From 1f69c8569563955e63ffd760a9e9e3341f97743e Mon Sep 17 00:00:00 2001
From: Rory Neithinger <rneithinger@offchainlabs.com>
Date: Tue, 20 Aug 2024 15:34:42 -0700
Subject: [PATCH] L-09 Don't allow constant keyword in interfaces

This keyword has been unsupported in solidity since 0.5.0.
---
 stylus-proc/src/calls/mod.rs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/stylus-proc/src/calls/mod.rs b/stylus-proc/src/calls/mod.rs
index 53884e3..2ff72ce 100644
--- a/stylus-proc/src/calls/mod.rs
+++ b/stylus-proc/src/calls/mod.rs
@@ -58,9 +58,15 @@ pub fn sol_interface(input: TokenStream) -> TokenStream {
                             error!(attr.span(), "more than one purity attribute specified");
                         }
                         purity = Some(match mutability {
-                            Mutability::Constant(_) | Mutability::Pure(_) => Pure,
+                            Mutability::Pure(_) => Pure,
                             Mutability::View(_) => View,
                             Mutability::Payable(_) => Payable,
+                            Mutability::Constant(_) => {
+                                error!(
+                                    mutability.span(),
+                                    "constant mutability no longer supported"
+                                );
+                            }
                         });
                     }
                     FunctionAttribute::Visibility(vis) => {