[PATCH] D143466: [clang][Interp] Fix initializing base class members

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman added inline comments.


================
Comment at: clang/test/AST/Interp/records.cpp:260
+  class _C : public _B {};
+  constexpr _C c{12};
+};
----------------
We should test that the initialization actually happened.


================
Comment at: clang/test/AST/Interp/records.cpp:262
+};
+#endif
+
----------------
Another test would be for invalid base initialization, like:
```
struct Base {
  int a;
};

struct Intermediate : Base {
  int b;
};

struct Final : Intermediate {
  int c;

  constexpr Final(int a, int b, int c) : c(c) {}
};

static_assert(Final{1, 2, 3}.c == 3, ""); // OK
static_assert(Final{1, 2, 3}.a == 0, ""); // Error, reads uninitialized member
```
or with multiple bases:
```
struct Base {
  int a;
};

struct Mixin  {
  int b;

  constexpr Mixin() = default;
  constexpr Mixin(int b) : b(b) {}
};

struct Final : Base, Mixin {
  int c;

  constexpr Final(int a, int b, int c) : Mixin(b), c(c) {}
  constexpr Final(int a, int b, int c, bool) : c(c) {}
};

static_assert(Final{1, 2, 3}.c == 3, ""); // OK
static_assert(Final{1, 2, 3}.b == 2, ""); // OK
static_assert(Final{1, 2, 3}.a == 0, ""); // Error, reads uninitialized member
```
or in a different form:
```
struct Base {
  int a;
};

struct Mixin  {
  int b;
};

struct Final : Base, Mixin {
  int c;

  constexpr Final(int a, int b, int c) : c(c) { this->b = b; }
  constexpr Final(int a, int b, int c, bool) : c(c) {}
};

static_assert(Final{1, 2, 3}.c == 3, ""); // OK
static_assert(Final{1, 2, 3}.b == 2, ""); // OK
static_assert(Final{1, 2, 3}.a == 0, ""); // Error, reads uninitialized member
```


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D143466/new/

https://reviews.llvm.org/D143466