-use crate::utils::{higher, qpath_res, snippet, span_lint_and_then};
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::source::snippet;
+use clippy_utils::{path_to_local_id, visitors::LocalUsedVisitor};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
-use rustc_hir::def::Res;
-use rustc_hir::intravisit;
use rustc_hir::BindingAnnotation;
use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::hir::map::Map;
use rustc_session::{declare_lint_pass, declare_tool_lint};
declare_clippy_lint! {
- /// **What it does:** Checks for variable declarations immediately followed by a
+ /// ### What it does
+ /// Checks for variable declarations immediately followed by a
/// conditional affectation.
///
- /// **Why is this bad?** This is not idiomatic Rust.
+ /// ### Why is this bad?
+ /// This is not idiomatic Rust.
///
- /// **Known problems:** None.
- ///
- /// **Example:**
+ /// ### Example
/// ```rust,ignore
/// let foo;
///
declare_lint_pass!(LetIfSeq => [USELESS_LET_IF_SEQ]);
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for LetIfSeq {
- fn check_block(&mut self, cx: &LateContext<'a, 'tcx>, block: &'tcx hir::Block<'_>) {
+impl<'tcx> LateLintPass<'tcx> for LetIfSeq {
+ fn check_block(&mut self, cx: &LateContext<'tcx>, block: &'tcx hir::Block<'_>) {
let mut it = block.stmts.iter().peekable();
while let Some(stmt) = it.next() {
if_chain! {
if let Some(expr) = it.peek();
- if let hir::StmtKind::Local(ref local) = stmt.kind;
+ if let hir::StmtKind::Local(local) = stmt.kind;
if let hir::PatKind::Binding(mode, canonical_id, ident, None) = local.pat.kind;
- if let hir::StmtKind::Expr(ref if_) = expr.kind;
- if let Some((ref cond, ref then, ref else_)) = higher::if_block(&if_);
- if !used_in_expr(cx, canonical_id, cond);
- if let hir::ExprKind::Block(ref then, _) = then.kind;
+ if let hir::StmtKind::Expr(if_) = expr.kind;
+ if let hir::ExprKind::If(hir::Expr { kind: hir::ExprKind::DropTemps(cond), ..}, then, else_) = if_.kind;
+ let mut used_visitor = LocalUsedVisitor::new(cx, canonical_id);
+ if !used_visitor.check_expr(cond);
+ if let hir::ExprKind::Block(then, _) = then.kind;
if let Some(value) = check_assign(cx, canonical_id, &*then);
- if !used_in_expr(cx, canonical_id, value);
+ if !used_visitor.check_expr(value);
then {
let span = stmt.span.to(if_.span);
- let has_interior_mutability = !cx.tables.node_type(canonical_id).is_freeze(
+ let has_interior_mutability = !cx.typeck_results().node_type(canonical_id).is_freeze(
cx.tcx.at(span),
cx.param_env,
);
if has_interior_mutability { return; }
- let (default_multi_stmts, default) = if let Some(ref else_) = *else_ {
- if let hir::ExprKind::Block(ref else_, _) = else_.kind {
+ let (default_multi_stmts, default) = if let Some(else_) = else_ {
+ if let hir::ExprKind::Block(else_, _) = else_.kind {
if let Some(default) = check_assign(cx, canonical_id, else_) {
(else_.stmts.len() > 1, default)
- } else if let Some(ref default) = local.init {
- (true, &**default)
+ } else if let Some(default) = local.init {
+ (true, default)
} else {
continue;
}
} else {
continue;
}
- } else if let Some(ref default) = local.init {
- (false, &**default)
+ } else if let Some(default) = local.init {
+ (false, default)
} else {
continue;
};
}
}
-struct UsedVisitor<'a, 'tcx> {
- cx: &'a LateContext<'a, 'tcx>,
- id: hir::HirId,
- used: bool,
-}
-
-impl<'a, 'tcx> intravisit::Visitor<'tcx> for UsedVisitor<'a, 'tcx> {
- type Map = Map<'tcx>;
-
- fn visit_expr(&mut self, expr: &'tcx hir::Expr<'_>) {
- if_chain! {
- if let hir::ExprKind::Path(ref qpath) = expr.kind;
- if let Res::Local(local_id) = qpath_res(self.cx, qpath, expr.hir_id);
- if self.id == local_id;
- then {
- self.used = true;
- return;
- }
- }
- intravisit::walk_expr(self, expr);
- }
- fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> {
- intravisit::NestedVisitorMap::None
- }
-}
-
-fn check_assign<'a, 'tcx>(
- cx: &LateContext<'a, 'tcx>,
+fn check_assign<'tcx>(
+ cx: &LateContext<'tcx>,
decl: hir::HirId,
block: &'tcx hir::Block<'_>,
) -> Option<&'tcx hir::Expr<'tcx>> {
if_chain! {
if block.expr.is_none();
if let Some(expr) = block.stmts.iter().last();
- if let hir::StmtKind::Semi(ref expr) = expr.kind;
- if let hir::ExprKind::Assign(ref var, ref value, _) = expr.kind;
- if let hir::ExprKind::Path(ref qpath) = var.kind;
- if let Res::Local(local_id) = qpath_res(cx, qpath, var.hir_id);
- if decl == local_id;
+ if let hir::StmtKind::Semi(expr) = expr.kind;
+ if let hir::ExprKind::Assign(var, value, _) = expr.kind;
+ if path_to_local_id(var, decl);
then {
- let mut v = UsedVisitor {
- cx,
- id: decl,
- used: false,
- };
-
- for s in block.stmts.iter().take(block.stmts.len()-1) {
- intravisit::walk_stmt(&mut v, s);
+ let mut v = LocalUsedVisitor::new(cx, decl);
- if v.used {
- return None;
- }
+ if block.stmts.iter().take(block.stmts.len()-1).any(|stmt| v.check_stmt(stmt)) {
+ return None;
}
return Some(value);
None
}
-
-fn used_in_expr<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, id: hir::HirId, expr: &'tcx hir::Expr<'_>) -> bool {
- let mut v = UsedVisitor { cx, id, used: false };
- intravisit::walk_expr(&mut v, expr);
- v.used
-}
projects / rust.git / blobdiff