[clang] [dataflow] use unqualified type for smart pointer matching (#125958)

one would assume that `getCanonicalTypeUnqualified` returns an
unqualified type, but sadly one would be wrong. the current logic fails
for std::optional as implemented in libcxx, because Star and Arrow types
mismatch in their const qualification.

there are other places in clang that use
getCanonicalTypeUnqualified().getUnqualifiedType().

Author: fmayer

clang/lib/Analysis/FlowSensitive/SmartPointerAccessorCaching.cpp

@@ -42,15 +42,17 @@ bool hasSmartPointerClassShape(const CXXRecordDecl &RD, bool &HasGet,
         HasStar = true;
         StarReturnType = MD->getReturnType()
                              .getNonReferenceType()
-                             ->getCanonicalTypeUnqualified();
+                             ->getCanonicalTypeUnqualified()
+                             .getUnqualifiedType();
       }
       break;
     case OO_Arrow:
       if (MD->getReturnType()->isPointerType()) {
         HasArrow = true;
         ArrowReturnType = MD->getReturnType()
                               ->getPointeeType()
-                              ->getCanonicalTypeUnqualified();
+                              ->getCanonicalTypeUnqualified()
+                              .getUnqualifiedType();
       }
       break;
     case OO_None: {
@@ -62,14 +64,16 @@ bool hasSmartPointerClassShape(const CXXRecordDecl &RD, bool &HasGet,
           HasGet = true;
           GetReturnType = MD->getReturnType()
                               ->getPointeeType()
-                              ->getCanonicalTypeUnqualified();
+                              ->getCanonicalTypeUnqualified()
+                              .getUnqualifiedType();
         }
       } else if (II->isStr("value")) {
         if (MD->getReturnType()->isReferenceType()) {
           HasValue = true;
           ValueReturnType = MD->getReturnType()
                                 .getNonReferenceType()
-                                ->getCanonicalTypeUnqualified();
+                                ->getCanonicalTypeUnqualified()
+                                .getUnqualifiedType();
         }
       }
     } break;