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Changed impl to use symbols.
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@pJunger
pJunger committed May 14, 2019
1 parent 00d6821 commit 928d5cc
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Showing 2 changed files with 47 additions and 31 deletions.
76 changes: 45 additions & 31 deletions clippy_lints/src/checked_conversions.rs
View file
Original file line number Diff line number Diff line change
@@ -1,12 +1,15 @@
//! lint on manually implemented checked conversions that could be transformed into `try_from`

use if_chain::if_chain;
use lazy_static::lazy_static;
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 syntax::ast::LitKind;
use crate::utils::{span_lint_and_sugg, snippet_with_applicability, SpanlessEq};
use syntax::symbol::Symbol;

use crate::utils::{snippet_with_applicability, span_lint_and_sugg, sym, SpanlessEq};

declare_clippy_lint! {
/// **What it does:** Checks for explicit bounds checking when casting.
Expand Down Expand Up @@ -101,7 +104,7 @@ fn double_check<'a>(cx: &LateContext<'_, '_>, left: &'a Expr, right: &'a Expr) -
struct Conversion<'a> {
cvt: ConversionType,
expr_to_cast: &'a Expr,
to_type: Option<String>,
to_type: Option<Symbol>,
}

/// The kind of conversion that is checked
Expand Down Expand Up @@ -137,8 +140,8 @@ impl<'a> Conversion<'a> {
}

/// 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<'b>(expr_to_cast: &'a Expr, from_type: Symbol, to_type: Symbol) -> Option<Conversion<'a>> {
ConversionType::try_new(from_type, to_type).map(|cvt| Conversion {
cvt,
expr_to_cast,
to_type: Some(to_type),
Expand All @@ -157,13 +160,13 @@ impl<'a> Conversion<'a> {

impl ConversionType {
/// Creates a conversion type if the type is allowed & conversion is valid
fn try_new(from: &str, to: &str) -> Option<Self> {
if UNSIGNED_TYPES.contains(&from) {
fn try_new(from: Symbol, to: Symbol) -> Option<Self> {
if UINTS.contains(&from) {
Some(ConversionType::FromUnsigned)
} else if SIGNED_TYPES.contains(&from) {
if UNSIGNED_TYPES.contains(&to) {
} else if SINTS.contains(&from) {
if UINTS.contains(&to) {
Some(ConversionType::SignedToUnsigned)
} else if SIGNED_TYPES.contains(&to) {
} else if SINTS.contains(&to) {
Some(ConversionType::SignedToSigned)
} else {
None
Expand All @@ -179,10 +182,10 @@ fn check_upper_bound(expr: &Expr) -> Option<Conversion<'_>> {
if_chain! {
if let ExprKind::Binary(ref op, ref left, ref right) = &expr.node;
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, *sym::max_value, &*INTS);

then {
Conversion::try_new(candidate, &from, to)
Conversion::try_new(candidate, from, to)
} else {
None
}
Expand Down Expand Up @@ -219,31 +222,31 @@ fn check_lower_bound_zero<'a>(candidate: &'a Expr, check: &'a Expr) -> Option<Co

/// 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, *sym::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(expr: &Expr, func: Symbol, types: &[Symbol]) -> Option<(Symbol, Symbol)> {
// `to_type::maxmin_value() as from_type`
let call_from_cast: Option<(&Expr, String)> = if_chain! {
let call_from_cast: Option<(&Expr, Symbol)> = 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 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, Symbol)> = 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;
Expand All @@ -252,10 +255,10 @@ fn get_types_from_cast(expr: &Expr, func: &str, types: &[&str]) -> Option<(Strin
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 Some(from_sym) = get_implementing_type(path, &*INTS, *sym::from);

then {
Some((limit, from_type))
Some((limit, from_sym))
} else {
None
}
Expand All @@ -282,33 +285,33 @@ fn get_types_from_cast(expr: &Expr, func: &str, types: &[&str]) -> Option<(Strin
}

/// Gets the type which implements the called function
fn get_implementing_type(path: &QPath, candidates: &[&str], function: &str) -> Option<String> {
fn get_implementing_type(path: &QPath, candidates: &[Symbol], function: Symbol) -> Option<Symbol> {
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 let [int] = &*tp.segments;
let name = int.ident.as_str().get();
let name = int.ident.name;
if candidates.contains(&name);

then {
Some(name.to_string())
Some(name)
} 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<Symbol> {
if_chain! {
if let QPath::Resolved(_, ref path) = *path;
if let [ty] = &*path.segments;

then {
INT_TYPES
INTS
.iter()
.find(|c| (&ty.ident.name) == *c)
.find(|c| ty.ident.name == **c)
.cloned()
} else {
None
Expand All @@ -333,8 +336,19 @@ fn normalize_le_ge<'a>(op: &'a BinOp, left: &'a Expr, right: &'a Expr) -> Option
}
}

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",
];
lazy_static! {
static ref UINTS: [Symbol; 5] = [*sym::u8, *sym::u16, *sym::u32, *sym::u64, *sym::usize];
static ref SINTS: [Symbol; 5] = [*sym::i8, *sym::i16, *sym::i32, *sym::i64, *sym::isize];
static ref INTS: [Symbol; 10] = [
*sym::u8,
*sym::u16,
*sym::u32,
*sym::u64,
*sym::usize,
*sym::i8,
*sym::i16,
*sym::i32,
*sym::i64,
*sym::isize
];
}
2 changes: 2 additions & 0 deletions clippy_lints/src/utils/sym.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -218,11 +218,13 @@ symbols_simple! {
MAX,
max_by,
max_by_key,
max_value,
mem,
min,
MIN,
min_by,
min_by_key,
min_value,
mpsc,
mul,
Mul,
Expand Down

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