diff --git a/common/parser.cc b/common/parser.cc
index 76c0cac9..86db1413 100644
--- a/common/parser.cc
+++ b/common/parser.cc
@@ -24,6 +24,25 @@
 #include <common/log.hh>
 #include <common/parser.hh>
 
+// parser_source_location
+
+parser_source_location::parser_source_location() = default;
+parser_source_location::parser_source_location(const std::string &source) : source_name(std::make_unique<std::string>(source)) { }
+parser_source_location::parser_source_location(const char *source) : source_name(std::make_unique<std::string>(source)) { }
+parser_source_location::parser_source_location(const std::string &source, size_t line) : source_name(std::make_unique<std::string>(source)), line_number(line) { }
+parser_source_location::parser_source_location(const char *source, size_t line) : source_name(std::make_unique<std::string>(source)), line_number(line) { }
+
+parser_source_location::operator bool() const { return source_name != nullptr; }
+
+parser_source_location parser_source_location::on_line(size_t new_line) const
+{
+    parser_source_location loc(*this);
+    loc.line_number = new_line;
+    return loc;
+}
+
+// parser_t
+
 parser_t::parser_t(const void *start, size_t length, parser_source_location base_location)
     : parser_base_t(base_location.on_line(1)),
       pos(reinterpret_cast<const char *>(start)), end(reinterpret_cast<const char *>(start) + length)
diff --git a/include/common/parser.hh b/include/common/parser.hh
index 825d0df6..13b332e3 100644
--- a/include/common/parser.hh
+++ b/include/common/parser.hh
@@ -56,31 +56,26 @@ struct parser_source_location
     // by a source or line, but they are derived from a mapbrush_t which does have
     // a location. The object it points to must outlive this object. this is mainly
     // for debugging.
-    std::optional<std::reference_wrapper<const parser_source_location>> derivative = std::nullopt;
+    const parser_source_location *derivative = nullptr;
 
-    parser_source_location() = default;
-    inline parser_source_location(const std::string &source) : source_name(std::make_unique<std::string>(source)) { }
-    inline parser_source_location(const char *source) : source_name(std::make_unique<std::string>(source)) { }
-    inline parser_source_location(const std::string &source, size_t line) : source_name(std::make_unique<std::string>(source)), line_number(line) { }
-    inline parser_source_location(const char *source, size_t line) : source_name(std::make_unique<std::string>(source)), line_number(line) { }
+    parser_source_location();
+    parser_source_location(const std::string &source);
+    parser_source_location(const char *source);
+    parser_source_location(const std::string &source, size_t line);
+    parser_source_location(const char *source, size_t line);
 
     // check if this source location is valid
-    explicit operator bool() const { return source_name != nullptr; }
+    explicit operator bool() const;
 
     // return a modified source location with only the line changed
-    inline parser_source_location on_line(size_t new_line) const
-    {
-        parser_source_location loc(*this);
-        loc.line_number = new_line;
-        return loc;
-    }
+    parser_source_location on_line(size_t new_line) const;
 
     // return a new, constructed source location derived from this one
     template<typename ... Args>
     inline parser_source_location derive(Args&&... args)
     {
         parser_source_location loc(std::forward<Args>(args)...);
-        loc.derivative = *this;
+        loc.derivative = this;
         return loc;
     }