use syntax::ast_util::{is_comparison_binop, binop_to_string};
use syntax::visit::{FnKind};
use rustc::lint::{Context, LintPass, LintArray, Lint, Level};
-use rustc::middle::ty::{self, expr_ty, ty_str, ty_ptr, ty_rptr, ty_float};
+use rustc::middle::ty;
use syntax::codemap::{Span, Spanned};
+use utils::{match_path, snippet, span_lint, span_help_and_lint};
-use types::span_note_and_lint;
-
-fn walk_ty<'t>(ty: ty::Ty<'t>) -> ty::Ty<'t> {
- match ty.sty {
- ty_ptr(ref tm) | ty_rptr(_, ref tm) => walk_ty(tm.ty),
- _ => ty
- }
+pub fn walk_ty<'t>(ty: ty::Ty<'t>) -> ty::Ty<'t> {
+ match ty.sty {
+ ty::TyRef(_, ref tm) | ty::TyRawPtr(ref tm) => walk_ty(tm.ty),
+ _ => ty
+ }
}
/// Handles uncategorized lints
if arms.len() == 2 {
if arms[0].guard.is_none() && arms[1].pats.len() == 1 {
match arms[1].body.node {
- ExprTup(ref v) if v.len() == 0 && arms[1].guard.is_none() => (),
- ExprBlock(ref b) if b.stmts.len() == 0 && arms[1].guard.is_none() => (),
+ ExprTup(ref v) if v.is_empty() && arms[1].guard.is_none() => (),
+ ExprBlock(ref b) if b.stmts.is_empty() && arms[1].guard.is_none() => (),
_ => return
}
// In some cases, an exhaustive match is preferred to catch situations when
// an enum is extended. So we only consider cases where a `_` wildcard is used
- if arms[1].pats[0].node == PatWild(PatWildSingle) && arms[0].pats.len() == 1 {
- let map = cx.sess().codemap();
- span_note_and_lint(cx, SINGLE_MATCH, expr.span,
- "You seem to be trying to use match for destructuring a single type. Did you mean to use `if let`?",
+ if arms[1].pats[0].node == PatWild(PatWildSingle) &&
+ arms[0].pats.len() == 1 {
+ span_help_and_lint(cx, SINGLE_MATCH, expr.span,
+ "You seem to be trying to use match for \
+ destructuring a single type. Did you mean to \
+ use `if let`?",
&*format!("Try if let {} = {} {{ ... }}",
- &*map.span_to_snippet(arms[0].pats[0].span).unwrap_or("..".to_string()),
- &*map.span_to_snippet(ex.span).unwrap_or("..".to_string()))
+ snippet(cx, arms[0].pats[0].span, ".."),
+ snippet(cx, ex.span, ".."))
);
}
}
fn check_expr(&mut self, cx: &Context, expr: &ast::Expr) {
match expr.node {
ast::ExprMethodCall(ref method, _, ref args)
- if method.node.as_str() == "to_string"
+ if method.node.name == "to_string"
&& is_str(cx, &*args[0]) => {
- cx.span_lint(STR_TO_STRING, expr.span, "str.to_owned() is faster");
+ span_lint(cx, STR_TO_STRING, expr.span, "str.to_owned() is faster");
},
_ => ()
}
fn is_str(cx: &Context, expr: &ast::Expr) -> bool {
- match walk_ty(expr_ty(cx.tcx, expr)).sty {
- ty_str => true,
+ match walk_ty(cx.tcx.expr_ty(expr)).sty {
+ ty::TyStr => true,
_ => false
}
}
fn check_fn(&mut self, cx: &Context, _: FnKind, decl: &FnDecl, _: &Block, _: Span, _: NodeId) {
for ref arg in decl.inputs.iter() {
if let PatIdent(BindByRef(_), _, _) = arg.pat.node {
- cx.span_lint(
+ span_lint(cx,
TOPLEVEL_REF_ARG,
arg.pat.span,
"`ref` directly on a function argument is ignored. Have you considered using a reference type instead?"
pub struct CmpNan;
impl LintPass for CmpNan {
- fn get_lints(&self) -> LintArray {
+ fn get_lints(&self) -> LintArray {
lint_array!(CMP_NAN)
- }
-
- fn check_expr(&mut self, cx: &Context, expr: &Expr) {
- if let ExprBinary(ref cmp, ref left, ref right) = expr.node {
- if is_comparison_binop(cmp.node) {
- if let &ExprPath(_, ref path) = &left.node {
- check_nan(cx, path, expr.span);
- }
- if let &ExprPath(_, ref path) = &right.node {
- check_nan(cx, path, expr.span);
- }
- }
- }
- }
+ }
+
+ fn check_expr(&mut self, cx: &Context, expr: &Expr) {
+ if let ExprBinary(ref cmp, ref left, ref right) = expr.node {
+ if is_comparison_binop(cmp.node) {
+ if let &ExprPath(_, ref path) = &left.node {
+ check_nan(cx, path, expr.span);
+ }
+ if let &ExprPath(_, ref path) = &right.node {
+ check_nan(cx, path, expr.span);
+ }
+ }
+ }
+ }
}
fn check_nan(cx: &Context, path: &Path, span: Span) {
- path.segments.last().map(|seg| if seg.identifier.as_str() == "NAN" {
- cx.span_lint(CMP_NAN, span, "Doomed comparison with NAN, use std::{f32,f64}::is_nan instead");
- });
+ path.segments.last().map(|seg| if seg.identifier.name == "NAN" {
+ span_lint(cx, CMP_NAN, span,
+ "Doomed comparison with NAN, use std::{f32,f64}::is_nan instead");
+ });
}
declare_lint!(pub FLOAT_CMP, Warn,
- "Warn on ==/!= comparison of floaty values");
-
+ "Warn on ==/!= comparison of floaty values");
+
#[derive(Copy,Clone)]
pub struct FloatCmp;
impl LintPass for FloatCmp {
- fn get_lints(&self) -> LintArray {
+ fn get_lints(&self) -> LintArray {
lint_array!(FLOAT_CMP)
- }
-
- fn check_expr(&mut self, cx: &Context, expr: &Expr) {
- if let ExprBinary(ref cmp, ref left, ref right) = expr.node {
- let op = cmp.node;
- if (op == BiEq || op == BiNe) && (is_float(cx, left) || is_float(cx, right)) {
- let map = cx.sess().codemap();
- cx.span_lint(FLOAT_CMP, expr.span, &format!(
- "{}-Comparison of f32 or f64 detected. You may want to change this to 'abs({} - {}) < epsilon' for some suitable value of epsilon",
- binop_to_string(op), &*map.span_to_snippet(left.span).unwrap_or("..".to_string()),
- &*map.span_to_snippet(right.span).unwrap_or("..".to_string())));
- }
- }
- }
+ }
+
+ fn check_expr(&mut self, cx: &Context, expr: &Expr) {
+ if let ExprBinary(ref cmp, ref left, ref right) = expr.node {
+ let op = cmp.node;
+ if (op == BiEq || op == BiNe) && (is_float(cx, left) || is_float(cx, right)) {
+ span_lint(cx, FLOAT_CMP, expr.span, &format!(
+ "{}-Comparison of f32 or f64 detected. You may want to change this to 'abs({} - {}) < epsilon' for some suitable value of epsilon",
+ binop_to_string(op), snippet(cx, left.span, ".."),
+ snippet(cx, right.span, "..")));
+ }
+ }
+ }
}
fn is_float(cx: &Context, expr: &Expr) -> bool {
- if let ty_float(_) = walk_ty(expr_ty(cx.tcx, expr)).sty { true } else { false }
+ if let ty::TyFloat(_) = walk_ty(cx.tcx.expr_ty(expr)).sty {
+ true
+ } else {
+ false
+ }
}
declare_lint!(pub PRECEDENCE, Warn,
- "Warn on mixing bit ops with integer arithmetic without parenthesis");
-
+ "Warn on mixing bit ops with integer arithmetic without parenthesis");
+
#[derive(Copy,Clone)]
pub struct Precedence;
impl LintPass for Precedence {
- fn get_lints(&self) -> LintArray {
+ fn get_lints(&self) -> LintArray {
lint_array!(PRECEDENCE)
- }
-
- fn check_expr(&mut self, cx: &Context, expr: &Expr) {
- if let ExprBinary(Spanned { node: op, ..}, ref left, ref right) = expr.node {
- if is_bit_op(op) && (is_arith_expr(left) || is_arith_expr(right)) {
- cx.span_lint(PRECEDENCE, expr.span,
- "Operator precedence can trip the unwary. Consider adding parenthesis to the subexpression.");
- }
- }
- }
+ }
+
+ fn check_expr(&mut self, cx: &Context, expr: &Expr) {
+ if let ExprBinary(Spanned { node: op, ..}, ref left, ref right) = expr.node {
+ if is_bit_op(op) && (is_arith_expr(left) || is_arith_expr(right)) {
+ span_lint(cx, PRECEDENCE, expr.span,
+ "Operator precedence can trip the unwary. Consider adding parenthesis to the subexpression.");
+ }
+ }
+ }
}
fn is_arith_expr(expr : &Expr) -> bool {
- match expr.node {
- ExprBinary(Spanned { node: op, ..}, _, _) => is_arith_op(op),
- _ => false
- }
+ match expr.node {
+ ExprBinary(Spanned { node: op, ..}, _, _) => is_arith_op(op),
+ _ => false
+ }
}
fn is_bit_op(op : BinOp_) -> bool {
- match op {
- BiBitXor | BiBitAnd | BiBitOr | BiShl | BiShr => true,
- _ => false
- }
+ match op {
+ BiBitXor | BiBitAnd | BiBitOr | BiShl | BiShr => true,
+ _ => false
+ }
}
fn is_arith_op(op : BinOp_) -> bool {
- match op {
- BiAdd | BiSub | BiMul | BiDiv | BiRem => true,
- _ => false
- }
+ match op {
+ BiAdd | BiSub | BiMul | BiDiv | BiRem => true,
+ _ => false
+ }
}
declare_lint!(pub CMP_OWNED, Warn,
- "Warn on creating an owned string just for comparison");
-
+ "Warn on creating an owned string just for comparison");
+
#[derive(Copy,Clone)]
pub struct CmpOwned;
impl LintPass for CmpOwned {
- fn get_lints(&self) -> LintArray {
+ fn get_lints(&self) -> LintArray {
lint_array!(CMP_OWNED)
- }
-
- fn check_expr(&mut self, cx: &Context, expr: &Expr) {
- if let ExprBinary(ref cmp, ref left, ref right) = expr.node {
- if is_comparison_binop(cmp.node) {
- check_to_owned(cx, left, right.span);
- check_to_owned(cx, right, left.span)
- }
- }
- }
+ }
+
+ fn check_expr(&mut self, cx: &Context, expr: &Expr) {
+ if let ExprBinary(ref cmp, ref left, ref right) = expr.node {
+ if is_comparison_binop(cmp.node) {
+ check_to_owned(cx, left, right.span);
+ check_to_owned(cx, right, left.span)
+ }
+ }
+ }
}
fn check_to_owned(cx: &Context, expr: &Expr, other_span: Span) {
- match &expr.node {
- &ExprMethodCall(Spanned{node: ref ident, ..}, _, ref args) => {
- let name = ident.as_str();
- if name == "to_string" ||
- name == "to_owned" && is_str_arg(cx, args) {
- cx.span_lint(CMP_OWNED, expr.span, &format!(
- "this creates an owned instance just for comparison. \
- Consider using {}.as_slice() to compare without allocation",
- cx.sess().codemap().span_to_snippet(other_span).unwrap_or(
- "..".to_string())))
- }
- },
- &ExprCall(ref path, _) => {
- if let &ExprPath(None, ref path) = &path.node {
- if path.segments.iter().zip(["String", "from_str"].iter()).all(
- |(seg, name)| &seg.identifier.as_str() == name) {
- cx.span_lint(CMP_OWNED, expr.span, &format!(
- "this creates an owned instance just for comparison. \
- Consider using {}.as_slice() to compare without allocation",
- cx.sess().codemap().span_to_snippet(other_span).unwrap_or(
- "..".to_string())))
- }
- }
- },
- _ => ()
- }
+ match &expr.node {
+ &ExprMethodCall(Spanned{node: ref ident, ..}, _, ref args) => {
+ let name = ident.name;
+ if name == "to_string" ||
+ name == "to_owned" && is_str_arg(cx, args) {
+ span_lint(cx, CMP_OWNED, expr.span, &format!(
+ "this creates an owned instance just for comparison. \
+ Consider using {}.as_slice() to compare without allocation",
+ snippet(cx, other_span, "..")))
+ }
+ },
+ &ExprCall(ref path, _) => {
+ if let &ExprPath(None, ref path) = &path.node {
+ if match_path(path, &["String", "from_str"]) ||
+ match_path(path, &["String", "from"]) {
+ span_lint(cx, CMP_OWNED, expr.span, &format!(
+ "this creates an owned instance just for comparison. \
+ Consider using {}.as_slice() to compare without allocation",
+ snippet(cx, other_span, "..")))
+ }
+ }
+ },
+ _ => ()
+ }
}
fn is_str_arg(cx: &Context, args: &[P<Expr>]) -> bool {
- args.len() == 1 && if let ty_str =
- walk_ty(expr_ty(cx.tcx, &*args[0])).sty { true } else { false }
+ args.len() == 1 && if let ty::TyStr =
+ walk_ty(cx.tcx.expr_ty(&*args[0])).sty { true } else { false }
+}
+
+declare_lint!(pub NEEDLESS_RETURN, Warn,
+ "Warn on using a return statement where an expression would be enough");
+
+#[derive(Copy,Clone)]
+pub struct NeedlessReturn;
+
+impl NeedlessReturn {
+ // Check the final stmt or expr in a block for unnecessary return.
+ fn check_block_return(&mut self, cx: &Context, block: &Block) {
+ if let Some(ref expr) = block.expr {
+ self.check_final_expr(cx, expr);
+ } else if let Some(stmt) = block.stmts.last() {
+ if let StmtSemi(ref expr, _) = stmt.node {
+ if let ExprRet(Some(ref inner)) = expr.node {
+ self.emit_lint(cx, (expr.span, inner.span));
+ }
+ }
+ }
+ }
+
+ // Check a the final expression in a block if it's a return.
+ fn check_final_expr(&mut self, cx: &Context, expr: &Expr) {
+ match expr.node {
+ // simple return is always "bad"
+ ExprRet(Some(ref inner)) => {
+ self.emit_lint(cx, (expr.span, inner.span));
+ }
+ // a whole block? check it!
+ ExprBlock(ref block) => {
+ self.check_block_return(cx, block);
+ }
+ // an if/if let expr, check both exprs
+ // note, if without else is going to be a type checking error anyways
+ // (except for unit type functions) so we don't match it
+ ExprIf(_, ref ifblock, Some(ref elsexpr)) |
+ ExprIfLet(_, _, ref ifblock, Some(ref elsexpr)) => {
+ self.check_block_return(cx, ifblock);
+ self.check_final_expr(cx, elsexpr);
+ }
+ // a match expr, check all arms
+ ExprMatch(_, ref arms, _) => {
+ for arm in arms {
+ self.check_final_expr(cx, &*arm.body);
+ }
+ }
+ _ => { }
+ }
+ }
+
+ fn emit_lint(&mut self, cx: &Context, spans: (Span, Span)) {
+ span_lint(cx, NEEDLESS_RETURN, spans.0, &format!(
+ "unneeded return statement. Consider using {} \
+ without the trailing semicolon",
+ snippet(cx, spans.1, "..")))
+ }
+}
+
+impl LintPass for NeedlessReturn {
+ fn get_lints(&self) -> LintArray {
+ lint_array!(NEEDLESS_RETURN)
+ }
+
+ fn check_fn(&mut self, cx: &Context, _: FnKind, _: &FnDecl,
+ block: &Block, _: Span, _: ast::NodeId) {
+ self.check_block_return(cx, block);
+ }
}
projects / rust.git / blobdiff