do not offer fixit for macro expansions and refactor the code

crates/ide-diagnostics/src/handlers/missing_unsafe.rs

@@ -1,7 +1,7 @@
-use hir::db::AstDatabase;
+use hir::db::ExpandDatabase;
 use ide_db::{assists::Assist, source_change::SourceChange};
-use syntax::AstNode;
 use syntax::{ast, SyntaxNode};
+use syntax::{match_ast, AstNode};
 use text_edit::TextEdit;
 
 use crate::{fix, Diagnostic, DiagnosticsContext};
@@ -19,10 +19,15 @@ pub(crate) fn missing_unsafe(ctx: &DiagnosticsContext<'_>, d: &hir::MissingUnsaf
 }
 
 fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::MissingUnsafe) -> Option<Vec<Assist>> {
+    // The fixit will not work correctly for macro expansions, so we don't offer it in that case.
+    if d.expr.file_id.is_macro() {
+        return None;
+    }
+
     let root = ctx.sema.db.parse_or_expand(d.expr.file_id)?;
     let expr = d.expr.value.to_node(&root);
 
-    let node_to_add_unsafe_block = pick_best_node_to_add_unsafe_block(&expr);
+    let node_to_add_unsafe_block = pick_best_node_to_add_unsafe_block(&expr)?;
 
     let replacement = format!("unsafe {{ {} }}", node_to_add_unsafe_block.text());
     let edit = TextEdit::replace(node_to_add_unsafe_block.text_range(), replacement);
@@ -42,72 +47,51 @@ fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::MissingUnsafe) -> Option<Vec<Ass
 // - `unsafe_expr += 1` -> `unsafe { unsafe_expr += 1 }`
 // - `&unsafe_expr` -> `unsafe { &unsafe_expr }`
 // - `&&unsafe_expr` -> `unsafe { &&unsafe_expr }`
-fn pick_best_node_to_add_unsafe_block(unsafe_expr: &ast::Expr) -> SyntaxNode {
+fn pick_best_node_to_add_unsafe_block(unsafe_expr: &ast::Expr) -> Option<SyntaxNode> {
     // The `unsafe_expr` might be:
     // - `ast::CallExpr`: call an unsafe function
     // - `ast::MethodCallExpr`: call an unsafe method
     // - `ast::PrefixExpr`: dereference a raw pointer
     // - `ast::PathExpr`: access a static mut variable
-    for node in unsafe_expr.syntax().ancestors() {
-        let Some(parent) = node.parent() else {
-            return node;
-        };
-        match parent.kind() {
-            syntax::SyntaxKind::METHOD_CALL_EXPR => {
-                // Check if the `node` is the receiver of the method call
-                let method_call_expr = ast::MethodCallExpr::cast(parent.clone()).unwrap();
-                if method_call_expr
-                    .receiver()
-                    .map(|receiver| {
-                        receiver.syntax().text_range().contains_range(node.text_range())
-                    })
-                    .unwrap_or(false)
-                {
-                    // Actually, I think it's not necessary to check whether the
-                    // text range of the `node` (which is the ancestor of the
-                    // `unsafe_expr`) is contained in the text range of the
-                    // receiver. The `node` could potentially be the receiver, the
-                    // method name, or the argument list. Since the `node` is the
-                    // ancestor of the unsafe_expr, it cannot be the method name.
-                    // Additionally, if the `node` is the argument list, the loop
-                    // would break at least when `parent` reaches the argument list.
-                    //
-                    // Dispite this, I still check the text range because I think it
-                    // makes the code easier to understand.
-                    continue;
-                }
-                return node;
-            }
-            syntax::SyntaxKind::FIELD_EXPR | syntax::SyntaxKind::REF_EXPR => continue,
-            syntax::SyntaxKind::BIN_EXPR => {
-                // Check if the `node` is the left-hand side of an assignment
-                let is_left_hand_side_of_assignment = {
-                    let bin_expr = ast::BinExpr::cast(parent.clone()).unwrap();
-                    if let Some(ast::BinaryOp::Assignment { .. }) = bin_expr.op_kind() {
-                        let is_left_hand_side = bin_expr
-                            .lhs()
-                            .map(|lhs| lhs.syntax().text_range().contains_range(node.text_range()))
-                            .unwrap_or(false);
-                        is_left_hand_side
-                    } else {
-                        false
+    for (node, parent) in
+        unsafe_expr.syntax().ancestors().zip(unsafe_expr.syntax().ancestors().skip(1))
+    {
+        match_ast! {
+            match parent {
+                // If the `parent` is a `MethodCallExpr`, that means the `node`
+                // is the receiver of the method call, because only the receiver
+                // can be a direct child of a method call. The method name
+                // itself is not an expression but a `NameRef`, and an argument
+                // is a direct child of an `ArgList`.
+                ast::MethodCallExpr(_) => continue,
+                ast::FieldExpr(_) => continue,
+                ast::RefExpr(_) => continue,
+                ast::BinExpr(it) => {
+                    // Check if the `node` is the left-hand side of an
+                    // assignment, if so, we don't want to wrap it in an unsafe
+                    // block, e.g. `unsafe_expr += 1`
+                    let is_left_hand_side_of_assignment = {
+                        if let Some(ast::BinaryOp::Assignment { .. }) = it.op_kind() {
+                            it.lhs().map(|lhs| lhs.syntax().text_range().contains_range(node.text_range())).unwrap_or(false)
+                        } else {
+                            false
+                        }
+                    };
+                    if !is_left_hand_side_of_assignment {
+                        return Some(node);
                     }
-                };
-                if !is_left_hand_side_of_assignment {
-                    return node;
-                }
-            }
-            _ => {
-                return node;
+                },
+                _ => { return Some(node); }
+
             }
         }
     }
-    unsafe_expr.syntax().clone()
+    None
 }
 
 #[cfg(test)]
 mod tests {
-    use crate::tests::{check_diagnostics, check_fix};
+    use crate::tests::{check_diagnostics, check_fix, check_no_fix};
 
     #[test]
     fn missing_unsafe_diagnostic_with_raw_ptr() {
@@ -467,4 +451,19 @@ fn main() {
 "#,
         )
     }
+
+    #[test]
+    fn unsafe_expr_in_macro_call() {
+        check_no_fix(
+            r#"
+unsafe fn foo() -> u8 {
+    0
+}
+
+fn main() {
+    let x = format!("foo: {}", foo$0());
+}
+            "#,
+        )
+    }
 }