Stripping trailing commas and spaces from vec! elements (#1219)

* Stripping trailing commas and spaces from `vec!` elements

* Stripping trailing commas and spaces ONLY from `vec!` elements

* Added comment

src/macros.rs

@@ -114,7 +114,12 @@ pub fn rewrite_macro(mac: &ast::Mac,
             parser.bump();
 
             if parser.token == Token::Eof {
-                return None;
+                // vec! is a special case of bracket macro which should be formated as an array.
+                if macro_name == "vec!" {
+                    break;
+                } else {
+                    return None;
+                }
             }
         }
     }

tests/source/macros.rs

@@ -28,6 +28,15 @@ fn main() {
 
     vec! [a /* comment */];
 
+    // Trailing spaces after a comma
+    vec![
+    a,   
+    ];
+    
+    unknown_bracket_macro__comma_should_not_be_stripped![
+    a,
+    ];
+    
     foo(makro!(1,   3));
 
     hamkaas!{ () };

tests/target/macros.rs

@@ -34,6 +34,13 @@ fn main() {
 
     vec![a /* comment */];
 
+    // Trailing spaces after a comma
+    vec![a];
+
+    unknown_bracket_macro__comma_should_not_be_stripped![
+    a,
+    ];
+
     foo(makro!(1, 3));
 
     hamkaas!{ () };