-use crate::utils::{path_to_local_id, snippet, span_lint_and_then, visitors::LocalUsedVisitor};
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::source::snippet;
+use clippy_utils::{path_to_local_id, visitors::is_local_used};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
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;
///
/// None
/// };
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub USELESS_LET_IF_SEQ,
nursery,
"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::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 hir::ExprKind::If(ref cond, ref then, ref else_) = if_.kind;
- if !LocalUsedVisitor::new(canonical_id).check_expr(cond);
- if let hir::ExprKind::Block(ref then, _) = then.kind;
- if let Some(value) = check_assign(canonical_id, &*then);
- if !LocalUsedVisitor::new(canonical_id).check_expr(value);
+ if let hir::StmtKind::Expr(if_) = expr.kind;
+ if let hir::ExprKind::If(hir::Expr { kind: hir::ExprKind::DropTemps(cond), ..}, then, else_) = if_.kind;
+ if !is_local_used(cx, *cond, canonical_id);
+ if let hir::ExprKind::Block(then, _) = then.kind;
+ if let Some(value) = check_assign(cx, canonical_id, then);
+ if !is_local_used(cx, value, canonical_id);
then {
let span = stmt.span.to(if_.span);
);
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 {
- if let Some(default) = check_assign(canonical_id, else_) {
+ 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;
};
}
}
-fn check_assign<'tcx>(decl: hir::HirId, block: &'tcx hir::Block<'_>) -> Option<&'tcx hir::Expr<'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::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 = LocalUsedVisitor::new(decl);
-
- if block.stmts.iter().take(block.stmts.len()-1).any(|stmt| v.check_stmt(stmt)) {
- return None;
+ if block.stmts.iter().take(block.stmts.len()-1).any(|stmt| is_local_used(cx, stmt, decl)) {
+ None
+ } else {
+ Some(value)
}
-
- return Some(value);
+ } else {
+ None
}
}
-
- None
}