[clang] Propagate lifetimebound from formal parameters to those in the canonical declaration and use that for analysis (PR #107627)

[Ilya Biryukov via cfe-commits]

================
@@ -3250,26 +3285,17 @@ static void mergeParamDeclAttributes(ParmVarDecl *newDecl,
            diag::note_carries_dependency_missing_first_decl) << 1/*Param*/;
   }
 
-  if (!oldDecl->hasAttrs())
-    return;
-
-  bool foundAny = newDecl->hasAttrs();
-
-  // Ensure that any moving of objects within the allocated map is
-  // done before we process them.
-  if (!foundAny) newDecl->setAttrs(AttrVec());
-
-  for (const auto *I : oldDecl->specific_attrs<InheritableParamAttr>()) {
-    if (!DeclHasAttr(newDecl, I)) {
-      InheritableAttr *newAttr =
-        cast<InheritableParamAttr>(I->clone(S.Context));
-      newAttr->setInherited(true);
-      newDecl->addAttr(newAttr);
-      foundAny = true;
-    }
-  }
-
-  if (!foundAny) newDecl->dropAttrs();
+  propagateAttributes(
+      newDecl, oldDecl, [&S](ParmVarDecl *toDecl, const ParmVarDecl *fromDecl) {
+        unsigned found = 0;
+        found += propagateAttribute<InheritableParamAttr>(toDecl, fromDecl, S);
+        // Propagate the lifetimebound attribute from parameters to the
+        // most recent declaration. Note that this doesn't include the implicit
+        // 'this' parameter, as the attribute is applied to the function type in
+        // that case.
+        found += propagateAttribute<LifetimeBoundAttr>(toDecl, fromDecl, S);
----------------
ilya-biryukov wrote:

> It doesn't seem like InheritableParamAttr works on types. In any case, other attributes indicate they have this problem too, so let's worry about solving it separately for all of them in the future?

okay, that's something we can also do in a follow-up.

https://github.com/llvm/llvm-project/pull/107627