=*/SourceLocation(),
PossibleConceptName,
/*AllowTypeAnnotation=*/false,
/*TypeConstraint=*/true))
return true;
}
if (SS.isNotEmpty())
AnnotateScopeToken(SS, !WasScopeAnnotation);
return false;
}
/// ParseTypeParameter - Parse a template type parameter (C++ [temp.param]).
/// Other kinds of template parameters are parsed in
/// ParseTemplateTemplateParameter and ParseNonTypeTemplateParameter.
///
/// type-parameter: [C++ temp.param]
/// 'class' ...[opt][C++0x] identifier[opt]
/// 'class' identifier[opt] '=' type-id
/// 'typename' ...[opt][C++0x] identifier[opt]
/// 'typename' identifier[opt] '=' type-id
NamedDecl *Parser::ParseTypeParameter(unsigned Depth, unsigned Position) {
assert((Tok.isOneOf(tok::kw_class, tok::kw_typename) ||
isTypeConstraintAnnotation()) &&
"A type-parameter starts with 'class', 'typename' or a "
"type-constraint");
CXXScopeSpec TypeConstraintSS;
TemplateIdAnnotation *TypeConstraint = nullptr;
bool TypenameKeyword = false;
SourceLocation KeyLoc;
ParseOptionalCXXScopeSpecifier(TypeConstraintSS, /*ObjectType=*/nullptr,
/*ObjectHadErrors=*/false,
/*EnteringContext*/ false);
if (Tok.is(tok::annot_template_id)) {
// Consume the 'type-constraint'.
TypeConstraint =
static_cast<TemplateIdAnnotation *>(Tok.getAnnotationValue());
assert(TypeConstraint->Kind == TNK_Concept_template &&
"stray non-concept template-id annotation");
KeyLoc = ConsumeAnnotationToken();
} else {
assert(TypeConstraintSS.isEmpty() &&
"expected type constraint after scope specifier");
// Consume the 'class' or 'typename' keyword.
TypenameKeyword = Tok.is(tok::kw_typename);
KeyLoc = ConsumeToken();
}
// Grab the ellipsis (if given).
SourceLocation EllipsisLoc;
if (TryConsumeToken(tok::ellipsis, EllipsisLoc)) {
Diag(EllipsisLoc,
getLangOpts().CPlusPlus11
? diag::warn_cxx98_compat_variadic_templates
: diag::ext_variadic_templates);
}
// Grab the template parameter name (if given)
SourceLocation NameLoc = Tok.getLocation();
IdentifierInfo *ParamName = nullptr;
if (Tok.is(tok::identifier)) {
ParamName = Tok.getIdentifierInfo();
ConsumeToken();
} else if (Tok.isOneOf(tok::equal, tok::comma, tok::greater,
tok::greatergreater)) {
// Unnamed template parameter. Don't have to do anything here, just
// don't consume this token.
} else {
Diag(Tok.getLocation(), diag::err_expected) << tok::identifier;
return nullptr;
}
// Recover from misplaced ellipsis.
bool AlreadyHasEllipsis = EllipsisLoc.isValid();
if (TryConsumeToken(tok::ellipsis, EllipsisLoc))
DiagnoseMisplacedEllipsis(EllipsisLoc, NameLoc, AlreadyHasEllipsis, true);
// Grab a default argument (if available).
// Per C++0x [basic.scope.pdecl]p9, we parse the default argument before
// we introduce the type parameter into the local scope.
SourceLocation EqualLoc;
ParsedType DefaultArg;
if (TryConsumeToken(tok::equal, EqualLoc))
DefaultArg = ParseTypeName(/*Range=*/nullptr,
DeclaratorContext::TemplateTypeArgContext)
.get();
NamedDecl *NewDecl = Actions.ActOnTypeParameter(getCurScope(),
TypenameKeyword, EllipsisLoc,
KeyLoc, ParamName, NameLoc,
Depth, Position, EqualLoc,
DefaultArg,
TypeConstraint != nullptr);
if (TypeConstraint) {
Actions.ActOnTypeConstraint(TypeConstraintSS, TypeConstraint,
cast<TemplateTypeParmDecl>(NewDecl),
EllipsisLoc);
}
return NewDecl;
}
/// ParseTemplateTemplateParameter - Handle the parsing of template
/// template parameters.
///
/// type-parameter: [C++ temp.param]
/// 'template' '<' template-parameter-list '>' type-parameter-key
/// ...[opt] identifier[opt]
/// 'template' '<' template-parameter-list '>' type-parameter-key
/// identifier[opt] = id-expression
/// type-parameter-key:
/// 'class'
/// 'typename' [C++1z]
NamedDecl *
Parser::ParseTemplateTemplateParameter(unsigned Depth, unsigned Position) {
assert(Tok.is(tok::kw_template) && "Expected 'template' keyword");
// Handle the template <...> part.
SourceLocation TemplateLoc = ConsumeToken();
SmallVector<NamedDecl*,8> TemplateParams;
SourceLocation LAngleLoc, RAngleLoc;
{
MultiParseScope TemplateParmScope(*this);
if (ParseTemplateParameters(TemplateParmScope, Depth + 1, TemplateParams,
LAngleLoc, RAngleLoc)) {
return nullptr;
}
}
// Provide an ExtWarn if the C++1z feature of using 'typename' here is used.
// Generate a meaningful error if the user forgot to put class before the
// identifier, comma, or greater. Provide a fixit if the identifier, comma,
// or greater appear immediately or after 'struct'. In the latter case,
// replace the keyword with 'class'.
if (!TryConsumeToken(tok::kw_class)) {
bool Replace = Tok.isOneOf(tok::kw_typename, tok::kw_struct);
const Token &Next = Tok.is(tok::kw_struct) ? NextToken() : Tok;
if (Tok.is(tok::kw_typename)) {
Diag(Tok.getLocation(),
getLangOpts().CPlusPlus17
? diag::warn_cxx14_compat_template_template_param_typename
: diag::ext_template_template_param_typename)
<< (!getLangOpts().CPlusPlus17
? FixItHint::CreateReplacement(Tok.getLocation(), "class")
: FixItHint());
} else if (Next.isOneOf(tok::identifier, tok::comma, tok::greater,
tok::greatergreater, tok::ellipsis)) {
Diag(Tok.getLocation(), diag::err_class_on_template_template_param)
<< (Replace ? FixItHint::CreateReplacement(Tok.getLocation(), "class")
: FixItHint::CreateInsertion(Tok.getLocation(), "class "));
} else
Diag(Tok.getLocation(), diag::err_class_on_template_template_param);
if (Replace)
ConsumeToken();
}
// Parse the ellipsis, if given.
SourceLocation EllipsisLoc;
if (TryConsumeToken(tok::ellipsis, EllipsisLoc))
Diag(EllipsisLoc,
getLangOpts().CPlusPlus11
? diag::warn_cxx98_compat_variadic_templates
: diag::ext_variadic_templates);
// Get the identifier, if given.
SourceLocation NameLoc = Tok.getLocation();
IdentifierInfo *ParamName = nullptr;
if (Tok.is(tok::identifier)) {
ParamName = Tok.getIdentifierInfo();
ConsumeToken();
} else if (Tok.isOneOf(tok::equal, tok::comma, tok::greater,
tok::greatergreater)) {
// Unnamed template parameter. Don't have to do anything here, just
// don't consume this token.
} else {
Diag(Tok.getLocation(), diag::err_expected) << tok::identifier;
return nullptr;
}
// Recover from misplaced ellipsis.
bool AlreadyHasEllipsis = EllipsisLoc.isValid();
if (TryConsumeToken(tok::ellipsis, EllipsisLoc))
DiagnoseMisplacedEllipsis(EllipsisLoc, NameLoc, AlreadyHasEllipsis, true);
TemplateParameterList *ParamList =
Actions.ActOnTemplateParameterList(Depth, SourceLocation(),
TemplateLoc, LAngleLoc,
TemplateParams,
RAngleLoc, nullptr);
// Grab a default argument (if available).
// Per C++0x [basic.scope.pdecl]p9, we parse the default argument before
// we introduce the template parameter into the local scope.
SourceLocation EqualLoc;
ParsedTemplateArgument DefaultArg;
if (TryConsumeToken(tok::equal, EqualLoc)) {
DefaultArg = ParseTemplateTemplateArgument();
if (DefaultArg.isInvalid()) {
Diag(Tok.getLocation(),
diag::err_default_template_template_parameter_not_template);
SkipUntil(tok::comma, tok::greater, tok::greatergreater,
StopAtSemi | StopBeforeMatch);
}
}
return Actions.ActOnTemplateTemplateParameter(getCurScope(), TemplateLoc,
ParamList, EllipsisLoc,
ParamName, NameLoc, Depth,
Position, EqualLoc, DefaultArg);
}
/// ParseNonTypeTemplateParameter - Handle the parsing of non-type
/// template parameters (e.g., in "template<int Size> class array;").
///
/// template-parameter:
/// ...
/// parameter-declaration
NamedDecl *
Parser::ParseNonTypeTemplateParameter(unsigned Depth, unsigned Position) {
// Parse the declaration-specifiers (i.e., the type).
// FIXME: The type should probably be restricted in some way... Not all
// declarators (parts of declarators?) are accepted for parameters.
DeclSpec DS(AttrFactory);
ParseDeclarationSpecifiers(DS, ParsedTemplateInfo(), AS_none,
DeclSpecContext::DSC_template_param);
// Parse this as a typename.
Declarator ParamDecl(DS, DeclaratorContext::TemplateParamContext);
ParseDeclarator(ParamDecl);
if (DS.getTypeSpecType() == DeclSpec::TST_unspecified) {
Diag(Tok.getLocation(), diag::err_expected_template_parameter);
return nullptr;
}
// Recover from misplaced ellipsis.
SourceLocation EllipsisLoc;
if (TryConsumeToken(tok::ellipsis, EllipsisLoc))
DiagnoseMisplacedEllipsisInDeclarator(EllipsisLoc, ParamDecl);
// If there is a default value, parse it.
// Per C++0x [basic.scope.pdecl]p9, we parse the default argument before
// we introduce the template parameter into the local scope.
SourceLocation EqualLoc;
ExprResult DefaultArg;
if (TryConsumeToken(tok::equal, EqualLoc)) {
// C++ [temp.param]p15:
// When parsing a default template-argument for a non-type
// template-parameter, the first non-nested > is taken as the
// end of the template-parameter-list rather than a greater-than
// operator.
GreaterThanIsOperatorScope G(GreaterThanIsOperator, false);
EnterExpressionEvaluationContext ConstantEvaluated(
Actions, Sema::ExpressionEvaluationContext::ConstantEvaluated);
DefaultArg = Actions.CorrectDelayedTyposInExpr(ParseAssignmentExpression());
if (DefaultArg.isInvalid())
SkipUntil(tok::comma, tok::greater, StopAtSemi | StopBeforeMatch);
}
// Create the parameter.
return Actions.ActOnNonTypeTemplateParameter(getCurScope(), ParamDecl,
Depth, Position, EqualLoc,
DefaultArg.get());
}
void Parser::DiagnoseMisplacedEllipsis(SourceLocation EllipsisLoc,
SourceLocation CorrectLoc,
bool AlreadyHasEllipsis,
bool IdentifierHasName) {
FixItHint Insertion;
if (!AlreadyHasEllipsis)
Insertion = FixItHint::CreateInsertion(CorrectLoc, "...");
Diag(EllipsisLoc, diag::err_misplaced_ellipsis_in_declaration)
<< FixItHint::CreateRemoval(EllipsisLoc) << Insertion
<< !IdentifierHasName;
}
void Parser::DiagnoseMisplacedEllipsisInDeclarator(SourceLocation EllipsisLoc,
Declarator &D) {
assert(EllipsisLoc.isValid());
bool AlreadyHasEllipsis = D.getEllipsisLoc().isValid();
if (!AlreadyHasEllipsis)
D.setEllipsisLoc(EllipsisLoc);
DiagnoseMisplacedEllipsis(EllipsisLoc, D.getIdentifierLoc(),
AlreadyHasEllipsis, D.hasName());
}
/// Parses a '>' at the end of a template list.
///
/// If this function encounters '>>', '>>>', '>=', or '>>=', it tries
/// to determine if these tokens were supposed to be a '>' followed by
/// '>', '>>', '>=', or '>='. It emits an appropriate diagnostic if necessary.
///
/// \param RAngleLoc the location of the consumed '>'.
///
/// \param ConsumeLastToken if true, the '>' is consumed.
///
/// \param ObjCGenericList if true, this is the '>' closing an Objective-C
/// type parameter or type argument list, rather than a C++ template parameter
/// or argument list.
///
/// \returns true, if current token does not start with '>', false otherwise.
bool Parser::ParseGreaterThanInTemplateList(SourceLocation LAngleLoc,
SourceLocation &RAngleLoc,
bool ConsumeLastToken,
bool ObjCGenericList) {
// What will be left once we've consumed the '>'.
tok::TokenKind RemainingToken;
const char *ReplacementStr = "> >";
bool MergeWithNextToken = false;
switch (Tok.getKind()) {
default:
Diag(getEndOfPreviousToken(), diag::err_expected) << tok::greater;
Diag(LAngleLoc, diag::note_matching) << tok::less;
return true;
case tok::greater:
// Determine the location of the '>' token. Only consume this token
// if the caller asked us to.
RAngleLoc = Tok.getLocation();
if (ConsumeLastToken)
ConsumeToken();
return false;
case tok::greatergreater:
RemainingToken = tok::greater;
break;
case tok::greatergreatergreater:
RemainingToken = tok::greatergreater;
break;
case tok::greaterequal:
RemainingToken = tok::equal;
ReplacementStr = "> =";
// Join two adjacent '=' tokens into one, for cases like:
// void (*p)() = f<int>;
// return f<int>==p;
if (NextToken().is(tok::equal) &&
areTokensAdjacent(Tok, NextToken())) {
RemainingToken = tok::equalequal;
MergeWithNextToken = true;
}
break;
case tok::greatergreaterequal:
RemainingToken = tok::greaterequal;
break;
}
// This template-id is terminated by a token that starts with a '>'.
// Outside C++11 and Objective-C, this is now error recovery.
//
// C++11 allows this when the token is '>>', and in CUDA + C++11 mode, we
// extend that treatment to also apply to the '>>>' token.
//
// Objective-C allows this in its type parameter / argument lists.
SourceLocation TokBeforeGreaterLoc = PrevTokLocation;
SourceLocation TokLoc = Tok.getLocation();
Token Next = NextToken();
// Whether splitting the current token after the '>' would undesirably result
// in the remaining token pasting with the token after it. This excludes the
// MergeWithNextToken cases, which we've already handled.
bool PreventMergeWithNextToken =
(RemainingToken == tok::greater ||
RemainingToken == tok::greatergreater) &&
(Next.isOneOf(tok::greater, tok::greatergreater,
tok::greatergreatergreater, tok::equal, tok::greaterequal,
tok::greatergreaterequal, tok::equalequal)) &&
areTokensAdjacent(Tok, Next);
// Diagnose this situation as appropriate.
if (!ObjCGenericList) {
// The source range of the replaced token(s).
CharSourceRange ReplacementRange = CharSourceRange::getCharRange(
TokLoc, Lexer::AdvanceToTokenCharacter(TokLoc, 2, PP.getSourceManager(),
getLangOpts()));
// A hint to put a space between the '>>'s. In order to make the hint as
// clear as possible, we include the characters either side of the space in
// the replacement, rather than just inserting a space at SecondCharLoc.
FixItHint Hint1 = FixItHint::CreateReplacement(ReplacementRange,
ReplacementStr);
// A hint to put another space after the token, if it would otherwise be
// lexed differently.
FixItHint Hint2;
if (PreventMergeWithNextToken)
Hint2 = FixItHint::CreateInsertion(Next.getLocation(), " ");
unsigned DiagId = diag::err_two_right_angle_brackets_need_space;
if (getLangOpts().CPlusPlus11 &&
(Tok.is(tok::greatergreater) || Tok.is(tok::greatergreatergreater)))
DiagId = diag::warn_cxx98_compat_two_right_angle_brackets;
else if (Tok.is(tok::greaterequal))
DiagId = diag::err_right_angle_bracket_equal_needs_space;
Diag(TokLoc, DiagId) << Hint1 << Hint2;
}
// Find the "length" of the resulting '>' token. This is not always 1, as it
// can contain escaped newlines.
unsigned GreaterLength = Lexer::getTokenPrefixLength(
TokLoc, 1, PP.getSourceManager(), getLangOpts());
// Annotate the source buffer to indicate that we split the token after the
// '>'. This allows us to properly find the end of, and extract the spelling
// of, the '>' token later.
RAngleLoc = PP.SplitToken(TokLoc, GreaterLength);
// Strip the initial '>' from the token.
bool CachingTokens = PP.IsPreviousCachedToken(Tok);
Token Greater = Tok;
Greater.setLocation(RAngleLoc);
Greater.setKind(tok::greater);
Greater.setLength(GreaterLength);
unsigned OldLength = Tok.getLength();
if (MergeWithNextToken) {
ConsumeToken();
OldLength += Tok.getLength();
}
Tok.setKind(RemainingToken);
Tok.setLength(OldLength - GreaterLength);
// Split the second token if lexing it normally would lex a different token
// (eg, the fifth token in 'A<B>>>' should re-lex as '>', not '>>').
SourceLocation AfterGreaterLoc = TokLoc.getLocWithOffset(GreaterLength);
if (PreventMergeWithNextToken)
AfterGreaterLoc = PP.SplitToken(AfterGreaterLoc, Tok.getLength());
Tok.setLocation(AfterGreaterLoc);
// Update the token cache to match what we just did if necessary.
if (CachingTokens) {
// If the previous cached token is being merged, delete it.
if (MergeWithNextToken)
PP.ReplacePreviousCachedToken({});
if (ConsumeLastToken)
PP.ReplacePreviousCachedToken({Greater, Tok});
else
PP.ReplacePreviousCachedToken({Greater});
}
if (ConsumeLastToken) {
PrevTokLocation = RAngleLoc;
} else {
PrevTokLocation = TokBeforeGreaterLoc;
PP.EnterToken(Tok, /*IsReinject=*/true);
Tok = Greater;
}
return false;
}
/// Parses a template-id that after the template name has
/// already been parsed.
///
/// This routine takes care of parsing the enclosed template argument
/// list ('<' template-parameter-list [opt] '>') and placing the
/// results into a form that can be transferred to semantic analysis.
///
/// \param ConsumeLastToken if true, then we will consume the last
/// token that forms the template-id. Otherwise, we will leave the
/// last token in the stream (e.g., so that it can be replaced with an
/// annotation token).
bool
Parser::ParseTemplateIdAfterTemplateName(bool ConsumeLastToken,
SourceLocation &LAngleLoc,
TemplateArgList &TemplateArgs,
SourceLocation &RAngleLoc) {
assert(Tok.is(tok::less) && "Must have already parsed the template-name");
// Consume the '<'.
LAngleLoc = ConsumeToken();
// Parse the optional template-argument-list.
bool Invalid = false;
{
GreaterThanIsOperatorScope G(GreaterThanIsOperator, false);
if (!Tok.isOneOf(tok::greater, tok::greatergreater,
tok::greatergreatergreater, tok::greaterequal,
tok::greatergreaterequal))
Invalid = ParseTemplateArgumentList(TemplateArgs);
if (Invalid) {
// Try to find the closing '>'.
if (getLangOpts().CPlusPlus11)
SkipUntil(tok::greater, tok::greatergreater,
tok::greatergreatergreater, StopAtSemi | StopBeforeMatch);
else
SkipUntil(tok::greater, StopAtSemi | StopBeforeMatch);
}
}
return ParseGreaterThanInTemplateList(LAngleLoc, RAngleLoc, ConsumeLastToken,
/*ObjCGenericList=*/false) ||
Invalid;
}
/// Replace the tokens that form a simple-template-id with an
/// annotation token containing the complete template-id.
///
/// The first token in the stream must be the name of a template that
/// is followed by a '<'. This routine will parse the complete
/// simple-template-id and replace the tokens with a single annotation
/// token with one of two different kinds: if the template-id names a
/// type (and \p AllowTypeAnnotation is true), the annotation token is
/// a type annotation that includes the optional nested-name-specifier
/// (\p SS). Otherwise, the annotation token is a template-id
/// annotation that does not include the optional
/// nested-name-specifier.
///
/// \param Template the declaration of the template named by the first
/// token (an identifier), as returned from \c Action::isTemplateName().
///
/// \param TNK the kind of template that \p Template
/// refers to, as returned from \c Action::isTemplateName().
///
/// \param SS if non-NULL, the nested-name-specifier that precedes
/// this template name.
///
/// \param TemplateKWLoc if valid, specifies that this template-id
/// annotation was preceded by the 'template' keyword and gives the
/// location of that keyword. If invalid (the default), then this
/// template-id was not preceded by a 'template' keyword.
///
/// \param AllowTypeAnnotation if true (the default), then a
/// simple-template-id that refers to a class template, template
/// template parameter, or other template that produces a type will be
/// replaced with a type annotation token. Otherwise, the
/// simple-template-id is always replaced with a template-id
/// annotation token.
///
/// \param TypeConstraint if true, then this is actually a type-constraint,
/// meaning that the template argument list can be omitted (and the template in
/// question must be a concept).
///
/// If an unrecoverable parse error occurs and no annotation token can be
/// formed, this function returns true.
///
bool Parser::AnnotateTemplateIdToken(TemplateTy Template, TemplateNameKind TNK,
CXXScopeSpec &SS,
SourceLocation TemplateKWLoc,
UnqualifiedId &TemplateName,
bool AllowTypeAnnotation,
bool TypeConstraint) {
assert(getLangOpts().CPlusPlus && "Can only annotate template-ids in C++");
assert((Tok.is(tok::less) || TypeConstraint) &&
"Parser isn't at the beginning of a template-id");
assert(!(TypeConstraint && AllowTypeAnnotation) && "type-constraint can't be "
"a type annotation");
assert((!TypeConstraint || TNK == TNK_Concept_template) && "type-constraint "
"must accompany a concept name");
assert((Template || TNK == TNK_Non_template) && "missing template name");
// Consume the template-name.
SourceLocation TemplateNameLoc = TemplateName.getSourceRange().getBegin();
// Parse the enclosed template argument list.
SourceLocation LAngleLoc, RAngleLoc;
TemplateArgList TemplateArgs;
bool ArgsInvalid = false;
if (!TypeConstraint || Tok.is(tok::less)) {
ArgsInvalid = ParseTemplateIdAfterTemplateName(false, LAngleLoc,
TemplateArgs, RAngleLoc);
// If we couldn't recover from invalid arguments, don't form an annotation
// token -- we don't know how much to annotate.
// FIXME: This can lead to duplicate diagnostics if we retry parsing this
// template-id in another context. Try to annotate anyway?
if (RAngleLoc.isInvalid())
return true;
}
ASTTemplateArgsPtr TemplateArgsPtr(TemplateArgs);
// Build the annotation token.
if (TNK == TNK_Type_template && AllowTypeAnnotation) {
TypeResult Type = ArgsInvalid
? TypeError()
: Actions.ActOnTemplateIdType(
getCurScope(), SS, TemplateKWLoc, Template,
TemplateName.Identifier, TemplateNameLoc,
LAngleLoc, TemplateArgsPtr, RAngleLoc);
Tok.setKind(tok::annot_typename);
setTypeAnnotation(Tok, Type);
if (SS.isNotEmpty())
Tok.setLocation(SS.getBeginLoc());
else if (TemplateKWLoc.isValid())
Tok.setLocation(TemplateKWLoc);
else
Tok.setLocation(TemplateNameLoc);
} else {
// Build a template-id annotation token that can be processed
// later.
Tok.setKind(tok::annot_template_id);
IdentifierInfo *TemplateII =
TemplateName.getKind() == UnqualifiedIdKind::IK_Identifier
? TemplateName.Identifier
: nullptr;
OverloadedOperatorKind OpKind =
TemplateName.getKind() == UnqualifiedIdKind::IK_Identifier
? OO_None
: TemplateName.OperatorFunctionId.Operator;
TemplateIdAnnotation *TemplateId = TemplateIdAnnotation::Create(
TemplateKWLoc, TemplateNameLoc, TemplateII, OpKind, Template, TNK,
LAngleLoc, RAngleLoc, TemplateArgs, ArgsInvalid, TemplateIds);
Tok.setAnnotationValue(TemplateId);
if (TemplateKWLoc.isValid())
Tok.setLocation(TemplateKWLoc);
else
Tok.setLocation(TemplateNameLoc);
}
// Common fields for the annotation token
Tok.setAnnotationEndLoc(RAngleLoc);
// In case the tokens were cached, have Preprocessor replace them with the
// annotation token.
PP.AnnotateCachedTokens(Tok);
return false;
}
/// Replaces a template-id annotation token with a type
/// annotation token.
///
/// If there was a failure when forming the type from the template-id,
/// a type annotation token will still be created, but will have a
/// NULL type pointer to signify an error.
///
/// \param SS The scope specifier appearing before the template-id, if any.
///
/// \param IsClassName Is this template-id appearing in a context where we
/// know it names a class, such as in an elaborated-type-specifier or
/// base-specifier? ('typename' and 'template' are unneeded and disallowed
/// in those contexts.)
void Parser::AnnotateTemplateIdTokenAsType(CXXScopeSpec &SS,
bool IsClassName) {
assert(Tok.is(tok::annot_template_id) && "Requires template-id tokens");
TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(Tok);
assert(TemplateId->mightBeType() &&
"Only works for type and dependent templates");
ASTTemplateArgsPtr TemplateArgsPtr(TemplateId->getTemplateArgs(),
TemplateId->NumArgs);
TypeResult Type =
TemplateId->isInvalid()
? TypeError()
: Actions.ActOnTemplateIdType(
getCurScope(), SS, TemplateId->TemplateKWLoc,
TemplateId->Template, TemplateId->Name,
TemplateId->TemplateNameLoc, TemplateId->LAngleLoc,
TemplateArgsPtr, TemplateId->RAngleLoc,
/*IsCtorOrDtorName*/ false, IsClassName);
// Create the new "type" annotation token.
Tok.setKind(tok::annot_typename);
setTypeAnnotation(Tok, Type);
if (SS.isNotEmpty()) // it was a C++ qualified type name.
Tok.setLocation(SS.getBeginLoc());
// End location stays the same
// Replace the template-id annotation token, and possible the scope-specifier
// that precedes it, with the typename annotation token.
PP.AnnotateCachedTokens(Tok);
}
/// Determine whether the given token can end a template argument.
static bool isEndOfTemplateArgument(Token Tok) {
// FIXME: Handle '>>>'.
return Tok.isOneOf(tok::comma, tok::greater, tok::greatergreater,
tok::greatergreatergreater);
}
/// Parse a C++ template template argument.
ParsedTemplateArgument Parser::ParseTemplateTemplateArgument() {
if (!Tok.is(tok::identifier) && !Tok.is(tok::coloncolon) &&
!Tok.is(tok::annot_cxxscope))
return ParsedTemplateArgument();
// C++0x [temp.arg.template]p1:
// A template-argument for a template template-parameter shall be the name
// of a class template or an alias template, expressed as id-expression.
//
// We parse an id-expression that refers to a class template or alias
// template. The grammar we parse is:
//
// nested-name-specifier[opt] template[opt] identifier ...[opt]
//
// followed by a token that terminates a template argument, such as ',',
// '>', or (in some cases) '>>'.
CXXScopeSpec SS; // nested-name-specifier, if present
ParseOptionalCXXScopeSpecifier(SS, /*ObjectType=*/nullptr,
/*ObjectHadErrors=*/false,
/*EnteringContext=*/false);
ParsedTemplateArgument Result;
SourceLocation EllipsisLoc;
if (SS.isSet() && Tok.is(tok::kw_template)) {
// Parse the optional 'template' keyword following the
// nested-name-specifier.
SourceLocation TemplateKWLoc = ConsumeToken();
if (Tok.is(tok::identifier)) {
// We appear to have a dependent template name.
UnqualifiedId Name;
Name.setIdentifier(Tok.getIdentifierInfo(), Tok.getLocation());
ConsumeToken(); // the identifier
TryConsumeToken(tok::ellipsis, EllipsisLoc);
// If the next token signals the end of a template argument, then we have
// a (possibly-dependent) template name that could be a template template
// argument.
TemplateTy Template;
if (isEndOfTemplateArgument(Tok) &&
Actions.ActOnTemplateName(getCurScope(), SS, TemplateKWLoc, Name,
/*ObjectType=*/nullptr,
/*EnteringContext=*/false, Template))
Result = ParsedTemplateArgument(SS, Template, Name.StartLocation);
}
} else if (Tok.is(tok::identifier)) {
// We may have a (non-dependent) template name.
TemplateTy Template;
UnqualifiedId Name;
Name.setIdentifier(Tok.getIdentifierInfo(), Tok.getLocation());
ConsumeToken(); // the identifier
TryConsumeToken(tok::ellipsis, EllipsisLoc);
if (isEndOfTemplateArgument(Tok)) {
bool MemberOfUnknownSpecialization;
TemplateNameKind TNK = Actions.isTemplateName(
getCurScope(), SS,
/*hasTemplateKeyword=*/false, Name,
/*ObjectType=*/nullptr,
/*EnteringContext=*/false, Template, MemberOfUnknownSpecialization);
if (TNK == TNK_Dependent_template_name || TNK == TNK_Type_template) {
// We have an id-expression that refers to a class template or
// (C++0x) alias template.
Result = ParsedTemplateArgument(SS, Template, Name.StartLocation);
}
}
}
// If this is a pack expansion, build it as such.
if (EllipsisLoc.isValid() && !Result.isInvalid())
Result = Actions.ActOnPackExpansion(Result, EllipsisLoc);
return Result;
}
/// ParseTemplateArgument - Parse a C++ template argument (C++ [temp.names]).
///
/// template-argument: [C++ 14.2]
/// constant-expression
/// type-id
/// id-expression
ParsedTemplateArgument Parser::ParseTemplateArgument() {
// C++ [temp.arg]p2:
// In a template-argument, an ambiguity between a type-id and an
// expression is resolved to a type-id, regardless of the form of
// the corresponding template-parameter.
//
// Therefore, we initially try to parse a type-id - and isCXXTypeId might look
// up and annotate an identifier as an id-expression during disambiguation,
// so enter the appropriate context for a constant expression template
// argument before trying to disambiguate.
EnterExpressionEvaluationContext EnterConstantEvaluated(
Actions, Sema::ExpressionEvaluationContext::ConstantEvaluated,
/*LambdaContextDecl=*/nullptr,
/*ExprContext=*/Sema::ExpressionEvaluationContextRecord::EK_TemplateArgument);
if (isCXXTypeId(TypeIdAsTemplateArgument)) {
TypeResult TypeArg = ParseTypeName(
/*Range=*/nullptr, DeclaratorContext::TemplateArgContext);
return Actions.ActOnTemplateTypeArgument(TypeArg);
}
// Try to parse a template template argument.
{
TentativeParsingAction TPA(*this);
ParsedTemplateArgument TemplateTemplateArgument
= ParseTemplateTemplateArgument();
if (!TemplateTemplateArgument.isInvalid()) {
TPA.Commit();
return TemplateTemplateArgument;
}
// Revert this tentative parse to parse a non-type template argument.
TPA.Revert();
}
// Parse a non-type template argument.
SourceLocation Loc = Tok.getLocation();
ExprResult ExprArg = ParseConstantExpressionInExprEvalContext(MaybeTypeCast);
if (ExprArg.isInvalid() || !ExprArg.get()) {
return ParsedTemplateArgument();
}
return ParsedTemplateArgument(ParsedTemplateArgument::NonType,
ExprArg.get(), Loc);
}
/// ParseTemplateArgumentList - Parse a C++ template-argument-list
/// (C++ [temp.names]). Returns true if there was an error.
///
/// template-argument-list: [C++ 14.2]
/// template-argument
/// template-argument-list ',' template-argument
bool
Parser::ParseTemplateArgumentList(TemplateArgList &TemplateArgs) {
ColonProtectionRAIIObject ColonProtection(*this, false);
do {
ParsedTemplateArgument Arg = ParseTemplateArgument();
SourceLocation EllipsisLoc;
if (TryConsumeToken(tok::ellipsis, EllipsisLoc))
Arg = Actions.ActOnPackExpansion(Arg, EllipsisLoc);
if (Arg.isInvalid())
return true;
// Save this template argument.
TemplateArgs.push_back(Arg);
// If the next token is a comma, consume it and keep reading
// arguments.
} while (TryConsumeToken(tok::comma));
return false;
}
/// Parse a C++ explicit template instantiation
/// (C++ [temp.explicit]).
///
/// explicit-instantiation:
/// 'extern' [opt] 'template' declaration
///
/// Note that the 'extern' is a GNU extension and C++11 feature.
Decl *Parser::ParseExplicitInstantiation(DeclaratorContext Context,
SourceLocation ExternLoc,
SourceLocation TemplateLoc,
SourceLocation &DeclEnd,
ParsedAttributes &AccessAttrs,
AccessSpecifier AS) {
// This isn't really required here.
ParsingDeclRAIIObject
ParsingTemplateParams(*this, ParsingDeclRAIIObject::NoParent);
return ParseSingleDeclarationAfterTemplate(
Context, ParsedTemplateInfo(ExternLoc, TemplateLoc),
ParsingTemplateParams, DeclEnd, AccessAttrs, AS);
}
SourceRange Parser::ParsedTemplateInfo::getSourceRange() const {
if (TemplateParams)
return getTemplateParamsRange(TemplateParams->data(),
TemplateParams->size());
SourceRange R(TemplateLoc);
if (ExternLoc.isValid())
R.setBegin(ExternLoc);
return R;
}
void Parser::LateTemplateParserCallback(void *P, LateParsedTemplate &LPT) {
((Parser *)P)->ParseLateTemplatedFuncDef(LPT);
}
/// Late parse a C++ function template in Microsoft mode.
void Parser::ParseLateTemplatedFuncDef(LateParsedTemplate &LPT) {
if (!LPT.D)
return;
// Destroy TemplateIdAnnotations when we're done, if possible.
DestroyTemplateIdAnnotationsRAIIObj CleanupRAII(*this);
// Get the FunctionDecl.
FunctionDecl *FunD = LPT.D->getAsFunction();
// Track template parameter depth.
TemplateParameterDepthRAII CurTemplateDepthTracker(TemplateParameterDepth);
// To restore the context after late parsing.
Sema::ContextRAII GlobalSavedContext(
Actions, Actions.Context.getTranslationUnitDecl());
MultiParseScope Scopes(*this);
// Get the list of DeclContexts to reenter.
SmallVector<DeclContext*, 4> DeclContextsToReenter;
for (DeclContext *DC = FunD; DC && !DC->isTranslationUnit();
DC = DC->getLexicalParent())
DeclContextsToReenter.push_back(DC);
// Reenter scopes from outermost to innermost.
for (DeclContext *DC : reverse(DeclContextsToReenter)) {
CurTemplateDepthTracker.addDepth(
ReenterTemplateScopes(Scopes, cast<Decl>(DC)));
Scopes.Enter(Scope::DeclScope);
// We'll reenter the function context itself below.
if (DC != FunD)
Actions.PushDeclContext(Actions.getCurScope(), DC);
}
assert(!LPT.Toks.empty() && "Empty body!");
// Append the current token at the end of the new token stream so that it
// doesn't get lost.
LPT.Toks.push_back(Tok);
PP.EnterTokenStream(LPT.Toks, true, /*IsReinject*/true);
// Consume the previously pushed token.
ConsumeAnyToken(/*ConsumeCodeCompletionTok=*/true);
assert(Tok.isOneOf(tok::l_brace, tok::colon, tok::kw_try) &&
"Inline method not starting with '{', ':' or 'try'");
// Parse the method body. Function body parsing code is similar enough
// to be re-used for method bodies as well.
ParseScope FnScope(this, Scope::FnScope | Scope::DeclScope |
Scope::CompoundStmtScope);
// Recreate the containing function DeclContext.
Sema::ContextRAII FunctionSavedContext(Actions, FunD->getLexicalParent());
Actions.ActOnStartOfFunctionDef(getCurScope(), FunD);
if (Tok.is(tok::kw_try)) {
ParseFunctionTryBlock(LPT.D, FnScope);
} else {
if (Tok.is(tok::colon))
ParseConstructorInitializer(LPT.D);
else
Actions.ActOnDefaultCtorInitializers(LPT.D);
if (Tok.is(tok::l_brace)) {
assert((!isa<FunctionTemplateDecl>(LPT.D) ||
cast<FunctionTemplateDecl>(LPT.D)
->getTemplateParameters()
->getDepth() == TemplateParameterDepth - 1) &&
"TemplateParameterDepth should be greater than the depth of "
"current template being instantiated!");
ParseFunctionStatementBody(LPT.D, FnScope);
Actions.UnmarkAsLateParsedTemplate(FunD);
} else
Actions.ActOnFinishFunctionBody(LPT.D, nullptr);
}
}
/// Lex a delayed template function for late parsing.
void Parser::LexTemplateFunctionForLateParsing(CachedTokens &Toks) {
tok::TokenKind kind = Tok.getKind();
if (!ConsumeAndStoreFunctionPrologue(Toks)) {
// Consume everything up to (and including) the matching right brace.
ConsumeAndStoreUntil(tok::r_brace, Toks, /*StopAtSemi=*/false);
}
// If we're in a function-try-block, we need to store all the catch blocks.
if (kind == tok::kw_try) {
while (Tok.is(tok::kw_catch)) {
ConsumeAndStoreUntil(tok::l_brace, Toks, /*StopAtSemi=*/false);
ConsumeAndStoreUntil(tok::r_brace, Toks, /*StopAtSemi=*/false);
}
}
}
/// We've parsed something that could plausibly be intended to be a template
/// name (\p LHS) followed by a '<' token, and the following code can't possibly
/// be an expression. Determine if this is likely to be a template-id and if so,
/// diagnose it.
bool Parser::diagnoseUnknownTemplateId(ExprResult LHS, SourceLocation Less) {
TentativeParsingAction TPA(*this);
// FIXME: We could look at the token sequence in a lot more detail here.
if (SkipUntil(tok::greater, tok::greatergreater, tok::greatergreatergreater,
StopAtSemi | StopBeforeMatch)) {
TPA.Commit();
SourceLocation Greater;
ParseGreaterThanInTemplateList(Less, Greater, true, false);
Actions.diagnoseExprIntendedAsTemplateName(getCurScope(), LHS,
Less, Greater);
return true;
}
// There's no matching '>' token, this probably isn't supposed to be
// interpreted as a template-id. Parse it as an (ill-formed) comparison.
TPA.Revert();
return false;
}
void Parser::checkPotentialAngleBracket(ExprResult &PotentialTemplateName) {
assert(Tok.is(tok::less) && "not at a potential angle bracket");
bool DependentTemplateName = false;
if (!Actions.mightBeIntendedToBeTemplateName(PotentialTemplateName,
DependentTemplateName))
return;
// OK, this might be a name that the user intended to be parsed as a
// template-name, followed by a '<' token. Check for some easy cases.
// If we have potential_template<>, then it's supposed to be a template-name.
if (NextToken().is(tok::greater) ||
(getLangOpts().CPlusPlus11 &&
NextToken().isOneOf(tok::greatergreater, tok::greatergreatergreater))) {
SourceLocation Less = ConsumeToken();
SourceLocation Greater;
ParseGreaterThanInTemplateList(Less, Greater, true, false);
Actions.diagnoseExprIntendedAsTemplateName(
getCurScope(), PotentialTemplateName, Less, Greater);
// FIXME: Perform error recovery.
PotentialTemplateName = ExprError();
return;
}
// If we have 'potential_template<type-id', assume it's supposed to be a
// template-name if there's a matching '>' later on.
{
// FIXME: Avoid the tentative parse when NextToken() can't begin a type.
TentativeParsingAction TPA(*this);
SourceLocation Less = ConsumeToken();
if (isTypeIdUnambiguously() &&
diagnoseUnknownTemplateId(PotentialTemplateName, Less)) {
TPA.Commit();
// FIXME: Perform error recovery.
PotentialTemplateName = ExprError();
return;
}
TPA.Revert();
}
// Otherwise, remember that we saw this in case we see a potentially-matching
// '>' token later on.
AngleBracketTracker::Priority Priority =
(DependentTemplateName ? AngleBracketTracker::DependentName
: AngleBracketTracker::PotentialTypo) |
(Tok.hasLeadingSpace() ? AngleBracketTracker::SpaceBeforeLess
: AngleBracketTracker::NoSpaceBeforeLess);
AngleBrackets.add(*this, PotentialTemplateName.get(), Tok.getLocation(),
Priority);
}
bool Parser::checkPotentialAngleBracketDelimiter(
const AngleBracketTracker::Loc &LAngle, const Token &OpToken) {
// If a comma in an expression context is followed by a type that can be a
// template argument and cannot be an expression, then this is ill-formed,
// but might be intended to be part of a template-id.
if (OpToken.is(tok::comma) && isTypeIdUnambiguously() &&
diagnoseUnknownTemplateId(LAngle.TemplateName, LAngle.LessLoc)) {
AngleBrackets.clear(*this);
return true;
}
// If a context that looks like a template-id is followed by '()', then
// this is ill-formed, but might be intended to be a template-id
// followed by '()'.
if (OpToken.is(tok::greater) && Tok.is(tok::l_paren) &&
NextToken().is(tok::r_paren)) {
Actions.diagnoseExprIntendedAsTemplateName(
getCurScope(), LAngle.TemplateName, LAngle.LessLoc,
OpToken.getLocation());
AngleBrackets.clear(*this);
return true;
}
// After a '>' (etc), we're no longer potentially in a construct that's
// intended to be treated as a template-id.
if (OpToken.is(tok::greater) ||
(getLangOpts().CPlusPlus11 &&
OpToken.isOneOf(tok::greatergreater, tok::greatergreatergreater)))
AngleBrackets.clear(*this);
return false;
}
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