From 58dfeba043f7764d31556cacb031b61ecac32312 Mon Sep 17 00:00:00 2001
From: Folkert <folkert@folkertdev.nl>
Date: Sun, 5 Jul 2020 18:34:28 +0200
Subject: [PATCH] accept a newline and body when patterns are different

---
 compiler/can/src/def.rs                    |  6 +++++-
 compiler/region/src/all.rs                 | 11 +++++++++++
 compiler/reporting/tests/test_reporting.rs | 16 ++++++++++++++++
 3 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/compiler/can/src/def.rs b/compiler/can/src/def.rs
index 902f18bad3..fd3c0d010f 100644
--- a/compiler/can/src/def.rs
+++ b/compiler/can/src/def.rs
@@ -151,7 +151,7 @@ pub fn canonicalize_defs<'a>(
                 match iter.peek() {
                     Some(Located {
                         value: Body(body_pattern, body_expr),
-                        ..
+                        region: body_region,
                     }) => {
                         if pattern.value.equivalent(&body_pattern.value) {
                             iter.next();
@@ -165,6 +165,10 @@ pub fn canonicalize_defs<'a>(
                                 &mut scope,
                                 pattern_type,
                             )
+                        } else if loc_def.region.lines_between(body_region) > 1 {
+                            // there is a line of whitespace between the annotation and the body
+                            // treat annotation and body separately
+                            to_pending_def(env, var_store, &loc_def.value, &mut scope, pattern_type)
                         } else {
                             // the pattern of the annotation does not match the pattern of the body directly below it
                             env.problems.push(Problem::SignatureDefMismatch {
diff --git a/compiler/region/src/all.rs b/compiler/region/src/all.rs
index 372f503ea0..08230b4729 100644
--- a/compiler/region/src/all.rs
+++ b/compiler/region/src/all.rs
@@ -78,6 +78,17 @@ impl Region {
             Self::zero()
         }
     }
+
+    pub fn lines_between(&self, other: &Region) -> u32 {
+        if self.end_line <= other.start_line {
+            other.start_line - self.end_line
+        } else if self.start_line >= other.end_line {
+            self.start_line - other.end_line
+        } else {
+            // intersection
+            0
+        }
+    }
 }
 
 #[test]
diff --git a/compiler/reporting/tests/test_reporting.rs b/compiler/reporting/tests/test_reporting.rs
index 63fc5c0731..58fd8a2fb7 100644
--- a/compiler/reporting/tests/test_reporting.rs
+++ b/compiler/reporting/tests/test_reporting.rs
@@ -2839,6 +2839,22 @@ mod test_reporting {
         )
     }
 
+    #[test]
+    fn annotation_newline_body_is_fine() {
+        report_problem_as(
+            indoc!(
+                r#"
+                bar : Int
+
+                foo = \x -> x
+
+                foo bar
+                "#
+            ),
+            indoc!(""),
+        )
+    }
+
     #[test]
     fn invalid_alias_rigid_var_pattern() {
         report_problem_as(