Merge pull request #117 from dtolnay/binaryattr

Insert parentheses around binary operation with attribute

Author: dtolnay

src/expr.rs

@@ -211,10 +211,16 @@ impl Printer {
 
         self.outer_attrs(&expr.attrs);
         self.ibox(0);
+        if !expr.attrs.is_empty() {
+            self.word("(");
+        }
         self.subexpr(&expr.left, left_prec <= Precedence::Range, left_fixup);
         self.word(" = ");
         self.neverbreak();
         self.expr(&expr.right, right_fixup);
+        if !expr.attrs.is_empty() {
+            self.word(")");
+        }
         self.end();
     }
 
@@ -292,12 +298,18 @@ impl Printer {
         self.outer_attrs(&expr.attrs);
         self.ibox(INDENT);
         self.ibox(-INDENT);
+        if !expr.attrs.is_empty() {
+            self.word("(");
+        }
         self.subexpr(&expr.left, left_needs_group, left_fixup);
         self.end();
         self.space();
         self.binary_operator(&expr.op);
         self.nbsp();
         self.subexpr(&expr.right, right_needs_group, right_fixup);
+        if !expr.attrs.is_empty() {
+            self.word(")");
+        }
         self.end();
     }
 
@@ -375,11 +387,17 @@ impl Printer {
         self.outer_attrs(&expr.attrs);
         self.ibox(INDENT);
         self.ibox(-INDENT);
+        if !expr.attrs.is_empty() {
+            self.word("(");
+        }
         self.subexpr(&expr.expr, left_prec < Precedence::Cast, left_fixup);
         self.end();
         self.space();
         self.word("as ");
         self.ty(&expr.ty);
+        if !expr.attrs.is_empty() {
+            self.word(")");
+        }
         self.end();
     }
 

src/fixup.rs

@@ -421,7 +421,7 @@ fn scan_right(
     }
     match expr {
         #![cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
-        Expr::Assign(e) => {
+        Expr::Assign(e) if e.attrs.is_empty() => {
             if match fixup.next_operator {
                 Precedence::Unambiguous => fail_offset >= 2,
                 _ => bailout_offset >= 1,
@@ -447,7 +447,7 @@ fn scan_right(
                 Scan::Bailout
             }
         }
-        Expr::Binary(e) => {
+        Expr::Binary(e) if e.attrs.is_empty() => {
             if match fixup.next_operator {
                 Precedence::Unambiguous => {
                     fail_offset >= 2
@@ -628,8 +628,10 @@ fn scan_right(
         }
         Expr::Group(e) => scan_right(&e.expr, fixup, precedence, fail_offset, bailout_offset),
         Expr::Array(_)
+        | Expr::Assign(_)
         | Expr::Async(_)
         | Expr::Await(_)
+        | Expr::Binary(_)
         | Expr::Block(_)
         | Expr::Call(_)
         | Expr::Cast(_)