Disable string type in type checker

compiler/passes/src/type_checking/check_expressions.rs

@@ -601,7 +601,10 @@ impl<'a> ExpressionVisitor<'a> for TypeChecker<'a> {
             },
             Literal::Group(_) => self.assert_and_return_type(Type::Group, expected, input.span()),
             Literal::Scalar(_, _) => self.assert_and_return_type(Type::Scalar, expected, input.span()),
-            Literal::String(_, _) => self.assert_and_return_type(Type::String, expected, input.span()),
+            Literal::String(_, _) => {
+                self.emit_err(TypeCheckerError::strings_are_not_supported(input.span()));
+                self.assert_and_return_type(Type::String, expected, input.span())
+            }
         })
     }
 

compiler/passes/src/type_checking/checker.rs

@@ -387,6 +387,10 @@ impl<'a> TypeChecker<'a> {
     /// Emits an error if the type is not valid.
     pub(crate) fn assert_type_is_valid(&self, span: Span, type_: &Type) {
         match type_ {
+            // String types are temporarily disabled.
+            Type::String => {
+                self.emit_err(TypeCheckerError::strings_are_not_supported(span));
+            }
             // Check that the named composite type has been defined.
             Type::Identifier(identifier) if self.symbol_table.borrow().lookup_struct(identifier.name).is_none() => {
                 self.emit_err(TypeCheckerError::undefined_type(identifier.name, span));

errors/src/errors/type_checker/type_checker_error.rs

@@ -430,4 +430,11 @@ create_messages!(
         msg: format!("Loop bound must be a literal."),
         help: None,
     }
+
+    @formatted
+    strings_are_not_supported {
+        args: (),
+        msg: format!("Strings are not yet supported."),
+        help: None,
+    }
 );