Auto merge of #3680 - g-bartoszek:needless-bool-else-if-brackets, r=oli-obk

needless bool lint suggestion is wrapped in brackets if it is an "els…

…e" clause of an "if-else" statement
This commit is contained in:
bors 2019-01-21 11:47:06 +00:00
commit 54978a571c
3 changed files with 43 additions and 2 deletions

View file

@ -72,12 +72,16 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NeedlessBool {
let snip = Sugg::hir_with_applicability(cx, pred, "<predicate>", &mut applicability);
let snip = if not { !snip } else { snip };
let hint = if ret {
let mut hint = if ret {
format!("return {}", snip)
} else {
snip.to_string()
};
if parent_node_is_if_expr(&e, &cx) {
hint = format!("{{ {} }}", hint);
}
span_lint_and_sugg(
cx,
NEEDLESS_BOOL,
@ -119,6 +123,19 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NeedlessBool {
}
}
fn parent_node_is_if_expr<'a, 'b>(expr: &Expr, cx: &LateContext<'a, 'b>) -> bool {
let parent_id = cx.tcx.hir().get_parent_node(expr.id);
let parent_node = cx.tcx.hir().get(parent_id);
if let rustc::hir::Node::Expr(e) = parent_node {
if let ExprKind::If(_, _, _) = e.node {
return true;
}
}
false
}
#[derive(Copy, Clone)]
pub struct BoolComparison;

View file

@ -141,3 +141,16 @@ fn needless_bool3(x: bool) {
if x == true {};
if x == false {};
}
fn needless_bool_in_the_suggestion_wraps_the_predicate_of_if_else_statement_in_brackets() {
let b = false;
let returns_bool = || false;
let x = if b {
true
} else if returns_bool() {
false
} else {
true
};
}

View file

@ -136,5 +136,16 @@ error: equality checks against false can be replaced by a negation
LL | if x == false {};
| ^^^^^^^^^^ help: try simplifying it as shown: `!x`
error: aborting due to 15 previous errors
error: this if-then-else expression returns a bool literal
--> $DIR/needless_bool.rs:151:12
|
LL | } else if returns_bool() {
| ____________^
LL | | false
LL | | } else {
LL | | true
LL | | };
| |_____^ help: you can reduce it to: `{ !returns_bool() }`
error: aborting due to 16 previous errors