use rustc::lint::*;
+use rustc::{declare_lint, lint_array};
+use if_chain::if_chain;
use rustc::hir;
use rustc::hir::BindingAnnotation;
use rustc::hir::def::Def;
use syntax::ast;
-use utils::{snippet, span_lint_and_then};
+use crate::utils::{snippet, span_lint_and_then};
/// **What it does:** Checks for variable declarations immediately followed by a
/// conditional affectation.
/// None
/// };
/// ```
-declare_lint! {
+declare_clippy_lint! {
pub USELESS_LET_IF_SEQ,
- Warn,
+ style,
"unidiomatic `let mut` declaration followed by initialization in `if`"
}
while let Some(stmt) = it.next() {
if_chain! {
if let Some(expr) = it.peek();
- if let hir::StmtDecl(ref decl, _) = stmt.node;
- if let hir::DeclLocal(ref decl) = decl.node;
- if let hir::PatKind::Binding(mode, canonical_id, ref name, None) = decl.pat.node;
- if let hir::StmtExpr(ref if_, _) = expr.node;
- if let hir::ExprIf(ref cond, ref then, ref else_) = if_.node;
+ if let hir::StmtKind::Decl(ref decl, _) = stmt.node;
+ if let hir::DeclKind::Local(ref decl) = decl.node;
+ if let hir::PatKind::Binding(mode, canonical_id, ident, None) = decl.pat.node;
+ if let hir::StmtKind::Expr(ref if_, _) = expr.node;
+ if let hir::ExprKind::If(ref cond, ref then, ref else_) = if_.node;
if !used_in_expr(cx, canonical_id, cond);
- if let hir::ExprBlock(ref then) = then.node;
+ if let hir::ExprKind::Block(ref then, _) = then.node;
if let Some(value) = check_assign(cx, canonical_id, &*then);
if !used_in_expr(cx, canonical_id, value);
then {
let span = stmt.span.to(if_.span);
-
+
let (default_multi_stmts, default) = if let Some(ref else_) = *else_ {
- if let hir::ExprBlock(ref else_) = else_.node {
+ if let hir::ExprKind::Block(ref else_, _) = else_.node {
if let Some(default) = check_assign(cx, canonical_id, else_) {
(else_.stmts.len() > 1, default)
} else if let Some(ref default) = decl.init {
} else {
continue;
};
-
+
let mutability = match mode {
BindingAnnotation::RefMut | BindingAnnotation::Mutable => "<mut> ",
_ => "",
};
-
+
// FIXME: this should not suggest `mut` if we can detect that the variable is not
// use mutably after the `if`
-
+
let sug = format!(
"let {mut}{name} = if {cond} {{{then} {value} }} else {{{else} {default} }};",
mut=mutability,
- name=name.node,
+ name=ident.name,
cond=snippet(cx, cond.span, "_"),
then=if then.stmts.len() > 1 { " ..;" } else { "" },
else=if default_multi_stmts { " ..;" } else { "" },
impl<'a, 'tcx> hir::intravisit::Visitor<'tcx> for UsedVisitor<'a, 'tcx> {
fn visit_expr(&mut self, expr: &'tcx hir::Expr) {
if_chain! {
- if let hir::ExprPath(ref qpath) = expr.node;
+ if let hir::ExprKind::Path(ref qpath) = expr.node;
if let Def::Local(local_id) = self.cx.tables.qpath_def(qpath, expr.hir_id);
if self.id == local_id;
then {
if_chain! {
if block.expr.is_none();
if let Some(expr) = block.stmts.iter().last();
- if let hir::StmtSemi(ref expr, _) = expr.node;
- if let hir::ExprAssign(ref var, ref value) = expr.node;
- if let hir::ExprPath(ref qpath) = var.node;
+ if let hir::StmtKind::Semi(ref expr, _) = expr.node;
+ if let hir::ExprKind::Assign(ref var, ref value) = expr.node;
+ if let hir::ExprKind::Path(ref qpath) = var.node;
if let Def::Local(local_id) = cx.tables.qpath_def(qpath, var.hir_id);
if decl == local_id;
then {
let mut v = UsedVisitor {
- cx: cx,
+ cx,
id: decl,
used: false,
};
-
+
for s in block.stmts.iter().take(block.stmts.len()-1) {
hir::intravisit::walk_stmt(&mut v, s);
-
+
if v.used {
return None;
}
}
-
+
return Some(value);
}
}
fn used_in_expr<'a, 'tcx: 'a>(cx: &LateContext<'a, 'tcx>, id: ast::NodeId, expr: &'tcx hir::Expr) -> bool {
let mut v = UsedVisitor {
- cx: cx,
- id: id,
+ cx,
+ id,
used: false,
};
hir::intravisit::walk_expr(&mut v, expr);