================
@@ -5567,19 +5568,35 @@ ExprResult Sema::BuildCXXDefaultInitExpr(SourceLocation
Loc, FieldDecl *Field) {
ImmediateCallVisitor V(getASTContext());
if (!NestedDefaultChecking)
V.TraverseDecl(Field);
- if (V.HasImmediateCalls) {
+
+ // CWG1815
+ // Support lifetime extension of temporary created by aggregate
+ // initialization using a default member initializer. We should always
rebuild
+ // the initializer if it contains any temporaries (if the initializer
+ // expression is an ExprWithCleanups). Then make sure the normal lifetime
+ // extension code recurses into the default initializer and does lifetime
+ // extension when warranted.
+ bool ContainsAnyTemporaries =
+ isa_and_present<ExprWithCleanups>(Field->getInClassInitializer());
+ if (V.HasImmediateCalls || InLifetimeExtendingContext ||
+ ContainsAnyTemporaries) {
ExprEvalContexts.back().DelayedDefaultInitializationContext = {Loc, Field,
CurContext};
ExprEvalContexts.back().IsCurrentlyCheckingDefaultArgumentOrInitializer =
NestedDefaultChecking;
-
+ // Pass down lifetime extending flag, and collect temporaries in
+ // CreateMaterializeTemporaryExpr when we rewrite the call argument.
+ keepInLifetimeExtendingContext();
EnsureImmediateInvocationInDefaultArgs Immediate(*this);
ExprResult Res;
+
+ // Rebuild CXXDefaultInitExpr might cause diagnostics.
+ SFINAETrap Trap(*this);
----------------
yronglin wrote:
This was used to silence the duplocated access diagnostics:
```C++
class Private {
Private(int);
public:
Private();
};
class S {
Private p = 42;
S() {}
S(int) {}
};
S s{};
```
The latest clang trunk will emit 2 erros https://godbolt.org/z/dWcqY97GK, and
without this, this PR will emit duplicated errors:
```
./access.cpp:8:15: error: field of type 'Private' has private constructor
8 | Private p = 42;
| ^
./access.cpp:2:3: note: implicitly declared private here
2 | Private(int);
| ^
Contains Error: 0
./access.cpp:8:15: error: field of type 'Private' has private constructor
8 | Private p = 42;
| ^
./access.cpp:2:3: note: implicitly declared private here
2 | Private(int);
| ^
Contains Error: 0
./access.cpp:8:15: error: field of type 'Private' has private constructor
8 | Private p = 42;
| ^
./access.cpp:2:3: note: implicitly declared private here
2 | Private(int);
| ^
./access.cpp:13:3: error: calling a private constructor of class 'S'
13 | S s{};
| ^
./access.cpp:9:3: note: implicitly declared private here
9 | S() {}
| ^
4 errors generated.
```
This doesn't seem like a good approach. If the in-class-initializer contains
error(or warnings?), should we skip rebuild the init expr? And seems
Expr::containsErrors doesn't works for accessibility issues.
https://github.com/llvm/llvm-project/pull/97308
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