From 41372631ff7a9dc352c4765b08847757a5f7d590 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Esteban=20K=C3=BCber?= <esteban@kuber.com.ar>
Date: Wed, 13 Nov 2019 14:45:52 -0800
Subject: [PATCH] Fix ICE when trying to suggest `Type<>` instead of `Type()`

---
 src/librustc/hir/lowering.rs | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/src/librustc/hir/lowering.rs b/src/librustc/hir/lowering.rs
index 2c8e14f2addff..15039cc3cdff2 100644
--- a/src/librustc/hir/lowering.rs
+++ b/src/librustc/hir/lowering.rs
@@ -1860,15 +1860,16 @@ impl<'a> LoweringContext<'a> {
                         if let Ok(snippet) = self.sess.source_map().span_to_snippet(data.span) {
                             // Do not suggest going from `Trait()` to `Trait<>`
                             if data.inputs.len() > 0 {
-                                let split = snippet.find('(').unwrap();
-                                let trait_name = &snippet[0..split];
-                                let args = &snippet[split + 1 .. snippet.len() - 1];
-                                err.span_suggestion(
-                                    data.span,
-                                    "use angle brackets instead",
-                                    format!("{}<{}>", trait_name, args),
-                                    Applicability::MaybeIncorrect,
-                                );
+                                if let Some(split) = snippet.find('(') {
+                                    let trait_name = &snippet[0..split];
+                                    let args = &snippet[split + 1 .. snippet.len() - 1];
+                                    err.span_suggestion(
+                                        data.span,
+                                        "use angle brackets instead",
+                                        format!("{}<{}>", trait_name, args),
+                                        Applicability::MaybeIncorrect,
+                                    );
+                                }
                             }
                         };
                         err.emit();