Fix formatting of binding patterns

This ensures that `inko fmt` doesn't remove the explicit type annotation
and `mut` modifier when formatting binding patterns.

This fixes #762.

Changelog: fixed

compiler/src/format.rs

@@ -2045,6 +2045,7 @@ impl Document {
             nodes::Pattern::Or(_)
                 | nodes::Pattern::Class(_)
                 | nodes::Pattern::Tuple(_)
+                | nodes::Pattern::Identifier(_)
         ) || node.guard.is_some()
         {
             Node::HardLine
@@ -2138,7 +2139,22 @@ impl Document {
             nodes::Pattern::Int(n) => vec![Node::text(&n.value)],
             nodes::Pattern::True(_) => vec![Node::text("true")],
             nodes::Pattern::False(_) => vec![Node::text("false")],
-            nodes::Pattern::Identifier(n) => vec![Node::text(&n.name.name)],
+            nodes::Pattern::Identifier(n) => {
+                let mut nodes = Vec::new();
+
+                if n.mutable {
+                    nodes.push(Node::text("mut "));
+                }
+
+                nodes.push(Node::text(&n.name.name));
+
+                if let Some(typ) = &n.value_type {
+                    nodes.push(Node::text(": "));
+                    nodes.push(self.type_reference(typ));
+                }
+
+                vec![self.group(nodes)]
+            }
             nodes::Pattern::Tuple(n) => {
                 let gid = self.new_group_id();
                 let vals = self.list(&n.values, gid, |s, n| s.pattern(n));

std/fixtures/fmt/binding_pattern/input.inko

@@ -0,0 +1,29 @@
+fn example1 {
+  match (10, 20) {
+    case (a: Int, b: Int) -> {}
+  }
+}
+
+fn example2 {
+  match 42 {
+    case mut a -> {}
+  }
+}
+
+fn example3 {
+  match 42 {
+    case mut loooooooooooooooooooooooooong_naaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaameeeeeeeeee -> {}
+  }
+}
+
+fn example4 {
+  match 42 {
+    case mut loooooooooooooooooooooooooong_naaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaameeeeeeeeee: TypeNameHere -> {}
+  }
+}
+
+fn example5 {
+  match 42 {
+    case mut loooooooooooooooooooooooooong_naaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaameeeeeeeeee: TypeNameHere if true -> {}
+  }
+}

std/fixtures/fmt/binding_pattern/output.inko

@@ -0,0 +1,36 @@
+fn example1 {
+  match (10, 20) {
+    case (a: Int, b: Int) -> {}
+  }
+}
+
+fn example2 {
+  match 42 {
+    case mut a -> {}
+  }
+}
+
+fn example3 {
+  match 42 {
+    case
+      mut loooooooooooooooooooooooooong_naaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaameeeeeeeeee
+    -> {}
+  }
+}
+
+fn example4 {
+  match 42 {
+    case
+      mut loooooooooooooooooooooooooong_naaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaameeeeeeeeee: TypeNameHere
+    -> {}
+  }
+}
+
+fn example5 {
+  match 42 {
+    case
+      mut loooooooooooooooooooooooooong_naaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaameeeeeeeeee: TypeNameHere
+    if true
+    -> {}
+  }
+}