From a72613be50f8afa39c2d46f732252463dc9cc14f Mon Sep 17 00:00:00 2001
From: Catherine <114838443+Centri3@users.noreply.github.com>
Date: Tue, 18 Jul 2023 09:41:56 -0500
Subject: [PATCH] Add parenthesis around closure method call

---
 src/chains.rs              | 25 ++++++++++++++++++++-----
 tests/source/issue-4808.rs | 13 +++++++++++++
 tests/target/issue-4808.rs | 13 +++++++++++++
 3 files changed, 46 insertions(+), 5 deletions(-)
 create mode 100644 tests/source/issue-4808.rs
 create mode 100644 tests/target/issue-4808.rs

diff --git a/src/chains.rs b/src/chains.rs
index bf09d817ed1..d4876389c86 100644
--- a/src/chains.rs
+++ b/src/chains.rs
@@ -253,11 +253,7 @@ impl ChainItemKind {
                 return (
                     ChainItemKind::Parent {
                         expr: expr.clone(),
-                        parens: is_method_call_receiver
-                            && matches!(
-                                &expr.kind,
-                                ast::ExprKind::Lit(lit) if crate::expr::lit_ends_in_dot(lit)
-                            ),
+                        parens: is_method_call_receiver && should_add_parens(expr),
                     },
                     expr.span,
                 );
@@ -982,3 +978,22 @@ fn trim_tries(s: &str) -> String {
     }
     result
 }
+
+/// Whether a method call's receiver needs parenthesis, like
+/// ```rust,ignore
+/// || .. .method();
+/// || 1.. .method();
+/// 1. .method();
+/// ```
+/// Which all need parenthesis or a space before `.method()`.
+fn should_add_parens(expr: &ast::Expr) -> bool {
+    match expr.kind {
+        ast::ExprKind::Lit(ref lit) => crate::expr::lit_ends_in_dot(lit),
+        ast::ExprKind::Closure(ref cl) => match cl.body.kind {
+            ast::ExprKind::Range(_, _, ast::RangeLimits::HalfOpen) => true,
+            ast::ExprKind::Lit(ref lit) => crate::expr::lit_ends_in_dot(lit),
+            _ => false,
+        },
+        _ => false,
+    }
+}
diff --git a/tests/source/issue-4808.rs b/tests/source/issue-4808.rs
new file mode 100644
index 00000000000..93076edcdce
--- /dev/null
+++ b/tests/source/issue-4808.rs
@@ -0,0 +1,13 @@
+trait Trait {
+    fn method(&self) {}
+}
+
+impl<F: Fn() -> T, T> Trait for F {}
+
+impl Trait for f32 {}
+
+fn main() {
+    || 10. .method();
+    || .. .method();
+    || 1.. .method();
+}
diff --git a/tests/target/issue-4808.rs b/tests/target/issue-4808.rs
new file mode 100644
index 00000000000..cdef53a1bfc
--- /dev/null
+++ b/tests/target/issue-4808.rs
@@ -0,0 +1,13 @@
+trait Trait {
+    fn method(&self) {}
+}
+
+impl<F: Fn() -> T, T> Trait for F {}
+
+impl Trait for f32 {}
+
+fn main() {
+    || (10.).method();
+    (|| ..).method();
+    (|| 1..).method();
+}