Fix argument-dependent lookup syntax, thanks to clang

(the bad code is incorrectly compiled by g++)

tests/FixturesForBuiltinT.hpp

+#ifndef FIXTURES_FOR_BUILTIN_T_HPP
+#define FIXTURES_FOR_BUILTIN_T_HPP
+
+#include <language/utils/ASTNodeDataTypeTraits.hpp>
+
+#include <memory>
+#include <stdexcept>
+
+template <>
+inline ASTNodeDataType ast_node_data_type_from<std::shared_ptr<const double>> =
+  ASTNodeDataType::build<ASTNodeDataType::type_id_t>("builtin_t");
+const auto builtin_data_type = ast_node_data_type_from<std::shared_ptr<const double>>;
+
+inline std::shared_ptr<const double>
+operator-(const std::shared_ptr<const double>& p_a)
+{
+  return std::make_shared<double>(-*p_a);
+}
+
+inline std::shared_ptr<const double>
+operator+(const std::shared_ptr<const double>& p_a, const std::shared_ptr<const double>& p_b)
+{
+  return std::make_shared<double>(*p_a + *p_b);
+}
+
+inline std::shared_ptr<const double>
+operator+(std::shared_ptr<const double> p_a, double b)
+{
+  return std::make_shared<double>(*p_a + b);
+}
+
+inline std::shared_ptr<const double>
+operator+(double a, const std::shared_ptr<const double>& p_b)
+{
+  return std::make_shared<double>(a + *p_b);
+}
+
+inline std::shared_ptr<const double>
+operator/(const std::shared_ptr<const double>&, const std::shared_ptr<const double>&)
+{
+  throw std::runtime_error("runtime error both");
+}
+
+inline std::shared_ptr<const double>
+operator/(const std::shared_ptr<const double>&, double)
+{
+  throw std::runtime_error("runtime error lhs");
+}
+
+inline std::shared_ptr<const double>
+operator/(double, const std::shared_ptr<const double>&)
+{
+  throw std::runtime_error("runtime error rhs");
+}
+
+#endif   // FIXTURES_FOR_BUILTIN_T_HPP

tests/test_UnaryExpressionProcessor.cpp

 #include <catch2/catch_test_macros.hpp>
 #include <catch2/matchers/catch_matchers_all.hpp>
 
+#include <FixturesForBuiltinT.hpp>
+
 #include <language/ast/ASTBuilder.hpp>
 #include <language/ast/ASTModulesImporter.hpp>
 #include <language/ast/ASTNodeDataTypeBuilder.hpp>
@@ -63,17 +65,6 @@
     REQUIRE_THROWS_WITH(ASTNodeDataTypeBuilder{*ast}, error_message); \
   }
 
-template <>
-inline ASTNodeDataType ast_node_data_type_from<std::shared_ptr<const double>> =
-  ASTNodeDataType::build<ASTNodeDataType::type_id_t>("builtin_t");
-const auto builtin_data_type = ast_node_data_type_from<std::shared_ptr<const double>>;
-
-inline std::shared_ptr<const double>
-operator-(const std::shared_ptr<const double>& p_a)
-{
-  return std::make_shared<double>(-*p_a);
-}
-
 // clazy:excludeall=non-pod-global-static
 
 TEST_CASE("UnaryExpressionProcessor", "[language]")