diff --git a/js/src/ion/CodeGenerator.cpp b/js/src/ion/CodeGenerator.cpp
index 905fc097b271..064c9eea97a1 100644
--- a/js/src/ion/CodeGenerator.cpp
+++ b/js/src/ion/CodeGenerator.cpp
@@ -22,6 +22,11 @@ using namespace js::ion;
 namespace js {
 namespace ion {
 
+StringObject *
+MNewStringObject::templateObj() const {
+    return &templateObj_->asString();
+}
+
 CodeGenerator::CodeGenerator(MIRGenerator *gen, LIRGraph &graph)
   : CodeGeneratorSpecific(gen, graph)
 {
diff --git a/js/src/ion/MIR.h b/js/src/ion/MIR.h
index 462ab1ed6040..220e15048443 100644
--- a/js/src/ion/MIR.h
+++ b/js/src/ion/MIR.h
@@ -5311,9 +5311,9 @@ class MNewStringObject :
     MDefinition *input() const {
         return getOperand(0);
     }
-    StringObject *templateObj() const {
-        return &templateObj_->asString();
-    }
+
+    StringObject *templateObj() const;
+
     TypePolicy *typePolicy() {
         return this;
     }