Squash closures and jumps into a single precedence level

Author: dtolnay

compiler/rustc_ast/src/ast.rs

@@ -1317,9 +1317,8 @@ impl Expr {
 
     pub fn precedence(&self) -> ExprPrecedence {
         match self.kind {
-            ExprKind::Closure(..) => ExprPrecedence::Closure,
-
             ExprKind::Break(..)
+            | ExprKind::Closure(..)
             | ExprKind::Continue(..)
             | ExprKind::Ret(..)
             | ExprKind::Yield(..)

compiler/rustc_ast/src/util/parser.rs

@@ -231,8 +231,7 @@ impl AssocOp {
 
 #[derive(Clone, Copy, PartialEq, PartialOrd)]
 pub enum ExprPrecedence {
-    Closure,
-    // return, break, yield
+    // return, break, yield, closures
     Jump,
     // = += -= *= /= %= &= |= ^= <<= >>=
     Assign,

compiler/rustc_hir/src/hir.rs

@@ -1697,9 +1697,8 @@ pub struct Expr<'hir> {
 impl Expr<'_> {
     pub fn precedence(&self) -> ExprPrecedence {
         match self.kind {
-            ExprKind::Closure { .. } => ExprPrecedence::Closure,
-
             ExprKind::Break(..)
+            | ExprKind::Closure { .. }
             | ExprKind::Continue(..)
             | ExprKind::Ret(..)
             | ExprKind::Yield(..)

tests/ui-fulldeps/pprust-parenthesis-insertion.rs

@@ -72,7 +72,7 @@ static EXPRS: &[&str] = &[
     "(return) - 2",
     // Closures and jumps have equal precedence.
     "|| return break 2",
-    "return break (|| 2)", // FIXME: no parenthesis needed.
+    "return break || 2",
     // These mean different things.
     "if let _ = true && false {}",
     "if let _ = (true && false) {}",