move the error for failable functions to show the part where it possibly fails

Author: b1ek

src/modules/function/declaration.rs

@@ -216,13 +216,9 @@ impl SyntaxModule<ParserMetadata> for FunctionDeclaration {
                 }
                 // Parse the body
                 token(meta, "{")?;
-                let (index_begin, index_end, is_failable) = skip_function_body(meta);
-                if (!(is_failable && declared_failable)) && (is_failable || declared_failable) {
-                    if is_failable {
-                        return error!(meta, returns_tok, "Functions that can fail must have a '?' after the type name");
-                    } else {
-                        return error!(meta, returns_tok, "Infallible functions must not have a '?' after the type name");
-                    }
+                let (index_begin, index_end, is_failable) = skip_function_body(meta, declared_failable)?;
+                if is_failable && (!declared_failable) {
+                    return error!(meta, returns_tok, "Infallible functions must not have a '?' after the type name");
                 }
                 // Create a new context with the function body
                 let expr = meta.context.expr[index_begin..index_end].to_vec();

src/modules/function/declaration_utils.rs

@@ -6,23 +6,28 @@ use crate::utils::cc_flags::{CCFlags, get_ccflag_name};
 use crate::utils::context::Context;
 use crate::utils::function_interface::FunctionInterface;
 
-pub fn skip_function_body(meta: &mut ParserMetadata) -> (usize, usize, bool) {
+pub fn skip_function_body(meta: &mut ParserMetadata, declared_failable: bool) -> Result<(usize, usize, bool), Failure> {
     let index_begin = meta.get_index();
     let mut is_failable = false;
     let mut scope = 1;
     while let Some(tok) = meta.get_current_token() {
         match tok.word.as_str() {
             "{" => scope += 1,
             "}" => scope -= 1,
-            "fail" => is_failable = true,
+            "fail" => {
+                if !declared_failable {
+                    return error!(meta, Some(tok), "Functions that can fail must have a '?' after the type name");
+                }
+                is_failable = true
+            },
             "?" => is_failable = true,
             _ => {}
         }
         if scope == 0 { break }
         meta.increment_index();
     }
     let index_end = meta.get_index();
-    (index_begin, index_end, is_failable)
+    Ok((index_begin, index_end, is_failable))
 }
 
 pub fn is_functions_comment_doc(meta: &mut ParserMetadata) -> bool {