MismatchingNewDeleteDetector uses incorrect field, and finds no initializer

[ismailp]

Summary

In MismatchingNewDeleteDetector::analyzeInClassInitializer, if
Field's initializer expression is null, lookup the field in
implicit instantiation, and use found field's the initializer.

[rsmith]

lib/Sema/SemaExprCXX.cpp

2494 ↗

(On Diff #26189)

You'll still crash if this check fails. You could assert this condition instead, but InitExpr could still be null even then, in principle (if we're somehow getting called while still parsing the definition of the class).

The in-class initializer is not relevant if no constructor actually uses it. Instead of this change, you could just return EndOfTU ? NoMismatch : AnalyzeLater if InitExpr is null.

[ismailp]

Return from analyzeInClassInitializer, if in-class initializer is null.

[ismailp]

Ping.

[ismailp]

Ping! It seems like this patch was forgotten. This fixes PR24730, which is reported recently.

[ismailp]

Ping!

[rsmith]

LGTM

cfe/trunk/lib/Sema/SemaExprCXX.cpp

if (hasMatchingNewInCtorInit(CI))
       return true;
   }
   return false;
 }
 
 MismatchingNewDeleteDetector::MismatchResult
 MismatchingNewDeleteDetector::analyzeInClassInitializer() {
   assert(Field != nullptr && "This should be called only for members");
-  if (const CXXNewExpr *NE =
-          getNewExprFromInitListOrExpr(Field->getInClassInitializer())) {
+  const Expr *InitExpr = Field->getInClassInitializer();
+  if (!InitExpr)
+    return EndOfTU ? NoMismatch : AnalyzeLater;
+  if (const CXXNewExpr *NE = getNewExprFromInitListOrExpr(InitExpr)) {
     if (NE->isArray() != IsArrayForm) {
       NewExprs.push_back(NE);
       return MemberInitMismatches;
     }
   }
   return NoMismatch;
 }
 

cfe/trunk/test/SemaCXX/delete.cpp

void f() {
   delete  [    ] c;   // expected-warning {{'delete[]' applied to a pointer that was allocated with 'new'; did you mean 'delete'?}}
   // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:17}:""
   delete d;           // expected-warning {{'delete' applied to a pointer that was allocated with 'new[]'; did you mean 'delete[]'?}}
   // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:9}:"[]"
   DELETE_ARRAY(a);    // expected-warning {{'delete[]' applied to a pointer that was allocated with 'new'; did you mean 'delete'?}}
   DELETE(d);          // expected-warning {{'delete' applied to a pointer that was allocated with 'new[]'; did you mean 'delete[]'?}}
 }
 }
+
+namespace MissingInitializer {
+template<typename T>
+struct Base {
+  struct S {
+    const T *p1 = nullptr;
+    const T *p2 = new T[3];
+  };
+};
+
+void null_init(Base<double>::S s) {
+  delete s.p1;
+  delete s.p2;
+}
+}
+
 #ifndef WITH_PCH
 pch_test::X::X()
   : a(new int[1])  // expected-note{{allocated with 'new[]' here}}
 { }
 pch_test::X::X(int i)
   : a(new int[i])  // expected-note{{allocated with 'new[]' here}}
 { }
 #endif