-use rustc::lint::*;
+use if_chain::if_chain;
+use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use rustc::{declare_lint_pass, declare_tool_lint};
+use crate::utils::sym;
+use crate::utils::{
+ higher::if_block, in_macro_or_desugar, match_type, paths, span_lint_and_then, usage::is_potentially_mutated,
+};
use rustc::hir::intravisit::*;
use rustc::hir::*;
-use syntax::ast::NodeId;
-use syntax::codemap::Span;
-use crate::utils::{in_macro, match_type, paths, usage::is_potentially_mutated};
+use syntax::source_map::Span;
-/// **What it does:** Checks for calls of unwrap[_err]() that cannot fail.
-///
-/// **Why is this bad?** Using `if let` or `match` is more idiomatic.
-///
-/// **Known problems:** Limitations of the borrow checker might make unwrap() necessary sometimes?
-///
-/// **Example:**
-/// ```rust
-/// if option.is_some() {
-/// do_something_with(option.unwrap())
-/// }
-/// ```
-///
-/// Could be written:
-///
-/// ```rust
-/// if let Some(value) = option {
-/// do_something_with(value)
-/// }
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for calls of `unwrap[_err]()` that cannot fail.
+ ///
+ /// **Why is this bad?** Using `if let` or `match` is more idiomatic.
+ ///
+ /// **Known problems:** Limitations of the borrow checker might make unwrap() necessary sometimes?
+ ///
+ /// **Example:**
+ /// ```rust
+ /// if option.is_some() {
+ /// do_something_with(option.unwrap())
+ /// }
+ /// ```
+ ///
+ /// Could be written:
+ ///
+ /// ```rust
+ /// if let Some(value) = option {
+ /// do_something_with(value)
+ /// }
+ /// ```
pub UNNECESSARY_UNWRAP,
- complexity,
+ nursery,
"checks for calls of unwrap[_err]() that cannot fail"
}
-pub struct Pass;
+declare_clippy_lint! {
+ /// **What it does:** Checks for calls of `unwrap[_err]()` that will always fail.
+ ///
+ /// **Why is this bad?** If panicking is desired, an explicit `panic!()` should be used.
+ ///
+ /// **Known problems:** This lint only checks `if` conditions not assignments.
+ /// So something like `let x: Option<()> = None; x.unwrap();` will not be recognized.
+ ///
+ /// **Example:**
+ /// ```rust
+ /// if option.is_none() {
+ /// do_something_with(option.unwrap())
+ /// }
+ /// ```
+ ///
+ /// This code will always panic. The if condition should probably be inverted.
+ pub PANICKING_UNWRAP,
+ nursery,
+ "checks for calls of unwrap[_err]() that will always fail"
+}
/// Visitor that keeps track of which variables are unwrappable.
struct UnwrappableVariablesVisitor<'a, 'tcx: 'a> {
expr: &'tcx Expr,
invert: bool,
) -> Vec<UnwrapInfo<'tcx>> {
- if let Expr_::ExprBinary(op, left, right) = &expr.node {
+ if let ExprKind::Binary(op, left, right) = &expr.node {
match (invert, op.node) {
- (false, BinOp_::BiAnd) | (false, BinOp_::BiBitAnd) | (true, BinOp_::BiOr) | (true, BinOp_::BiBitOr) => {
+ (false, BinOpKind::And) | (false, BinOpKind::BitAnd) | (true, BinOpKind::Or) | (true, BinOpKind::BitOr) => {
let mut unwrap_info = collect_unwrap_info(cx, left, invert);
unwrap_info.append(&mut collect_unwrap_info(cx, right, invert));
return unwrap_info;
},
_ => (),
}
- } else if let Expr_::ExprUnary(UnNot, expr) = &expr.node {
+ } else if let ExprKind::Unary(UnNot, expr) = &expr.node {
return collect_unwrap_info(cx, expr, !invert);
} else {
if_chain! {
- if let Expr_::ExprMethodCall(method_name, _, args) = &expr.node;
- if let Expr_::ExprPath(QPath::Resolved(None, path)) = &args[0].node;
+ if let ExprKind::MethodCall(method_name, _, args) = &expr.node;
+ if let ExprKind::Path(QPath::Resolved(None, path)) = &args[0].node;
let ty = cx.tables.expr_ty(&args[0]);
- if match_type(cx, ty, &paths::OPTION) || match_type(cx, ty, &paths::RESULT);
- let name = method_name.name.as_str();
+ if match_type(cx, ty, &*paths::OPTION) || match_type(cx, ty, &*paths::RESULT);
+ let name = method_name.ident.as_str();
if ["is_some", "is_none", "is_ok", "is_err"].contains(&&*name);
then {
assert!(args.len() == 1);
impl<'a, 'tcx: 'a> Visitor<'tcx> for UnwrappableVariablesVisitor<'a, 'tcx> {
fn visit_expr(&mut self, expr: &'tcx Expr) {
- if let Expr_::ExprIf(cond, then, els) = &expr.node {
+ if let Some((cond, then, els)) = if_block(&expr) {
walk_expr(self, cond);
self.visit_branch(cond, then, false);
if let Some(els) = els {
} else {
// find `unwrap[_err]()` calls:
if_chain! {
- if let Expr_::ExprMethodCall(ref method_name, _, ref args) = expr.node;
- if let Expr_::ExprPath(QPath::Resolved(None, ref path)) = args[0].node;
- if ["unwrap", "unwrap_err"].contains(&&*method_name.name.as_str());
- let call_to_unwrap = method_name.name == "unwrap";
+ if let ExprKind::MethodCall(ref method_name, _, ref args) = expr.node;
+ if let ExprKind::Path(QPath::Resolved(None, ref path)) = args[0].node;
+ if [*sym::unwrap, *sym::unwrap_err].contains(&method_name.ident.name);
+ let call_to_unwrap = method_name.ident.name == *sym::unwrap;
if let Some(unwrappable) = self.unwrappables.iter()
- .find(|u| u.ident.def == path.def && call_to_unwrap == u.safe_to_unwrap);
+ .find(|u| u.ident.res == path.res);
then {
- self.cx.span_lint_note(
- UNNECESSARY_UNWRAP,
- expr.span,
- &format!("You checked before that `{}()` cannot fail. \
- Instead of checking and unwrapping, it's better to use `if let` or `match`.",
- method_name.name),
- unwrappable.check.span,
- "the check is happening here",
- );
+ if call_to_unwrap == unwrappable.safe_to_unwrap {
+ span_lint_and_then(
+ self.cx,
+ UNNECESSARY_UNWRAP,
+ expr.span,
+ &format!("You checked before that `{}()` cannot fail. \
+ Instead of checking and unwrapping, it's better to use `if let` or `match`.",
+ method_name.ident.name),
+ |db| { db.span_label(unwrappable.check.span, "the check is happening here"); },
+ );
+ } else {
+ span_lint_and_then(
+ self.cx,
+ PANICKING_UNWRAP,
+ expr.span,
+ &format!("This call to `{}()` will always panic.",
+ method_name.ident.name),
+ |db| { db.span_label(unwrappable.check.span, "because of this check"); },
+ );
+ }
}
}
walk_expr(self, expr);
}
fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
- NestedVisitorMap::OnlyBodies(&self.cx.tcx.hir)
+ NestedVisitorMap::OnlyBodies(&self.cx.tcx.hir())
}
}
-impl<'a> LintPass for Pass {
- fn get_lints(&self) -> LintArray {
- lint_array!(UNNECESSARY_UNWRAP)
- }
-}
+declare_lint_pass!(Unwrap => [PANICKING_UNWRAP, UNNECESSARY_UNWRAP]);
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
+impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Unwrap {
fn check_fn(
&mut self,
cx: &LateContext<'a, 'tcx>,
decl: &'tcx FnDecl,
body: &'tcx Body,
span: Span,
- fn_id: NodeId,
+ fn_id: HirId,
) {
- if in_macro(span) {
+ if in_macro_or_desugar(span) {
return;
}
projects / rust.git / blobdiff