//! lint on manually implemented checked conversions that could be transformed into `try_from`
use if_chain::if_chain;
+use rustc::declare_lint_pass;
use rustc::hir::*;
use rustc::lint::{in_external_macro, LateContext, LateLintPass, LintArray, LintContext, LintPass};
-use rustc::{declare_lint_pass, declare_tool_lint};
+use rustc_errors::Applicability;
+use rustc_session::declare_tool_lint;
use syntax::ast::LitKind;
-use crate::utils::{span_lint, SpanlessEq};
+use crate::utils::{snippet_with_applicability, span_lint_and_sugg, SpanlessEq};
declare_clippy_lint! {
/// **What it does:** Checks for explicit bounds checking when casting.
/// Could be written:
///
/// ```rust
+ /// # use std::convert::TryFrom;
+ /// # let foo = 1;
/// # let _ =
/// i32::try_from(foo).is_ok()
/// # ;
fn check_expr(&mut self, cx: &LateContext<'_, '_>, item: &Expr) {
let result = if_chain! {
if !in_external_macro(cx.sess(), item.span);
- if let ExprKind::Binary(op, ref left, ref right) = &item.node;
+ if let ExprKind::Binary(op, ref left, ref right) = &item.kind;
then {
match op.node {
}
};
- if let Some(cv) = result {
- span_lint(
- cx,
- CHECKED_CONVERSIONS,
- item.span,
- &format!(
- "Checked cast can be simplified: `{}::try_from`",
- cv.to_type.unwrap_or_else(|| "IntegerType".to_string()),
- ),
- );
+ if_chain! {
+ if let Some(cv) = result;
+ if let Some(to_type) = cv.to_type;
+
+ then {
+ let mut applicability = Applicability::MachineApplicable;
+ let snippet = snippet_with_applicability(cx, cv.expr_to_cast.span, "_", &mut
+ applicability);
+ span_lint_and_sugg(
+ cx,
+ CHECKED_CONVERSIONS,
+ item.span,
+ "Checked cast can be simplified.",
+ "try",
+ format!("{}::try_from({}).is_ok()",
+ to_type,
+ snippet),
+ applicability
+ );
+ }
}
}
}
struct Conversion<'a> {
cvt: ConversionType,
expr_to_cast: &'a Expr,
- to_type: Option<String>,
+ to_type: Option<&'a str>,
}
/// The kind of conversion that is checked
/// Checks if the to-type is the same (if there is a type constraint)
fn has_compatible_to_type(&self, other: &Self) -> bool {
- transpose(self.to_type.as_ref(), other.to_type.as_ref())
- .map(|(l, r)| l == r)
- .unwrap_or(true)
+ transpose(self.to_type.as_ref(), other.to_type.as_ref()).map_or(true, |(l, r)| l == r)
}
/// Try to construct a new conversion if the conversion type is valid
- fn try_new<'b>(expr_to_cast: &'a Expr, from_type: &'b str, to_type: String) -> Option<Conversion<'a>> {
- ConversionType::try_new(from_type, &to_type).map(|cvt| Conversion {
+ fn try_new(expr_to_cast: &'a Expr, from_type: &str, to_type: &'a str) -> Option<Conversion<'a>> {
+ ConversionType::try_new(from_type, to_type).map(|cvt| Conversion {
cvt,
expr_to_cast,
to_type: Some(to_type),
impl ConversionType {
/// Creates a conversion type if the type is allowed & conversion is valid
- fn try_new(from: &str, to: &str) -> Option<ConversionType> {
- if UNSIGNED_TYPES.contains(&from) {
- Some(ConversionType::FromUnsigned)
- } else if SIGNED_TYPES.contains(&from) {
- if UNSIGNED_TYPES.contains(&to) {
- Some(ConversionType::SignedToUnsigned)
- } else if SIGNED_TYPES.contains(&to) {
- Some(ConversionType::SignedToSigned)
+ #[must_use]
+ fn try_new(from: &str, to: &str) -> Option<Self> {
+ if UINTS.contains(&from) {
+ Some(Self::FromUnsigned)
+ } else if SINTS.contains(&from) {
+ if UINTS.contains(&to) {
+ Some(Self::SignedToUnsigned)
+ } else if SINTS.contains(&to) {
+ Some(Self::SignedToSigned)
} else {
None
}
/// Check for `expr <= (to_type::max_value() as from_type)`
fn check_upper_bound(expr: &Expr) -> Option<Conversion<'_>> {
if_chain! {
- if let ExprKind::Binary(ref op, ref left, ref right) = &expr.node;
+ if let ExprKind::Binary(ref op, ref left, ref right) = &expr.kind;
if let Some((candidate, check)) = normalize_le_ge(op, left, right);
- if let Some((from, to)) = get_types_from_cast(check, "max_value", INT_TYPES);
+ if let Some((from, to)) = get_types_from_cast(check, MAX_VALUE, INTS);
then {
- Conversion::try_new(candidate, &from, to)
+ Conversion::try_new(candidate, from, to)
} else {
None
}
}
// First of we need a binary containing the expression & the cast
- if let ExprKind::Binary(ref op, ref left, ref right) = &expr.node {
+ if let ExprKind::Binary(ref op, ref left, ref right) = &expr.kind {
normalize_le_ge(op, right, left).and_then(|(l, r)| check_function(l, r))
} else {
None
/// Check for `expr >= 0`
fn check_lower_bound_zero<'a>(candidate: &'a Expr, check: &'a Expr) -> Option<Conversion<'a>> {
if_chain! {
- if let ExprKind::Lit(ref lit) = &check.node;
+ if let ExprKind::Lit(ref lit) = &check.kind;
if let LitKind::Int(0, _) = &lit.node;
then {
/// Check for `expr >= (to_type::min_value() as from_type)`
fn check_lower_bound_min<'a>(candidate: &'a Expr, check: &'a Expr) -> Option<Conversion<'a>> {
- if let Some((from, to)) = get_types_from_cast(check, "min_value", SIGNED_TYPES) {
- Conversion::try_new(candidate, &from, to)
+ if let Some((from, to)) = get_types_from_cast(check, MIN_VALUE, SINTS) {
+ Conversion::try_new(candidate, from, to)
} else {
None
}
}
/// Tries to extract the from- and to-type from a cast expression
-fn get_types_from_cast(expr: &Expr, func: &str, types: &[&str]) -> Option<(String, String)> {
+fn get_types_from_cast<'a>(expr: &'a Expr, func: &'a str, types: &'a [&str]) -> Option<(&'a str, &'a str)> {
// `to_type::maxmin_value() as from_type`
- let call_from_cast: Option<(&Expr, String)> = if_chain! {
+ let call_from_cast: Option<(&Expr, &str)> = if_chain! {
// to_type::maxmin_value(), from_type
- if let ExprKind::Cast(ref limit, ref from_type) = &expr.node;
- if let TyKind::Path(ref from_type_path) = &from_type.node;
- if let Some(from_type_str) = int_ty_to_str(from_type_path);
+ if let ExprKind::Cast(ref limit, ref from_type) = &expr.kind;
+ if let TyKind::Path(ref from_type_path) = &from_type.kind;
+ if let Some(from_sym) = int_ty_to_sym(from_type_path);
then {
- Some((limit, from_type_str.to_string()))
+ Some((limit, from_sym))
} else {
None
}
};
// `from_type::from(to_type::maxmin_value())`
- let limit_from: Option<(&Expr, String)> = call_from_cast.or_else(|| {
+ let limit_from: Option<(&Expr, &str)> = call_from_cast.or_else(|| {
if_chain! {
// `from_type::from, to_type::maxmin_value()`
- if let ExprKind::Call(ref from_func, ref args) = &expr.node;
+ if let ExprKind::Call(ref from_func, ref args) = &expr.kind;
// `to_type::maxmin_value()`
if args.len() == 1;
if let limit = &args[0];
// `from_type::from`
- if let ExprKind::Path(ref path) = &from_func.node;
- if let Some(from_type) = get_implementing_type(path, INT_TYPES, "from");
+ if let ExprKind::Path(ref path) = &from_func.kind;
+ if let Some(from_sym) = get_implementing_type(path, INTS, FROM);
then {
- Some((limit, from_type))
+ Some((limit, from_sym))
} else {
None
}
if let Some((limit, from_type)) = limit_from {
if_chain! {
- if let ExprKind::Call(ref fun_name, _) = &limit.node;
+ if let ExprKind::Call(ref fun_name, _) = &limit.kind;
// `to_type, maxmin_value`
- if let ExprKind::Path(ref path) = &fun_name.node;
+ if let ExprKind::Path(ref path) = &fun_name.kind;
// `to_type`
if let Some(to_type) = get_implementing_type(path, types, func);
}
/// Gets the type which implements the called function
-fn get_implementing_type(path: &QPath, candidates: &[&str], function: &str) -> Option<String> {
+fn get_implementing_type<'a>(path: &QPath, candidates: &'a [&str], function: &str) -> Option<&'a str> {
if_chain! {
if let QPath::TypeRelative(ref ty, ref path) = &path;
- if path.ident.name == function;
- if let TyKind::Path(QPath::Resolved(None, ref tp)) = &ty.node;
+ if path.ident.name.as_str() == function;
+ if let TyKind::Path(QPath::Resolved(None, ref tp)) = &ty.kind;
if let [int] = &*tp.segments;
- let name = int.ident.as_str().get();
- if candidates.contains(&name);
+ let name = &int.ident.name.as_str();
then {
- Some(name.to_string())
+ candidates.iter().find(|c| name == *c).cloned()
} else {
None
}
}
/// Gets the type as a string, if it is a supported integer
-fn int_ty_to_str(path: &QPath) -> Option<&str> {
+fn int_ty_to_sym(path: &QPath) -> Option<&str> {
if_chain! {
if let QPath::Resolved(_, ref path) = *path;
if let [ty] = &*path.segments;
+ let name = &ty.ident.name.as_str();
then {
- INT_TYPES
- .iter()
- .find(|c| (&ty.ident.name) == *c)
- .cloned()
+ INTS.iter().find(|c| name == *c).cloned()
} else {
None
}
}
/// Will return the expressions as if they were expr1 <= expr2
-fn normalize_le_ge<'a>(op: &'a BinOp, left: &'a Expr, right: &'a Expr) -> Option<(&'a Expr, &'a Expr)> {
+fn normalize_le_ge<'a>(op: &BinOp, left: &'a Expr, right: &'a Expr) -> Option<(&'a Expr, &'a Expr)> {
match op.node {
BinOpKind::Le => Some((left, right)),
BinOpKind::Ge => Some((right, left)),
}
}
-const UNSIGNED_TYPES: &[&str] = &["u8", "u16", "u32", "u64", "u128", "usize"];
-const SIGNED_TYPES: &[&str] = &["i8", "i16", "i32", "i64", "i128", "isize"];
-const INT_TYPES: &[&str] = &[
- "u8", "u16", "u32", "u64", "u128", "usize", "i8", "i16", "i32", "i64", "i128", "isize",
-];
+// Constants
+const FROM: &str = "from";
+const MAX_VALUE: &str = "max_value";
+const MIN_VALUE: &str = "min_value";
+
+const UINTS: &[&str] = &["u8", "u16", "u32", "u64", "usize"];
+const SINTS: &[&str] = &["i8", "i16", "i32", "i64", "isize"];
+const INTS: &[&str] = &["u8", "u16", "u32", "u64", "usize", "i8", "i16", "i32", "i64", "isize"];
projects / rust.git / blobdiff