chore: add member access formatter (#3109)

Author: jonybur

tooling/nargo_fmt/src/visitor/expr.rs

@@ -39,6 +39,10 @@ impl FmtVisitor<'_> {
                     self.format_expr(infix.rhs)
                 )
             }
+            ExpressionKind::MemberAccess(member_access_expr) => {
+                let lhs_str = self.format_expr(member_access_expr.lhs);
+                format!("{}.{}", lhs_str, member_access_expr.rhs)
+            }
             ExpressionKind::Index(index_expr) => {
                 let formatted_collection =
                     self.format_expr(index_expr.collection).trim_end().to_string();

tooling/nargo_fmt/tests/expected/member_access.nr

@@ -0,0 +1,15 @@
+struct Address {
+    city: String,
+    country: String,
+}
+
+struct Person {
+    name: String,
+    age: u8,
+    address: Address,
+}
+
+fn foo(p: Person) {
+    p.name;
+    p.address.country;
+}

tooling/nargo_fmt/tests/input/member_access.nr

@@ -0,0 +1,15 @@
+struct Address {
+    city: String,
+    country: String,
+}
+
+struct Person {
+    name: String,
+    age: u8,
+    address: Address,
+}
+
+fn foo(p: Person) {
+    p   .   name;
+    p.address   .   country;
+}