[clang-tidy] fix PR36489 - respect deduced pointer types from auto as well

Summary:
The cppcoreguidelines-pro-bounds-pointer-arithmetic warns on all occassion where
pointer arithmetic is used, but does not check values where the pointer types
is deduced via `auto`. This patch adjusts this behaviour and solved
PR36489.
I accidentally commited a wrong patch, this Differential is meant to have a
correct revision description and code attached to it.
Because the patch was accepted by aaron.ballman already, i will just commit
it.
See https://reviews.llvm.org/D48717 for the old differntial (contains wrong
code from the mixup)

Subscribers: nemanjai, xazax.hun, kbarton, cfe-commits

Differential Revision: https://reviews.llvm.org/D49682

llvm-svn: 337716

1 files changed, 6 insertions, 2 deletions

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsPointerArithmeticCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsPointerArithmeticCheck.cpp
index d664b6401ae..dfbb51bed12 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsPointerArithmeticCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsPointerArithmeticCheck.cpp
@@ -21,12 +21,16 @@ void ProBoundsPointerArithmeticCheck::registerMatchers(MatchFinder *Finder) {
   if (!getLangOpts().CPlusPlus)
     return;
 
+  const auto AllPointerTypes = anyOf(
+      hasType(pointerType()), hasType(autoType(hasDeducedType(pointerType()))),
+      hasType(decltypeType(hasUnderlyingType(pointerType()))));
+
   // Flag all operators +, -, +=, -=, ++, -- that result in a pointer
   Finder->addMatcher(
       binaryOperator(
           anyOf(hasOperatorName("+"), hasOperatorName("-"),
                 hasOperatorName("+="), hasOperatorName("-=")),
-          hasType(pointerType()),
+          AllPointerTypes,
           unless(hasLHS(ignoringImpCasts(declRefExpr(to(isImplicit()))))))
           .bind("expr"),
       this);
@@ -41,7 +45,7 @@ void ProBoundsPointerArithmeticCheck::registerMatchers(MatchFinder *Finder) {
   Finder->addMatcher(
       arraySubscriptExpr(
           hasBase(ignoringImpCasts(
-              anyOf(hasType(pointerType()),
+              anyOf(AllPointerTypes,
                     hasType(decayedType(hasDecayedType(pointerType())))))))
           .bind("expr"),
       this);