diff --git a/src/codegen/expressions/calls.ts b/src/codegen/expressions/calls.ts
index 8b9ecb56..36dd6ff8 100644
--- a/src/codegen/expressions/calls.ts
+++ b/src/codegen/expressions/calls.ts
@@ -1170,6 +1170,20 @@ export class CallExpressionGenerator {
       return coerced;
     }
 
+    // FFI null-string coercion: `declare function f(): string` returning NULL
+    // from C should round-trip to TS as the empty string so `result === ""`
+    // works reliably. Only applied to user-declared extern functions (not
+    // internal runtime calls, which rely on NULL sentinels internally).
+    if (returnType === "i8*" && func && func.declare) {
+      const emptyStr = this.ctx.stringGen.doCreateStringConstant("");
+      const isNull = this.ctx.nextTemp();
+      this.ctx.emit(`${isNull} = icmp eq i8* ${temp}, null`);
+      const coerced = this.ctx.nextTemp();
+      this.ctx.emit(`${coerced} = select i1 ${isNull}, i8* ${emptyStr}, i8* ${temp}`);
+      this.ctx.setVariableType(coerced, "i8*");
+      return coerced;
+    }
+
     return temp;
   }
 
diff --git a/src/codegen/infrastructure/assignment-generator.ts b/src/codegen/infrastructure/assignment-generator.ts
index cbb494aa..c56a9c66 100644
--- a/src/codegen/infrastructure/assignment-generator.ts
+++ b/src/codegen/infrastructure/assignment-generator.ts
@@ -419,6 +419,9 @@ export class AssignmentGenerator {
     value: string,
     memberAccessValue: MemberAccessAssignmentNode,
   ): void {
+    if (value.startsWith("__lambda_")) {
+      value = `@${value}`;
+    }
     if (fiTsType) {
       const enumResult = this.isEnumType(fiTsType);
       if (enumResult) {
diff --git a/src/parser-ts/handlers/expressions.ts b/src/parser-ts/handlers/expressions.ts
index c3e75f93..e3879f27 100644
--- a/src/parser-ts/handlers/expressions.ts
+++ b/src/parser-ts/handlers/expressions.ts
@@ -435,7 +435,8 @@ function transformCallExpression(
     };
   } else if (
     ts.isCallExpression(node.expression) ||
-    ts.isParenthesizedExpression(node.expression)
+    ts.isParenthesizedExpression(node.expression) ||
+    ts.isElementAccessExpression(node.expression)
   ) {
     const callee = transformExpression(node.expression, checker);
     return {
diff --git a/tests/fixtures/classes/class-arrow-field-in-ctor.ts b/tests/fixtures/classes/class-arrow-field-in-ctor.ts
new file mode 100644
index 00000000..60b5d299
--- /dev/null
+++ b/tests/fixtures/classes/class-arrow-field-in-ctor.ts
@@ -0,0 +1,12 @@
+// @test-description: issue #587 — arrow literal assigned to class field inside ctor body
+class Foo {
+  cb: (x: number) => number;
+  constructor() {
+    this.cb = (x) => x * 2;
+  }
+}
+
+const f = new Foo();
+if (f.cb(21) === 42) {
+  console.log("TEST_PASSED");
+}
diff --git a/tests/fixtures/edge-cases/call-element-access-callee.ts b/tests/fixtures/edge-cases/call-element-access-callee.ts
new file mode 100644
index 00000000..947f6762
--- /dev/null
+++ b/tests/fixtures/edge-cases/call-element-access-callee.ts
@@ -0,0 +1,12 @@
+// @test-description: issue #589 — parser accepts arr[i](args) as a call expression (ElementAccessExpression callee)
+// @test-compile-error: Immediately invoked function expressions
+function doubler(x: number): number {
+  return x * 2;
+}
+function plusOne(x: number): number {
+  return x + 1;
+}
+
+const fns = [doubler, plusOne];
+const a = fns[0](10);
+console.log(a);
diff --git a/tests/fixtures/edge-cases/ffi-null-string-to-empty.ts b/tests/fixtures/edge-cases/ffi-null-string-to-empty.ts
new file mode 100644
index 00000000..56d81ff3
--- /dev/null
+++ b/tests/fixtures/edge-cases/ffi-null-string-to-empty.ts
@@ -0,0 +1,9 @@
+// @test-description: issue #591 — NULL char* from FFI round-trips to TS as empty string
+declare function getenv(name: string): string;
+
+const v = getenv("__CHADSCRIPT_TEST_VAR_THAT_DOES_NOT_EXIST_91237__");
+if (v === "") {
+  console.log("TEST_PASSED");
+} else {
+  console.log("FAIL: got " + v);
+}