[PATCH] D26750: [clang-tidy] Add modernize-use-default-member-init check

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman added inline comments.


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Comment at: clang-tidy/modernize/UseDefaultMemberInitCheck.cpp:34
+  case Type::STK_IntegralComplex:
+    return InitType->isCharType() ? "'\\0'" : "0";
+  case Type::STK_Floating:
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malcolm.parsons wrote:
> aaron.ballman wrote:
> > This is incorrect if the char type is not a narrow character type. I would probably just initialize the integral with `0`, regardless of whether it was a character or not. You should add a test for char, wchar_t, char16_t (et al), and probably all of the other types (just to make sure we handle them properly and don't introduce later regressions).
> `isCharType()` returns true for narrow character types only.
> So if this is incorrect, wouldn't your suggestion be incorrect too?
Ah, I think I made a confusing statement. By "incorrect", I meant, "inconsistent." For int, you would get 0, for char, you would get '\0', but for wchar_t you would get 0 instead of L'\0', for char16_t you would get 0 instead of u'\0', etc. Rather than deal with all of the prefixing, I think it's better to just initialize with 0 for all integral types.


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Comment at: clang-tidy/modernize/UseDefaultMemberInitCheck.cpp:112
+  }
+}
+
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malcolm.parsons wrote:
> aaron.ballman wrote:
> > You'll need to add the `llvm_unreachable()` here in order to avoid MSVC warnings about not all control paths returning a value.
> AFAIK, that's when a switch covers all valid enum values but doesn't have a default case.
> This switch has a default case.
Yes, but MSVC often doesn't pick up on that fact. We've used this pattern in the past (see `getAbsoluteValueFunctionKind()` in SemaChecking.cpp), but perhaps this is fine and we can deal with any diagnostics post-commit (I didn't check whether the warning really happens, I was going from memory).


https://reviews.llvm.org/D26750