diff --git a/src/language/ASTBuilder.cpp b/src/language/ASTBuilder.cpp
index ab30b2aaa2ae3b271d60b29035ea94428989eac0..1b7f36b275e57ec7d4357d6c97ae18ca0ab194ca 100644
--- a/src/language/ASTBuilder.cpp
+++ b/src/language/ASTBuilder.cpp
@@ -268,4 +268,4 @@ buildAST(InputT& input)
 }
 
 template std::unique_ptr<language::Node> buildAST(read_input<>& input);
-template std::unique_ptr<language::Node> buildAST(istream_input<>& input);
+template std::unique_ptr<language::Node> buildAST(string_input<>& input);
diff --git a/src/language/ASTBuilder.hpp b/src/language/ASTBuilder.hpp
index 19adacf161b2a330fb89d4145a82816fec698630..76388f3403c4a666bbb755df696e2e6f05a27314 100644
--- a/src/language/ASTBuilder.hpp
+++ b/src/language/ASTBuilder.hpp
@@ -8,7 +8,4 @@
 template <typename InputT>
 std::unique_ptr<language::Node> buildAST(InputT& input);
 
-template <typename InputT>
-std::unique_ptr<language::Node> buildAST(InputT& input);
-
 #endif   // AST_BUILDER_HPP