Merge #8048

8048: Fix missing unresolved macro diagnostic in function body r=edwin0cheng a=brandondong

This was an issue I found while working on https://github.com/rust-analyzer/rust-analyzer/pull/7970.

**Reproduction:**
1. Call a non-existent macro in a function body.
```
fn main() {
  foo!();
}
```
2. No diagnostics are raised. An unresolved-macro-call diagnostic is expected.
3. If the macro call is instead outside of the function body, this works as expected.

I believe this worked previously and regressed in https://github.com/rust-analyzer/rust-analyzer/pull/7805.

**Behavior prior to https://github.com/rust-analyzer/rust-analyzer/pull/7805:**
- The unresolved-macro-call diagnostic did not exist. Instead, a macro-error diagnostic would be raised with the text "could not resolve macro [path]".
- This was implemented by adding an error to the error sink (https://github.com/rust-analyzer/rust-analyzer/pull/7805/files#diff-50a326c5ae465bd9b31ee4310186380aa06e4fa1f6b41dbc0aed5bcc656a3cb8L657).
- The error was propagated through https://github.com/rust-analyzer/rust-analyzer/blob/1a82af3527e476d52410ff4dfd2fb4c57466abcb/crates/hir_def/src/body.rs#L123 eventually reaching https://github.com/rust-analyzer/rust-analyzer/blob/1a82af3527e476d52410ff4dfd2fb4c57466abcb/crates/hir_def/src/body/lower.rs#L569.

**Behavior after:**
- Instead of writing to the error sink, an UnresolvedMacro error is now returned (https://github.com/rust-analyzer/rust-analyzer/pull/7805/files#diff-50a326c5ae465bd9b31ee4310186380aa06e4fa1f6b41dbc0aed5bcc656a3cb8R631).
- The parent caller throws away the error as its function signature is `Option<MacroCallId>` (https://github.com/rust-analyzer/rust-analyzer/pull/7805/files#diff-50a326c5ae465bd9b31ee4310186380aa06e4fa1f6b41dbc0aed5bcc656a3cb8R604).
- We instead now reach the warn condition (https://github.com/rust-analyzer/rust-analyzer/blob/1a82af3527e476d52410ff4dfd2fb4c57466abcb/crates/hir_def/src/body.rs#L124) and no diagnostics are created in https://github.com/rust-analyzer/rust-analyzer/blob/1a82af3527e476d52410ff4dfd2fb4c57466abcb/crates/hir_def/src/body/lower.rs#L575.

**Fix:**
- Make sure to propagate the UnresolvedMacro error. Report the error using the new unresolved-macro-call diagnostic.


Co-authored-by: Brandon <[email protected]>

1 files changed, 20 insertions, 17 deletions

diff --git a/crates/hir_def/src/data.rs b/crates/hir_def/src/data.rs
index 74a2194e5..1a27f7bf2 100644
--- a/crates/hir_def/src/data.rs
+++ b/crates/hir_def/src/data.rs
@@ -267,23 +267,26 @@ fn collect_items(
                 let ast_id_map = db.ast_id_map(file_id);
                 let root = db.parse_or_expand(file_id).unwrap();
                 let call = ast_id_map.get(call.ast_id).to_node(&root);
-
-                if let Some((mark, mac)) = expander.enter_expand(db, call).value {
-                    let src: InFile<ast::MacroItems> = expander.to_source(mac);
-                    let item_tree = db.item_tree(src.file_id);
-                    let iter =
-                        item_tree.top_level_items().iter().filter_map(ModItem::as_assoc_item);
-                    items.extend(collect_items(
-                        db,
-                        module,
-                        expander,
-                        iter,
-                        src.file_id,
-                        container,
-                        limit - 1,
-                    ));
-
-                    expander.exit(db, mark);
+                let res = expander.enter_expand(db, call);
+
+                if let Ok(res) = res {
+                    if let Some((mark, mac)) = res.value {
+                        let src: InFile<ast::MacroItems> = expander.to_source(mac);
+                        let item_tree = db.item_tree(src.file_id);
+                        let iter =
+                            item_tree.top_level_items().iter().filter_map(ModItem::as_assoc_item);
+                        items.extend(collect_items(
+                            db,
+                            module,
+                            expander,
+                            iter,
+                            src.file_id,
+                            container,
+                            limit - 1,
+                        ));
+
+                        expander.exit(db, mark);
+                    }
                 }
             }
         }