Merge pull request #2413 from flip1995/assign_ops
Improved suggestion on misrefactored_assign_op lint
This commit is contained in:
Oliver Schneider
GitHub
commit
ee8d32850d
3 changed files with 154 additions and 31 deletions
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@ -1,4 +1,5 @@
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use rustc::hir;
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use rustc::hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
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use rustc::lint::*;
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use syntax::ast;
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use utils::{get_trait_def_id, implements_trait, snippet_opt, span_lint_and_then, SpanlessEq};
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@ -87,19 +88,29 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for AssignOps {
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});
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if let hir::ExprBinary(binop, ref l, ref r) = rhs.node {
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if op.node == binop.node {
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let lint = |assignee: &hir::Expr, rhs: &hir::Expr| {
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let lint = |assignee: &hir::Expr, rhs_other: &hir::Expr| {
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span_lint_and_then(
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cx,
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MISREFACTORED_ASSIGN_OP,
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expr.span,
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"variable appears on both sides of an assignment operation",
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|db| if let (Some(snip_a), Some(snip_r)) =
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(snippet_opt(cx, assignee.span), snippet_opt(cx, rhs.span))
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(snippet_opt(cx, assignee.span), snippet_opt(cx, rhs_other.span))
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{
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let a = &sugg::Sugg::hir(cx, assignee, "..");
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let r = &sugg::Sugg::hir(cx, rhs, "..");
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let long = format!("{} = {}", snip_a, sugg::make_binop(higher::binop(op.node), a, r));
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db.span_suggestion(
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expr.span,
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"replace it with",
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format!("{} {}= {}", snip_a, op.node.as_str(), snip_r),
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&format!("Did you mean {} = {} {} {} or {}? Consider replacing it with",
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snip_a, snip_a, op.node.as_str(), snip_r,
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long),
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format!("{} {}= {}", snip_a, op.node.as_str(), snip_r)
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);
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db.span_suggestion(
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expr.span,
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"or",
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long
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);
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},
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);
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@ -189,23 +200,34 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for AssignOps {
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);
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}
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};
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// a = a op b
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if SpanlessEq::new(cx).ignore_fn().eq_expr(assignee, l) {
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lint(assignee, r);
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}
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// a = b commutative_op a
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if SpanlessEq::new(cx).ignore_fn().eq_expr(assignee, r) {
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match op.node {
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hir::BiAdd |
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hir::BiMul |
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hir::BiAnd |
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hir::BiOr |
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hir::BiBitXor |
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hir::BiBitAnd |
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hir::BiBitOr => {
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lint(assignee, l);
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},
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_ => {},
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let mut visitor = ExprVisitor {
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assignee: assignee,
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counter: 0,
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cx: cx
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};
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walk_expr(&mut visitor, e);
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if visitor.counter == 1 {
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// a = a op b
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if SpanlessEq::new(cx).ignore_fn().eq_expr(assignee, l) {
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lint(assignee, r);
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}
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// a = b commutative_op a
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if SpanlessEq::new(cx).ignore_fn().eq_expr(assignee, r) {
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match op.node {
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hir::BiAdd |
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hir::BiMul |
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hir::BiAnd |
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hir::BiOr |
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hir::BiBitXor |
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hir::BiBitAnd |
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hir::BiBitOr => {
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lint(assignee, l);
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},
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_ => {},
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}
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}
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}
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}
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@ -222,3 +244,22 @@ fn is_commutative(op: hir::BinOp_) -> bool {
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BiSub | BiDiv | BiRem | BiShl | BiShr | BiLt | BiLe | BiGe | BiGt => false,
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}
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}
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struct ExprVisitor<'a, 'tcx: 'a> {
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assignee: &'a hir::Expr,
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counter: u8,
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cx: &'a LateContext<'a, 'tcx>,
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}
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impl<'a, 'tcx: 'a> Visitor<'tcx> for ExprVisitor<'a, 'tcx> {
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fn visit_expr(&mut self, expr: &'tcx hir::Expr) {
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if SpanlessEq::new(self.cx).ignore_fn().eq_expr(self.assignee, &expr) {
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self.counter += 1;
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}
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walk_expr(self, expr);
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}
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fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
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NestedVisitorMap::None
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}
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}
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@ -2,7 +2,7 @@
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#[allow(unused_assignments)]
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#[warn(misrefactored_assign_op)]
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#[warn(misrefactored_assign_op, assign_op_pattern)]
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fn main() {
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let mut a = 5;
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a += a + 1;
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@ -13,6 +13,10 @@ fn main() {
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a /= a / 2;
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a %= a % 5;
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a &= a & 1;
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a *= a * a;
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a = a * a * a;
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a = a * 42 * a;
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a = a * 2 + a;
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a -= 1 - a;
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a /= 5 / a;
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a %= 42 % a;
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@ -2,51 +2,129 @@ error: variable appears on both sides of an assignment operation
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--> $DIR/assign_ops2.rs:8:5
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8 | a += a + 1;
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| ^^^^^^^^^^ help: replace it with: `a += 1`
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| ^^^^^^^^^^
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= note: `-D misrefactored-assign-op` implied by `-D warnings`
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help: Did you mean a = a + 1 or a = a + a + 1? Consider replacing it with
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8 | a += 1;
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| ^^^^^^
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help: or
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8 | a = a + a + 1;
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| ^^^^^^^^^^^^^
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error: variable appears on both sides of an assignment operation
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--> $DIR/assign_ops2.rs:9:5
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9 | a += 1 + a;
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| ^^^^^^^^^^ help: replace it with: `a += 1`
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| ^^^^^^^^^^
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help: Did you mean a = a + 1 or a = a + 1 + a? Consider replacing it with
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9 | a += 1;
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| ^^^^^^
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help: or
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9 | a = a + 1 + a;
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| ^^^^^^^^^^^^^
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error: variable appears on both sides of an assignment operation
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--> $DIR/assign_ops2.rs:10:5
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10 | a -= a - 1;
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| ^^^^^^^^^^ help: replace it with: `a -= 1`
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| ^^^^^^^^^^
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help: Did you mean a = a - 1 or a = a - (a - 1)? Consider replacing it with
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10 | a -= 1;
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| ^^^^^^
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help: or
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10 | a = a - (a - 1);
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| ^^^^^^^^^^^^^^^
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error: variable appears on both sides of an assignment operation
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--> $DIR/assign_ops2.rs:11:5
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11 | a *= a * 99;
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| ^^^^^^^^^^^ help: replace it with: `a *= 99`
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| ^^^^^^^^^^^
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help: Did you mean a = a * 99 or a = a * a * 99? Consider replacing it with
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11 | a *= 99;
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| ^^^^^^^
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help: or
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11 | a = a * a * 99;
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| ^^^^^^^^^^^^^^
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error: variable appears on both sides of an assignment operation
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--> $DIR/assign_ops2.rs:12:5
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12 | a *= 42 * a;
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| ^^^^^^^^^^^ help: replace it with: `a *= 42`
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| ^^^^^^^^^^^
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help: Did you mean a = a * 42 or a = a * 42 * a? Consider replacing it with
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12 | a *= 42;
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| ^^^^^^^
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help: or
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12 | a = a * 42 * a;
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| ^^^^^^^^^^^^^^
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error: variable appears on both sides of an assignment operation
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--> $DIR/assign_ops2.rs:13:5
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13 | a /= a / 2;
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| ^^^^^^^^^^ help: replace it with: `a /= 2`
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| ^^^^^^^^^^
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help: Did you mean a = a / 2 or a = a / (a / 2)? Consider replacing it with
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13 | a /= 2;
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| ^^^^^^
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help: or
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13 | a = a / (a / 2);
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| ^^^^^^^^^^^^^^^
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error: variable appears on both sides of an assignment operation
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--> $DIR/assign_ops2.rs:14:5
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14 | a %= a % 5;
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| ^^^^^^^^^^ help: replace it with: `a %= 5`
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| ^^^^^^^^^^
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help: Did you mean a = a % 5 or a = a % (a % 5)? Consider replacing it with
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14 | a %= 5;
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| ^^^^^^
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help: or
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14 | a = a % (a % 5);
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| ^^^^^^^^^^^^^^^
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error: variable appears on both sides of an assignment operation
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--> $DIR/assign_ops2.rs:15:5
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15 | a &= a & 1;
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| ^^^^^^^^^^ help: replace it with: `a &= 1`
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| ^^^^^^^^^^
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help: Did you mean a = a & 1 or a = a & a & 1? Consider replacing it with
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15 | a &= 1;
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| ^^^^^^
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help: or
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15 | a = a & a & 1;
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| ^^^^^^^^^^^^^
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error: aborting due to 8 previous errors
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error: variable appears on both sides of an assignment operation
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--> $DIR/assign_ops2.rs:16:5
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16 | a *= a * a;
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| ^^^^^^^^^^
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help: Did you mean a = a * a or a = a * a * a? Consider replacing it with
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16 | a *= a;
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| ^^^^^^
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help: or
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16 | a = a * a * a;
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| ^^^^^^^^^^^^^
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error: aborting due to 9 previous errors
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