================
@@ -55,14 +75,204 @@ static bool HasDependentSize(const CXXExpansionStmtPattern
*Pattern) {
}
case CXXExpansionStmtPattern::ExpansionStmtKind::Iterating:
- case CXXExpansionStmtPattern::ExpansionStmtKind::Destructuring:
+ // Even if the size isn't technically dependent, delay expansion until
+ // we're no longer in a template since evaluating a lambda declared in
+ // a template doesn't work too well.
+ assert(CurContext->isExpansionStmt());
+ return CurContext->getParent()->isDependentContext();
+
case CXXExpansionStmtPattern::ExpansionStmtKind::Dependent:
+ return true;
+
+ case CXXExpansionStmtPattern::ExpansionStmtKind::Destructuring:
llvm_unreachable("TODO");
}
llvm_unreachable("invalid pattern kind");
}
+static IterableExpansionStmtData TryBuildIterableExpansionStmtInitializer(
+ Sema &S, Expr *ExpansionInitializer, Expr *Index, SourceLocation ColonLoc,
+ bool VarIsConstexpr,
+ ArrayRef<MaterializeTemporaryExpr *> LifetimeExtendTemps) {
+ IterableExpansionStmtData Data;
+
+ // C++26 [stmt.expand]p3: An expression is expansion-iterable if it does not
+ // have array type [...]
+ QualType Ty = ExpansionInitializer->getType().getNonReferenceType();
+ if (Ty->isArrayType())
+ return Data;
+
+ // Lookup member and ADL 'begin()'/'end()'. Only check if they exist; even if
+ // they're deleted, inaccessible, etc., this is still an iterating expansion
+ // statement, albeit an ill-formed one.
+ DeclarationNameInfo BeginName(&S.PP.getIdentifierTable().get("begin"),
+ ColonLoc);
+ DeclarationNameInfo EndName(&S.PP.getIdentifierTable().get("end"), ColonLoc);
+
+ // Try member lookup first.
+ bool FoundBeginEnd = false;
+ if (auto *Record = Ty->getAsCXXRecordDecl()) {
+ LookupResult BeginLR(S, BeginName, Sema::LookupMemberName);
+ LookupResult EndLR(S, EndName, Sema::LookupMemberName);
+ FoundBeginEnd = S.LookupQualifiedName(BeginLR, Record) &&
+ S.LookupQualifiedName(EndLR, Record);
+ }
+
+ // Try ADL.
+ //
+ // If overload resolution for 'begin()' *and* 'end()' succeeds (irrespective
+ // of whether it results in a usable candidate), then assume this is an
+ // iterating expansion statement.
+ auto HasADLCandidate = [&](DeclarationName Name) {
+ OverloadCandidateSet Candidates(ColonLoc,
OverloadCandidateSet::CSK_Normal);
+ OverloadCandidateSet::iterator Best;
+
+ S.AddArgumentDependentLookupCandidates(Name, ColonLoc,
ExpansionInitializer,
+ /*ExplicitTemplateArgs=*/nullptr,
+ Candidates);
+
+ return Candidates.BestViableFunction(S, ColonLoc, Best) !=
+ OR_No_Viable_Function;
+ };
+
+ if (!FoundBeginEnd && (!HasADLCandidate(BeginName.getName()) ||
+ !HasADLCandidate(EndName.getName())))
+ return Data;
+
+ auto Ctx = Sema::ExpressionEvaluationContext::PotentiallyEvaluated;
+ if (VarIsConstexpr)
+ Ctx = Sema::ExpressionEvaluationContext::ImmediateFunctionContext;
----------------
Sirraide wrote:
See
- https://github.com/llvm/llvm-project/pull/169681#discussion_r3182730176
- https://github.com/llvm/llvm-project/pull/169682#discussion_r3182774060
tl;dr that helper was meant only for `Parser::ParseForStatement()`
https://github.com/llvm/llvm-project/pull/169684
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