Feature gate type import

src/lazy/expanded/struct.rs

@@ -4,7 +4,6 @@ use crate::lazy::decoder::{Decoder, LazyRawFieldName, LazyRawStruct};
 use crate::lazy::expanded::macro_evaluator::{
     MacroEvaluator, MacroExpr, MacroExprArgsIterator, ValueExpr,
 };
-use crate::lazy::expanded::r#struct::tooling::FieldExprIterator;
 use crate::lazy::expanded::sequence::Environment;
 use crate::lazy::expanded::template::{
     TemplateElement, TemplateMacroRef, TemplateStructFieldExprIterator, TemplateStructIndex,
@@ -17,6 +16,9 @@ use crate::result::IonFailure;
 use crate::{try_next, try_or_some_err, EExpression, HasRange, IonResult, RawSymbolRef, SymbolRef};
 use std::ops::Range;
 
+#[cfg(feature = "experimental-tooling-apis")]
+use crate::lazy::expanded::r#struct::tooling::FieldExprIterator;
+
 /// A unified type embodying all possible field representations coming from both input data
 /// (i.e. raw structs of some encoding) and template bodies.
 // LazyRawStruct implementations have a `unexpanded_fields` method that lifts its raw fields into