Attempt to fix #130 — clang::Cursor::args should return an Option<Vec<Cursor>>

Author: Rémy HUBSCHER

libbindgen/src/clang.rs

@@ -420,16 +420,26 @@ impl Cursor {
 
     /// Given that this cursor's referent is a function, return cursors to its
     /// parameters.
-    pub fn args(&self) -> Vec<Cursor> {
+    pub fn args(&self) -> Option<Vec<Cursor>> {
+        // XXX: We might want to use and keep num_args
+        // match self.kind() {
+        // CXCursor_FunctionDecl |
+        // CXCursor_CXXMethod => {
         unsafe {
-            let num = self.num_args().expect("expected value, got none") as u32;
-            let mut args = vec![];
-            for i in 0..num {
-                args.push(Cursor {
-                    x: clang_Cursor_getArgument(self.x, i as c_uint),
-                });
+            let w = clang_Cursor_getNumArguments(self.x);
+            if w == -1 {
+                None
+            } else {
+                let num = w as u32;
+
+                let mut args = vec![];
+                for i in 0..num {
+                    args.push(Cursor {
+                        x: clang_Cursor_getArgument(self.x, i as c_uint),
+                    });
+                }
+                Some(args)
             }
-            args
         }
     }
 

libbindgen/src/ir/function.rs

@@ -150,7 +150,7 @@ impl FunctionSig {
             CXCursor_CXXMethod => {
                 // For CXCursor_FunctionDecl, cursor.args() is the reliable way
                 // to get parameter names and types.
-                cursor.args()
+                cursor.args().expect("It cannot be None because we are in a method/function")
                     .iter()
                     .map(|arg| {
                         let arg_ty = arg.cur_type();