Simplify handle_function_macro for clang 3.9+

Author: kulp

src/clang.rs

@@ -237,14 +237,8 @@ impl Cursor {
     }
 
     /// Is this Cursor pointing to a function-like macro definition?
-    /// Returns None if this cannot be determined with the available libclang
-    /// (it requires 3.9 or greater).
-    pub fn is_macro_function_like(&self) -> Option<bool> {
-        if clang_Cursor_isMacroFunctionLike::is_loaded() {
-            Some(unsafe { clang_Cursor_isMacroFunctionLike(self.x) != 0 })
-        } else {
-            None
-        }
+    pub fn is_macro_function_like(&self) -> bool {
+        unsafe { clang_Cursor_isMacroFunctionLike(self.x) != 0 }
     }
 
     /// Get the kind of referent this cursor is pointing to.

src/ir/var.rs

@@ -141,31 +141,10 @@ fn handle_function_macro(
     tokens: &[ClangToken],
     callbacks: &dyn crate::callbacks::ParseCallbacks,
 ) -> Result<(), ParseError> {
-    fn is_abutting(a: &ClangToken, b: &ClangToken) -> bool {
-        unsafe {
-            clang_sys::clang_equalLocations(
-                clang_sys::clang_getRangeEnd(a.extent),
-                clang_sys::clang_getRangeStart(b.extent),
-            ) != 0
-        }
-    }
-
-    let is_functional_macro =
-        // If we have libclang >= 3.9, we can use `is_macro_function_like()` and
-        // avoid checking for abutting tokens ourselves.
-        cursor.is_macro_function_like().unwrap_or_else(|| {
-            // If we cannot get a definitive answer from clang, we instead check
-            // for a parenthesis token immediately adjacent to (that is,
-            // abutting) the first token in the macro definition.
-            // TODO: Once we don't need the fallback check here, we can hoist
-            // the `is_macro_function_like` check into this function's caller,
-            // and thus avoid allocating the `tokens` vector for non-functional
-            // macros.
-            match tokens.get(0..2) {
-                Some([a, b]) => is_abutting(&a, &b) && b.spelling() == b"(",
-                _ => false,
-            }
-        });
+    // TODO: Hoist the `is_macro_function_like` check into this function's
+    // caller, and thus avoid allocating the `tokens` vector for non-functional
+    // macros.
+    let is_functional_macro = cursor.is_macro_function_like();
 
     if !is_functional_macro {
         return Ok(());