From 157544394997788385b00c9f031b1b30ca1065da Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Fri, 8 Dec 2023 18:42:04 -0800
Subject: [PATCH] Add test of automatic parenthesization of braced structs in
 cond

---
 Cargo.toml    |  7 +++++--
 tests/test.rs | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 2 deletions(-)
 create mode 100644 tests/test.rs

diff --git a/Cargo.toml b/Cargo.toml
index 2832b86..e942ea9 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -19,10 +19,13 @@ verbatim = ["syn/parsing"]
 
 [dependencies]
 proc-macro2 = { version = "1.0.63", default-features = false }
-syn = { version = "2.0.31", default-features = false, features = ["full"] }
+syn = { version = "2.0.40", default-features = false, features = ["full"] }
 
 [dev-dependencies]
-syn = { version = "2.0.31", default-features = false, features = ["parsing"] }
+indoc = "2"
+proc-macro2 = { version = "1", default-features = false }
+quote = { version = "1", default-features = false }
+syn = { version = "2.0.40", default-features = false, features = ["parsing"] }
 
 [lib]
 doc-scrape-examples = false
diff --git a/tests/test.rs b/tests/test.rs
new file mode 100644
index 0000000..c9d155e
--- /dev/null
+++ b/tests/test.rs
@@ -0,0 +1,34 @@
+use indoc::indoc;
+use proc_macro2::{Delimiter, Group, TokenStream};
+use quote::quote;
+
+#[track_caller]
+fn test(tokens: TokenStream, expected: &str) {
+    let syntax_tree: syn::File = syn::parse2(tokens).unwrap();
+    let pretty = prettyplease::unparse(&syntax_tree);
+    assert_eq!(pretty, expected);
+}
+
+#[test]
+fn test_parenthesize_cond() {
+    let s = Group::new(Delimiter::None, quote!(Struct {}));
+    test(
+        quote! {
+            fn main() {
+                if #s == #s {}
+            }
+        },
+        // FIXME this is not valid Rust syntax. It needs to be either:
+        //
+        //     if (Struct {}) == (Struct {}) {}
+        //
+        // or:
+        //
+        //     if (Struct {} == Struct {}) {}
+        indoc! {"
+            fn main() {
+                if Struct {} == Struct {} {}
+            }
+        "},
+    );
+}