diff -Naur gn-39a87c0b-original/src/gn/err.h gn-39a87c0b/src/gn/err.h
--- gn-39a87c0b-original/src/gn/err.h	2021-05-11 06:58:33.000000000 -0400
+++ gn-39a87c0b/src/gn/err.h	2021-05-11 08:33:58.379386372 -0400
@@ -56,7 +56,7 @@
       const std::string& help_text = std::string());
 
   Err(const Err& other);
-
+  Err& operator=(const Err& other) = default;
   ~Err();
 
   bool has_error() const { return has_error_; }
diff -Naur gn-39a87c0b-original/src/gn/label_pattern.h gn-39a87c0b/src/gn/label_pattern.h
--- gn-39a87c0b-original/src/gn/label_pattern.h	2021-05-11 06:58:33.000000000 -0400
+++ gn-39a87c0b/src/gn/label_pattern.h	2021-05-11 08:34:19.399513188 -0400
@@ -33,6 +33,7 @@
                std::string_view name,
                const Label& toolchain_label);
   LabelPattern(const LabelPattern& other);
+  LabelPattern& operator=(const LabelPattern& other) = default;
   ~LabelPattern();
 
   // Converts the given input string to a pattern. This does special stuff
diff -Naur gn-39a87c0b-original/src/gn/substitution_list.h gn-39a87c0b/src/gn/substitution_list.h
--- gn-39a87c0b-original/src/gn/substitution_list.h	2021-05-11 06:58:33.000000000 -0400
+++ gn-39a87c0b/src/gn/substitution_list.h	2021-05-11 08:34:42.355651684 -0400
@@ -15,6 +15,7 @@
  public:
   SubstitutionList();
   SubstitutionList(const SubstitutionList& other);
+  SubstitutionList& operator=(const SubstitutionList& other) = default;
   ~SubstitutionList();
 
   bool Parse(const Value& value, Err* err);
diff -Naur gn-39a87c0b-original/src/gn/substitution_pattern.h gn-39a87c0b/src/gn/substitution_pattern.h
--- gn-39a87c0b-original/src/gn/substitution_pattern.h	2021-05-11 06:58:33.000000000 -0400
+++ gn-39a87c0b/src/gn/substitution_pattern.h	2021-05-11 08:34:50.294699582 -0400
@@ -35,6 +35,7 @@
 
   SubstitutionPattern();
   SubstitutionPattern(const SubstitutionPattern& other);
+  SubstitutionPattern& operator=(const SubstitutionPattern& other) = default;
   ~SubstitutionPattern();
 
   // Parses the given string and fills in the pattern. The pattern must only