diff --git a/src/codegen/types/interface-struct-generator.ts b/src/codegen/types/interface-struct-generator.ts
index d7b6949f..f1f83c67 100644
--- a/src/codegen/types/interface-struct-generator.ts
+++ b/src/codegen/types/interface-struct-generator.ts
@@ -159,7 +159,7 @@ export class InterfaceStructGenerator {
 
   private tsTypeToLlvmForField(fieldName: string, tsType: string): string {
     if (tsType === null || tsType === undefined || tsType === "") {
-      return "i8*";
+      throw new Error(`tsTypeToLlvmForField: empty type for field '${fieldName}'`);
     }
     if (this.interfaceStructs.has(tsType)) {
       return "i8*";
@@ -171,7 +171,7 @@ export class InterfaceStructGenerator {
 
   private tsTypeToLlvm(tsType: string): string {
     if (tsType === null || tsType === undefined || tsType === "") {
-      return "i8*";
+      throw new Error("tsTypeToLlvm: empty type");
     }
     if (this.interfaceStructs.has(tsType)) {
       return "i8*";
diff --git a/src/codegen/types/objects/class.ts b/src/codegen/types/objects/class.ts
index 66c5bf10..9477c011 100644
--- a/src/codegen/types/objects/class.ts
+++ b/src/codegen/types/objects/class.ts
@@ -128,6 +128,15 @@ export class ClassGenerator {
         if (this.isEnumType(ts)) {
           return "double";
         }
+        if (ts === "string" || ts === "void" || ts === "any" || ts === "unknown" || ts === "object")
+          return "i8*";
+        if (ts === "null" || ts === "undefined" || ts === "never") return "i8*";
+        if (ts.indexOf(" | ") !== -1) return "i8*";
+        if (ts.startsWith("{")) return "i8*";
+        if (ts.startsWith('"')) return "i8*";
+        if (ts.indexOf("=>") !== -1 || ts.startsWith("(")) return "i8*";
+        if (ts === "i8*" || ts === "i1") return ts;
+        if (ts.startsWith("%")) return ts;
         return "i8*";
       }
       if (ft === "double") return "double";
@@ -170,6 +179,15 @@ export class ClassGenerator {
         if (this.isEnumType(ts)) {
           return "double";
         }
+        if (ts === "string" || ts === "void" || ts === "any" || ts === "unknown" || ts === "object")
+          return "i8*";
+        if (ts === "null" || ts === "undefined" || ts === "never") return "i8*";
+        if (ts.indexOf(" | ") !== -1) return "i8*";
+        if (ts.startsWith("{")) return "i8*";
+        if (ts.startsWith('"')) return "i8*";
+        if (ts.indexOf("=>") !== -1 || ts.startsWith("(")) return "i8*";
+        if (ts === "i8*" || ts === "i1") return ts;
+        if (ts.startsWith("%")) return ts;
         return "i8*";
       }
     }