head expression => scrutinee

src/librustc/hir/intravisit.rs

@@ -1011,22 +1011,22 @@ pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr) {
             visitor.visit_expr(subexpression);
             visitor.visit_ty(typ)
         }
-        ExprKind::If(ref head_expression, ref if_block, ref optional_else) => {
-            visitor.visit_expr(head_expression);
+        ExprKind::If(ref scrutinee, ref if_block, ref optional_else) => {
+            visitor.visit_expr(scrutinee);
             visitor.visit_expr(if_block);
             walk_list!(visitor, visit_expr, optional_else);
         }
-        ExprKind::While(ref subexpression, ref block, ref opt_label) => {
+        ExprKind::While(ref scrutinee, ref block, ref opt_label) => {
             walk_list!(visitor, visit_label, opt_label);
-            visitor.visit_expr(subexpression);
+            visitor.visit_expr(scrutinee);
             visitor.visit_block(block);
         }
         ExprKind::Loop(ref block, ref opt_label, _) => {
             walk_list!(visitor, visit_label, opt_label);
             visitor.visit_block(block);
         }
-        ExprKind::Match(ref subexpression, ref arms, _) => {
-            visitor.visit_expr(subexpression);
+        ExprKind::Match(ref scrutinee, ref arms, _) => {
+            visitor.visit_expr(scrutinee);
             walk_list!(visitor, visit_arm, arms);
         }
         ExprKind::Closure(_, ref function_declaration, body, _fn_decl_span, _gen) => {

src/librustc_lint/unused.rs

@@ -355,10 +355,10 @@ impl EarlyLintPass for UnusedParens {
         let (value, msg, followed_by_block) = match e.node {
             If(ref cond, ..) => (cond, "`if` condition", true),
             While(ref cond, ..) => (cond, "`while` condition", true),
-            IfLet(_, ref cond, ..) => (cond, "`if let` head expression", true),
-            WhileLet(_, ref cond, ..) => (cond, "`while let` head expression", true),
-            ForLoop(_, ref cond, ..) => (cond, "`for` head expression", true),
-            Match(ref head, _) => (head, "`match` head expression", true),
+            IfLet(_, ref cond, ..) => (cond, "`if let` scrutinee", true),
+            WhileLet(_, ref cond, ..) => (cond, "`while let` scrutinee", true),
+            ForLoop(_, ref cond, ..) => (cond, "`for` scrutinee", true),
+            Match(ref head, _) => (head, "`match` scrutinee", true),
             Ret(Some(ref value)) => (value, "`return` value", false),
             Assign(_, ref value) => (value, "assigned value", false),
             AssignOp(.., ref value) => (value, "assigned value", false),

src/test/ui/lint/lint-unnecessary-parens.rs

@@ -19,11 +19,11 @@ fn main() {
 
     if (true) {} //~ ERROR unnecessary parentheses around `if` condition
     while (true) {} //~ ERROR unnecessary parentheses around `while` condition
-    match (true) { //~ ERROR unnecessary parentheses around `match` head expression
+    match (true) { //~ ERROR unnecessary parentheses around `match` scrutinee
         _ => {}
     }
-    if let 1 = (1) {} //~ ERROR unnecessary parentheses around `if let` head expression
-    while let 1 = (2) {} //~ ERROR unnecessary parentheses around `while let` head expression
+    if let 1 = (1) {} //~ ERROR unnecessary parentheses around `if let` scrutinee
+    while let 1 = (2) {} //~ ERROR unnecessary parentheses around `while let` scrutinee
     let v = X { y: false };
     // struct lits needs parens, so these shouldn't warn.
     if (v == X { y: true }) {}

src/test/ui/lint/lint-unnecessary-parens.stderr

@@ -34,19 +34,19 @@ error: unnecessary parentheses around `while` condition
 LL |     while (true) {}
    |           ^^^^^^ help: remove these parentheses
 
-error: unnecessary parentheses around `match` head expression
+error: unnecessary parentheses around `match` scrutinee
   --> $DIR/lint-unnecessary-parens.rs:22:11
    |
 LL |     match (true) {
    |           ^^^^^^ help: remove these parentheses
 
-error: unnecessary parentheses around `if let` head expression
+error: unnecessary parentheses around `if let` scrutinee
   --> $DIR/lint-unnecessary-parens.rs:25:16
    |
 LL |     if let 1 = (1) {}
    |                ^^^ help: remove these parentheses
 
-error: unnecessary parentheses around `while let` head expression
+error: unnecessary parentheses around `while let` scrutinee
   --> $DIR/lint-unnecessary-parens.rs:26:19
    |
 LL |     while let 1 = (2) {}