Merge pull request #63 from dtolnay/structcond

Add test of automatic parenthesization of braced structs in cond

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

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 {} {}
+            }
+        "},
+    );
+}