[PATCH] D150411: [NFC][Clang][Coverity] Fix Static Code Analysis Concerns with copy without assign

[Tom Honermann via Phabricator via cfe-commits]

tahonermann requested changes to this revision.
tahonermann added a comment.
This revision now requires changes to proceed.

I added a few comments and suggested edits, but this is mostly looking good.



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Comment at: clang/include/clang/Sema/Sema.h:1790
     SemaDiagnosticBuilder(const SemaDiagnosticBuilder &) = default;
+    SemaDiagnosticBuilder &operator=(const SemaDiagnosticBuilder &) = delete;
     ~SemaDiagnosticBuilder();
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Comment at: clang/include/clang/Sema/Sema.h:1789-1791
+    SemaDiagnosticBuilder &operator=(SemaDiagnosticBuilder &&D) = delete;
     SemaDiagnosticBuilder(const SemaDiagnosticBuilder &) = default;
+    SemaDiagnosticBuilder &operator=(const SemaDiagnosticBuilder &) = delete;
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aaronpuchert wrote:
> Manna wrote:
> > @tahonermann This is follow-up comments from https://reviews.llvm.org/D149718?id=519331#inline-1452044. 
> > 
> > >>This change still declares a move assignment operator, but doesn't provide a definition. The move constructor is implemented in clang/lib/Sema/Sema.cpp, so I would expect to see the move assignment operator definition provided there as well.
> > 
> > I tried to define move assignment operator in ` clang/lib/Sema/Sema.cpp` but it failed because class Sema has deleted implicit copy assignment operator.
> > 
> > ```
> > /// Sema - This implements semantic analysis and AST building for C.
> > class Sema final {
> >   Sema(const Sema &) = delete;
> >   void operator=(const Sema &) = delete;
> > ```
> > It seems like support for assignment is not desired, We probably need deleted copy/move assignment operator.
> > 
> These are also implicitly deleted. Some code styles want this explicitly spelled out, but I don't think ours does.
> I tried to define move assignment operator in  clang/lib/Sema/Sema.cpp but it failed because class Sema has deleted implicit copy assignment operator.

It is still permissible to define a move assignment operator if the implicit copy assignment operator is deleted. See https://godbolt.org/z/sGaWd9M44.

I think it is fine to disable support for assignment for this class pending use cases. But, since a move constructor is explicitly defined, we should also be explicit above move assignment. I added a suggested edit. Without that change, I think Coverity will continue to complain.


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Comment at: clang/include/clang/StaticAnalyzer/Core/BugReporter/BugReporterVisitors.h:54
   BugReporterVisitor(BugReporterVisitor &&) {}
+  BugReporterVisitor &operator=(const BugReporterVisitor &) = delete;
   virtual ~BugReporterVisitor();
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Here too; since a user-defined move constructor is declared, let's be explicit about move assignment.


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Comment at: clang/lib/CodeGen/CGDebugInfo.h:833-837
+  ApplyDebugLocation &operator=(ApplyDebugLocation &&Other) {
+    CGF = Other.CGF;
+    Other.CGF = nullptr;
+    return *this;
+  }
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Good catch! Since the destructor uses `CGF`, the defaulted move assignment operator was wrong!


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Comment at: clang/lib/CodeGen/EHScopeStack.h:151
     Cleanup(Cleanup &&) {}
+    Cleanup &operator=(const Cleanup &) = delete;
     Cleanup() = default;
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Here too; since a user-declared move constructor is present, let's be explicit about support for move assignment.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D150411/new/

https://reviews.llvm.org/D150411