From caddcccea5b770901ef1ebf292defac48f8dda02 Mon Sep 17 00:00:00 2001
From: Lukas Wirth <lukastw97@gmail.com>
Date: Mon, 13 May 2024 17:02:08 +0200
Subject: [PATCH] `parse_macro_expansion_error` almost never contains values so
 `Option` it

---
 crates/hir-expand/src/db.rs         | 13 +++++++++----
 crates/hir/src/lib.rs               |  8 +++++---
 crates/ide-diagnostics/src/tests.rs |  1 -
 3 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/crates/hir-expand/src/db.rs b/crates/hir-expand/src/db.rs
index 895cf20224..2e5fa6131a 100644
--- a/crates/hir-expand/src/db.rs
+++ b/crates/hir-expand/src/db.rs
@@ -129,11 +129,10 @@ pub trait ExpandDatabase: SourceDatabase {
     /// user wrote in the file that defines the proc-macro.
     fn proc_macro_span(&self, fun: AstId<ast::Fn>) -> Span;
     /// Firewall query that returns the errors from the `parse_macro_expansion` query.
-    // FIXME: Option<Arc<...>>
     fn parse_macro_expansion_error(
         &self,
         macro_call: MacroCallId,
-    ) -> ExpandResult<Arc<[SyntaxError]>>;
+    ) -> Option<Arc<ExpandResult<Arc<[SyntaxError]>>>>;
 }
 
 /// This expands the given macro call, but with different arguments. This is
@@ -358,8 +357,14 @@ fn parse_macro_expansion(
 fn parse_macro_expansion_error(
     db: &dyn ExpandDatabase,
     macro_call_id: MacroCallId,
-) -> ExpandResult<Arc<[SyntaxError]>> {
-    db.parse_macro_expansion(MacroFileId { macro_call_id }).map(|it| it.0.errors().into())
+) -> Option<Arc<ExpandResult<Arc<[SyntaxError]>>>> {
+    let e: ExpandResult<Arc<[SyntaxError]>> =
+        db.parse_macro_expansion(MacroFileId { macro_call_id }).map(|it| Arc::from(it.0.errors()));
+    if e.value.is_empty() && e.err.is_none() {
+        None
+    } else {
+        Some(Arc::new(e))
+    }
 }
 
 pub(crate) fn parse_with_map(
diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index 6dd1801dae..079aa90600 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -831,13 +831,15 @@ fn macro_call_diagnostics(
     macro_call_id: MacroCallId,
     acc: &mut Vec<AnyDiagnostic>,
 ) {
-    let ValueResult { value: parse_errors, err } = db.parse_macro_expansion_error(macro_call_id);
-
+    let Some(e) = db.parse_macro_expansion_error(macro_call_id) else {
+        return;
+    };
+    let ValueResult { value: parse_errors, err } = &*e;
     if let Some(err) = err {
         let loc = db.lookup_intern_macro_call(macro_call_id);
         let (node, precise_location, macro_name, kind) = precise_macro_call_location(&loc.kind, db);
         let diag = match err {
-            hir_expand::ExpandError::UnresolvedProcMacro(krate) => {
+            &hir_expand::ExpandError::UnresolvedProcMacro(krate) => {
                 UnresolvedProcMacro { node, precise_location, macro_name, kind, krate }.into()
             }
             err => MacroError { node, precise_location, message: err.to_string() }.into(),
diff --git a/crates/ide-diagnostics/src/tests.rs b/crates/ide-diagnostics/src/tests.rs
index 8bf062fd61..cd5e95cc1e 100644
--- a/crates/ide-diagnostics/src/tests.rs
+++ b/crates/ide-diagnostics/src/tests.rs
@@ -246,7 +246,6 @@ pub(crate) fn check_diagnostics_with_config(config: DiagnosticsConfig, ra_fixtur
             }
         }
         if expected != actual {
-            dbg!(&actual);
             let fneg = expected
                 .iter()
                 .filter(|x| !actual.contains(x))