[Clang] Handle sema of noexcept condition in their evaluation context. (#67538)

The conditions of a noexcept and explicit specifier are full
expressions. Before this patch, we would call ActOnFinishFullExpr on
these in the context of the enclosing expression, which would cause the
collect of odr-used variables (and subsequently capture attempts) in the
wrong (enclosing) context.

This was observable when parsing the noexcept specifier condition of a
lambda appearing in a wider full expression odr-using variables.

Fixes #67492

1 files changed, 5 insertions, 1 deletions

diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index 748b9d5..9bda4ec 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -4120,7 +4120,11 @@ void Parser::ParseDeclarationSpecifiers(
           ExprResult ExplicitExpr(static_cast<Expr *>(nullptr));
           BalancedDelimiterTracker Tracker(*this, tok::l_paren);
           Tracker.consumeOpen();
-          ExplicitExpr = ParseConstantExpression();
+
+          EnterExpressionEvaluationContext ConstantEvaluated(
+              Actions, Sema::ExpressionEvaluationContext::ConstantEvaluated);
+
+          ExplicitExpr = ParseConstantExpressionInExprEvalContext();
           ConsumedEnd = Tok.getLocation();
           if (ExplicitExpr.isUsable()) {
             CloseParenLoc = Tok.getLocation();