Revert "refactor(rust): simplify logic"

This reverts commit 1486098.

chapi-ast-rust/src/main/kotlin/chapi/ast/rustast/RustAstBaseListener.kt

@@ -4,6 +4,7 @@ import chapi.ast.antlr.RustParser
 import chapi.ast.antlr.RustParser.ItemContext
 import chapi.ast.antlr.RustParser.SimplePathContext
 import chapi.ast.antlr.RustParser.TypePathSegmentContext
+import chapi.ast.antlr.RustParser.Type_Context
 import chapi.ast.antlr.RustParserBaseListener
 import chapi.domain.core.*
 import org.antlr.v4.runtime.ParserRuleContext
@@ -161,13 +162,18 @@ open class RustAstBaseListener(private val fileName: String) : RustParserBaseLis
     private fun buildFields(structFields: RustParser.StructFieldsContext?): List<CodeField> {
         return structFields?.structField()?.map {
             CodeField(
-                TypeType = lookupByType(it.type_()?.text),
+                TypeType = lookupType(it.type_()),
                 Annotations = buildAttribute(it.outerAttribute()),
                 TypeValue = it.identifier()?.text ?: "",
             )
         } ?: emptyList()
     }
 
+    private fun lookupType(type_: Type_Context?): String {
+        val typeText = type_?.text
+        return lookupByType(typeText)
+    }
+
     open fun lookupByType(typeText: String?): String {
         if (typeText == null) return ""
         val text = if (typeText.contains("::")) {