From 2a152c2517bdf04b60a100849f90d31105bc1027 Mon Sep 17 00:00:00 2001
From: evan-schott <53463459+evan-schott@users.noreply.github.com>
Date: Thu, 28 Mar 2024 11:03:57 -0700
Subject: [PATCH] Error for trying to modify external mappings

---
 compiler/passes/src/type_checking/checker.rs       | 14 ++++++++++++++
 .../src/errors/type_checker/type_checker_error.rs  |  7 +++++++
 2 files changed, 21 insertions(+)

diff --git a/compiler/passes/src/type_checking/checker.rs b/compiler/passes/src/type_checking/checker.rs
index 2638d8bf82..906037e26d 100644
--- a/compiler/passes/src/type_checking/checker.rs
+++ b/compiler/passes/src/type_checking/checker.rs
@@ -974,6 +974,13 @@ impl<'a> TypeChecker<'a> {
                 }
                 // Check that the first argument is a mapping.
                 if let Some(mapping_type) = self.assert_mapping_type(&arguments[0].0, arguments[0].1) {
+                    // Cannot modify external mappings.
+                    if mapping_type.program != self.program_name.unwrap() {
+                        self.handler.emit_err(TypeCheckerError::cannot_modify_external_mapping(
+                            "set",
+                            function_span,
+                        ));
+                    }
                     // Check that the second argument matches the key type of the mapping.
                     self.assert_type(&arguments[1].0, &mapping_type.key, arguments[1].1);
                     // Check that the third argument matches the value type of the mapping.
@@ -994,6 +1001,13 @@ impl<'a> TypeChecker<'a> {
                 }
                 // Check that the first argument is a mapping.
                 if let Some(mapping_type) = self.assert_mapping_type(&arguments[0].0, arguments[0].1) {
+                    // Cannot modify external mappings.
+                    if mapping_type.program != self.program_name.unwrap() {
+                        self.handler.emit_err(TypeCheckerError::cannot_modify_external_mapping(
+                            "remove",
+                            function_span,
+                        ));
+                    }
                     // Check that the second argument matches the key type of the mapping.
                     self.assert_type(&arguments[1].0, &mapping_type.key, arguments[1].1);
                     // Return nothing.
diff --git a/errors/src/errors/type_checker/type_checker_error.rs b/errors/src/errors/type_checker/type_checker_error.rs
index e228e0feb0..c784baf75c 100644
--- a/errors/src/errors/type_checker/type_checker_error.rs
+++ b/errors/src/errors/type_checker/type_checker_error.rs
@@ -768,4 +768,11 @@ create_messages!(
         msg: format!("The definition for `{struct_}` in program `{program_1}.aleo` does not match the definition in program `{program_2}.aleo`"),
         help: Some("Check that the struct definition in the current program matches the definition in the imported program.".to_string()),
     }
+    
+    @formatted
+    cannot_modify_external_mapping {
+        args: (operation: impl Display),
+        msg: format!("Cannot use operation `{operation}` to modify external mapping."),
+        help: Some("The only valid operations on external mappings are get, get_or_use, and contains.".to_string()),
+    }
 );