Remove unused "+" on expressions

To concatenate lists (the only ability the "+" operator had),
use "++".

1 files changed, 0 insertions, 5 deletions

diff --git a/src/buildtool/build_engine/expression/expression_ptr.cpp b/src/buildtool/build_engine/expression/expression_ptr.cpp
index 97cdb138..9d249412 100644
--- a/src/buildtool/build_engine/expression/expression_ptr.cpp
+++ b/src/buildtool/build_engine/expression/expression_ptr.cpp
@@ -78,11 +78,6 @@ auto ExpressionPtr::Make(linked_map_t&& map) -> ExpressionPtr {
     return ExpressionPtr{std::move(map)};
 }
 
-auto operator+(ExpressionPtr const& lhs, ExpressionPtr const& rhs)
-    -> ExpressionPtr {
-    return ExpressionPtr{*lhs + *rhs};
-}
-
 auto std::hash<ExpressionPtr>::operator()(ExpressionPtr const& p) const noexcept
     -> std::size_t {
     return std::hash<Expression>{}(*p);