1 files changed, 7 insertions, 0 deletions
diff --git a/include/llvm/IR/DebugInfo.h b/include/llvm/IR/DebugInfo.h
index 69beaada9c..bf3ae98381 100644
--- a/include/llvm/IR/DebugInfo.h
+++ b/include/llvm/IR/DebugInfo.h
@@ -197,6 +197,13 @@ typedef DIRef<DIScope> DIScopeRef;
 typedef DIRef<DIType> DITypeRef;
 
 /// DIScope - A base class for various scopes.
+///
+/// Although, implementation-wise, DIScope is the parent class of most
+/// other DIxxx classes, including DIType and its descendants, most of
+/// DIScope’s descendants are not a substitutable subtype of
+/// DIScope. The DIDescriptor::isScope() method only is true for
+/// DIScopes that are scopes in the strict lexical scope sense
+/// (DICompileUnit, DISubprogram, etc.), but not for, e.g., a DIType.
 class DIScope : public DIDescriptor {
 protected:
   friend class DIDescriptor;