From 1360b4c3a1d052425276dacf38fc413cee25e4cd Mon Sep 17 00:00:00 2001
From: Chayim Refael Friedman <chayimfr@gmail.com>
Date: Sun, 26 Jan 2025 19:06:29 +0200
Subject: In completion's expand, consider recursion stop condition (when we're
 not inside a macro call anymore) *after* the recursive call instead of before
 it

This is because our detection is imperfect, and miss some cases such as an impersonating `test` macro, so we hope we'll expand successfully in this case.
---
 .../crates/ide-completion/src/context/analysis.rs  | 41 ++++++++++++++----
 .../crates/ide-completion/src/tests/expression.rs  | 50 ++++++++++++++++++++++
 2 files changed, 83 insertions(+), 8 deletions(-)

diff --git a/src/tools/rust-analyzer/crates/ide-completion/src/context/analysis.rs b/src/tools/rust-analyzer/crates/ide-completion/src/context/analysis.rs
index f5a50ae8190..eecd412bc43 100644
--- a/src/tools/rust-analyzer/crates/ide-completion/src/context/analysis.rs
+++ b/src/tools/rust-analyzer/crates/ide-completion/src/context/analysis.rs
@@ -59,7 +59,7 @@ pub(super) fn expand_and_analyze(
     // make the offset point to the start of the original token, as that is what the
     // intermediate offsets calculated in expansion always points to
     let offset = offset - relative_offset;
-    let expansion = expand(
+    let expansion = expand_maybe_stop(
         sema,
         original_file.clone(),
         speculative_file.clone(),
@@ -118,7 +118,7 @@ fn token_at_offset_ignore_whitespace(file: &SyntaxNode, offset: TextSize) -> Opt
 /// that we check, we subtract `COMPLETION_MARKER.len()`. This may not be accurate because proc macros
 /// can insert the text of the completion marker in other places while removing the span, but this is
 /// the best we can do.
-fn expand(
+fn expand_maybe_stop(
     sema: &Semantics<'_, RootDatabase>,
     original_file: SyntaxNode,
     speculative_file: SyntaxNode,
@@ -126,23 +126,48 @@ fn expand(
     fake_ident_token: SyntaxToken,
     relative_offset: TextSize,
 ) -> Option<ExpansionResult> {
-    let _p = tracing::info_span!("CompletionContext::expand").entered();
+    if let result @ Some(_) = expand(
+        sema,
+        original_file.clone(),
+        speculative_file.clone(),
+        original_offset,
+        fake_ident_token.clone(),
+        relative_offset,
+    ) {
+        return result;
+    }
 
+    // This needs to come after the recursive call, because our "inside macro" detection is subtly wrong
+    // with regard to attribute macros named `test` that are not std's test. So hopefully we will expand
+    // them successfully above and be able to analyze.
     // Left biased since there may already be an identifier token there, and we appended to it.
     if !sema.might_be_inside_macro_call(&fake_ident_token)
         && token_at_offset_ignore_whitespace(&original_file, original_offset + relative_offset)
             .is_some_and(|original_token| !sema.might_be_inside_macro_call(&original_token))
     {
         // Recursion base case.
-        return Some(ExpansionResult {
+        Some(ExpansionResult {
             original_file,
             speculative_file,
             original_offset,
             speculative_offset: fake_ident_token.text_range().start(),
             fake_ident_token,
             derive_ctx: None,
-        });
+        })
+    } else {
+        None
     }
+}
+
+fn expand(
+    sema: &Semantics<'_, RootDatabase>,
+    original_file: SyntaxNode,
+    speculative_file: SyntaxNode,
+    original_offset: TextSize,
+    fake_ident_token: SyntaxToken,
+    relative_offset: TextSize,
+) -> Option<ExpansionResult> {
+    let _p = tracing::info_span!("CompletionContext::expand").entered();
 
     let parent_item =
         |item: &ast::Item| item.syntax().ancestors().skip(1).find_map(ast::Item::cast);
@@ -197,7 +222,7 @@ fn expand(
                             // stop here to prevent problems from happening
                             return None;
                         }
-                        let result = expand(
+                        let result = expand_maybe_stop(
                             sema,
                             actual_expansion.clone(),
                             fake_expansion.clone(),
@@ -317,7 +342,7 @@ fn expand(
                                     // stop here to prevent problems from happening
                                     return None;
                                 }
-                                let result = expand(
+                                let result = expand_maybe_stop(
                                     sema,
                                     actual_expansion.clone(),
                                     fake_expansion.clone(),
@@ -386,7 +411,7 @@ fn expand(
                         // stop here to prevent problems from happening
                         return None;
                     }
-                    let result = expand(
+                    let result = expand_maybe_stop(
                         sema,
                         actual_expansion.clone(),
                         fake_expansion.clone(),
diff --git a/src/tools/rust-analyzer/crates/ide-completion/src/tests/expression.rs b/src/tools/rust-analyzer/crates/ide-completion/src/tests/expression.rs
index 663a038580d..37557512837 100644
--- a/src/tools/rust-analyzer/crates/ide-completion/src/tests/expression.rs
+++ b/src/tools/rust-analyzer/crates/ide-completion/src/tests/expression.rs
@@ -1986,3 +1986,53 @@ fn foo() {
         "#]],
     );
 }
+
+#[test]
+fn non_std_test_attr_macro() {
+    check(
+        r#"
+//- proc_macros: identity
+use proc_macros::identity as test;
+
+#[test]
+fn foo() {
+    $0
+}
+    "#,
+        expect![[r#"
+            fn foo()  fn()
+            md proc_macros
+            bt u32     u32
+            kw async
+            kw const
+            kw crate::
+            kw enum
+            kw extern
+            kw false
+            kw fn
+            kw for
+            kw if
+            kw if let
+            kw impl
+            kw let
+            kw loop
+            kw match
+            kw mod
+            kw return
+            kw self::
+            kw static
+            kw struct
+            kw trait
+            kw true
+            kw type
+            kw union
+            kw unsafe
+            kw use
+            kw while
+            kw while let
+            sn macro_rules
+            sn pd
+            sn ppd
+        "#]],
+    );
+}
-- 
cgit 1.4.1-3-g733a5