1 files changed, 13 insertions, 0 deletions
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 982c4cbee88..9287ffd3d6e 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -9356,6 +9356,19 @@ void ASTReader::finishPendingActions() {
                                PBEnd = PendingBodies.end();
        PB != PBEnd; ++PB) {
     if (FunctionDecl *FD = dyn_cast<FunctionDecl>(PB->first)) {
+      // For a function defined inline within a class template, force the
+      // canonical definition to be the one inside the canonical definition of
+      // the template. This ensures that we instantiate from a correct view
+      // of the template.
+      //
+      // Sadly we can't do this more generally: we can't be sure that all
+      // copies of an arbitrary class definition will have the same members
+      // defined (eg, some member functions may not be instantiated, and some
+      // special members may or may not have been implicitly defined).
+      if (auto *RD = dyn_cast<CXXRecordDecl>(FD->getLexicalParent()))
+        if (RD->isDependentContext() && !RD->isThisDeclarationADefinition())
+          continue;
+
       // FIXME: Check for =delete/=default?
       // FIXME: Complain about ODR violations here?
       const FunctionDecl *Defn = nullptr;