[PATCH] D54943: [clang-tidy] implement const-transformation for cppcoreguidelines-const-correctness

[Sam McCall via Phabricator via cfe-commits]

sammccall added inline comments.


================
Comment at: clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt:33
   LINK_LIBS
+  clangAnalysis
   clangTidy
----------------
JonasToth wrote:
> njames93 wrote:
> > Will this work under clangd as I don't think that links in the clangAnalysis libraries @sammccall?
> I did not check if it works and `clangd` does not explicitly link to `Analysis`, but only to the checks.
> Doesn't the `LINK_LIBS` induce transitive dependency resolution for linking?
I don't know whether you need to add it everywhere, I suspect transitive is OK.

In any case this isn't a new dependency, Sema depends on Analysis and clangd depends on Sema.


================
Comment at: clang-tools-extra/clang-tidy/cppcoreguidelines/ConstCorrectnessCheck.cpp:29
+              ast_matchers::internal::Matcher<Decl>, InnerMatcher) {
+  return ast_matchers::internal::matchesFirstInPointerRange(
+      InnerMatcher, Node.decl_begin(), Node.decl_end(), Finder, Builder);
----------------
This returns an iterator (i.e. a pointer), which is being converted to a boolean.

i.e. it's always returning true. I think this is why you're seeing nullptr crashes on Variable.


================
Comment at: clang-tools-extra/clang-tidy/cppcoreguidelines/ConstCorrectnessCheck.cpp:29
+              ast_matchers::internal::Matcher<Decl>, InnerMatcher) {
+  return ast_matchers::internal::matchesFirstInPointerRange(
+      InnerMatcher, Node.decl_begin(), Node.decl_end(), Finder, Builder);
----------------
sammccall wrote:
> This returns an iterator (i.e. a pointer), which is being converted to a boolean.
> 
> i.e. it's always returning true. I think this is why you're seeing nullptr crashes on Variable.
this is depending on `::internal` details, which doesn't seem OK.
I think you'd need to find another way to do it, or move this to ASTMatchers (in a separate patch).


================
Comment at: clang-tools-extra/clang-tidy/cppcoreguidelines/ConstCorrectnessCheck.cpp:102-105
+  // There have been crashes on 'Variable == nullptr', even though the matcher
+  // is not conditional. This comes probably from 'findAll'-matching.
+  if (!Variable || !LocalScope)
+    return;
----------------
JonasToth wrote:
> njames93 wrote:
> > This sounds like a bug that should be raised with ASTMatchers, if its reproducible.
> I found no way to reproduce it (yet).
> The crashes occured during verification on big projects and `run-clang-tidy` kind of obfuscated where the crash happened.
> 
> This is something for the iron out part of the check I think.
This is a bug in a helper added in this patch, I've added a comment above.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D54943/new/

https://reviews.llvm.org/D54943