diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index bd102b186..3b8c0b9c1 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -465,12 +465,6 @@ ErrorBuilder<ErrorType> & ErrorBuilder<ErrorType>::withFrame(const Env & env, co
     return *this;
 }
 
-template<class ErrorType>
-void ErrorBuilder<ErrorType>::debugThrow() {
-    // NOTE: We always use the -LastTrace version as we push the new trace in withFrame()
-    state.debugThrowLastTrace(ErrorType(info));
-}
-
 
 EvalState::EvalState(
     const Strings & _searchPath,
diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh
index ff407d090..5e88eb950 100644
--- a/src/libexpr/eval.hh
+++ b/src/libexpr/eval.hh
@@ -124,7 +124,11 @@ class ErrorBuilder
         ErrorBuilder<ErrorType> & withFrame(const Env & e, const Expr & ex);
 
         [[gnu::noinline, gnu::noreturn]]
-        void debugThrow();
+        void ErrorBuilder<ErrorType>::debugThrow() {
+            // NOTE: We always use the -LastTrace version as we push the new trace in withFrame()
+            state.debugThrowLastTrace(ErrorType(info));
+        }
+
 };