[clang] [clang-tools-extra] [clang] Heuristic resolution for explicit object parameter (PR #155143)

[Yanzuo Liu via cfe-commits]

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@@ -301,9 +302,34 @@ std::vector<const NamedDecl *> HeuristicResolverImpl::resolveMemberExpr(
     return {};
   }
 
+  // check if member expr is in the context of an explicit object method
+  // If so, it's safe to assume the templated arg is of type of the record
+  const auto ExplicitMemberHeuristic =
+      [&](const Expr *Base) -> std::optional<QualType> {
+    if (auto *DeclRef = dyn_cast_if_present<DeclRefExpr>(Base)) {
+      auto *PrDecl = dyn_cast_if_present<ParmVarDecl>(DeclRef->getDecl());
+
+      if (PrDecl && PrDecl->isExplicitObjectParameter()) {
+        auto CxxRecord = dyn_cast_if_present<CXXRecordDecl>(
+            PrDecl->getDeclContext()->getParent());
+
+        if (CxxRecord) {
+          return Ctx.getTypeDeclType(dyn_cast<TypeDecl>(CxxRecord));
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zwuis wrote:

`TypeDecl` is an indirect base class of `CXXRecordDecl`. `dyn_cast` can be removed. (Inheritance diagram in <https://clang.llvm.org/doxygen> may be useful)

https://github.com/llvm/llvm-project/pull/155143