diff --git a/Sources/P4Compiler/Declarations.swift b/Sources/P4Compiler/Declarations.swift
index ce060ea..dc223cf 100644
--- a/Sources/P4Compiler/Declarations.swift
+++ b/Sources/P4Compiler/Declarations.swift
@@ -614,6 +614,17 @@ extension Action: Compilable {
     }
     current_context = updated_context
 
+    // Check whether the parameters are in the proper order.
+    let remaining_parameters = action_parameters.parameters.drop(while: {
+      $0.type.direction() != .none
+    })
+    if remaining_parameters.contains(where: { $0.type.direction() != .none }) {
+      return .Error(
+        ErrorWithLocation(
+          sourceLocation: current_node!.toSourceLocation(),
+          withError: "All parameters with direction must precede directionless parameters"))
+    }
+
     walker.next()
     #MustOr(
       result: current_node, thing: walker.getNext(),
diff --git a/Tests/p4rseTests/ControlTests/Compile.swift b/Tests/p4rseTests/ControlTests/Compile.swift
index 62b064e..3c29f03 100644
--- a/Tests/p4rseTests/ControlTests/Compile.swift
+++ b/Tests/p4rseTests/ControlTests/Compile.swift
@@ -18,12 +18,12 @@
 import Common
 import Foundation
 import Macros
+import P4Lang
 import Runtime
 import SwiftTreeSitter
 import Testing
 import TreeSitter
 import TreeSitterP4
-import P4Lang
 
 @testable import P4Compiler
 
@@ -319,4 +319,81 @@ import P4Lang
       ),
       Program.Compile(simple_parser_declaration))
   )
-}
\ No newline at end of file
+}
+
+@Test func test_simple_control_declaration_with_action_with_params_right_order() async throws {
+  let simple_parser_declaration = """
+    control simple(int x, int y) {
+      action a(inout int ax, bool ay) {
+        ax = 5;
+      }
+      table t {
+        key = {
+          x: exact;
+          y: exact;
+        }
+      }
+      apply {
+      }
+    };
+    """
+
+  let x = { (tipe: P4QualifiedType) -> Bool in
+    switch tipe.baseType() {
+    case let c as Control: c.name == "simple"
+    default: false
+    }
+  }
+  let program = try! #UseOkResult(Program.Compile(simple_parser_declaration))
+  #expect(program.InstancesWithTypes(x).count == 1)
+}
+
+@Test func test_simple_control_declaration_with_action_with_params_wrong_order() async throws {
+  let simple_parser_declaration = """
+    control simple(int x, int y) {
+      action a(int ax, inout bool ay) {
+        ay = false;
+      }
+      table t {
+        key = {
+          x: exact;
+          y: exact;
+        }
+      }
+      apply {
+      }
+    };
+    """
+  #expect(
+    #RequireErrorResult(
+      ErrorWithLocation(
+        sourceLocation: SourceLocation(41, 23),
+        withError: "All parameters with direction must precede directionless parameters"),
+      Program.Compile(simple_parser_declaration))
+  )
+}
+
+@Test func test_simple_control_declaration_with_action_with_params_wrong_order_interspersed() async throws {
+  let simple_parser_declaration = """
+    control simple(int x, int y) {
+      action a(inout bool aa, int ax, inout bool ay) {
+        aa = false;
+      }
+      table t {
+        key = {
+          x: exact;
+          y: exact;
+        }
+      }
+      apply {
+      }
+    };
+    """
+  #expect(
+    #RequireErrorResult(
+      ErrorWithLocation(
+        sourceLocation: SourceLocation(41, 38),
+        withError: "All parameters with direction must precede directionless parameters"),
+      Program.Compile(simple_parser_declaration))
+  )
+}