fix: Interface default implementation is now an error (#1421)

Author: mhasel

compiler/plc_diagnostics/src/diagnostics/diagnostics_registry.rs

@@ -214,7 +214,7 @@ lazy_static! {
         E110,   Error,      include_str!("./error_codes/E110.md"),  // Invalid POU Type for Interface Implementation
         E111,   Error,      include_str!("./error_codes/E111.md"),  // Duplicate interface methods with different signatures
         E112,   Error,      include_str!("./error_codes/E112.md"),  // Incomplete interface implementation
-        E113,   Warning,    include_str!("./error_codes/E113.md"),  // Interface default method implementation
+        E113,   Error,      include_str!("./error_codes/E113.md"),  // Interface default method implementation
         E114,   Error,      include_str!("./error_codes/E114.md"),  // Multiple extensions of same POU
         E115,   Error,      include_str!("./error_codes/E115.md"),  // Property in unsupported POU type
         E116,   Error,      include_str!("./error_codes/E116.md"),  // Property defined in unsupported variable block

src/parser/tests/interface_parser_tests.rs

@@ -390,15 +390,14 @@ mod error_handling {
         ";
 
         let diagnostics = parse_and_validate_buffered(source);
-        insta::assert_snapshot!(diagnostics, @r###"
-        warning[E113]: Interfaces can not have a default implementations
+        insta::assert_snapshot!(diagnostics, @r"
+        error[E113]: Interfaces can not have a default implementations
           ┌─ <internal>:4:17
           │  
         4 │ ╭                 1 > 2;
         5 │ │                 methodA := 5;
           │ ╰─────────────────────────────^ Interfaces can not have a default implementations
-
-        "###);
+        ");
     }
 
     #[test]