bjoernager/rust
bjoernager/rust
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Reworked the error messages for more heplfulness.

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Renamed the cast_possible_overflow lint to cast_possible_truncation,
and updated the error message, readme and crate root accordingly.
Added some more information to the message for the cast_precision_loss
lint.
Updated the test case to reflect changes.
This commit is contained in:
R.Chavignat 2015-08-20 22:44:40 +02:00
parent ab481e5cb1
commit dbc9b7f46e
4 changed files with 70 additions and 69 deletions
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2
src/lib.rs
View file

@ -106,7 +106,7 @@ pub fn plugin_registrar(reg: &mut Registry) {
strings::STRING_ADD,
strings::STRING_ADD_ASSIGN,
types::BOX_VEC,
types::CAST_POSSIBLE_OVERFLOW,
types::CAST_POSSIBLE_TRUNCATION,
types::CAST_PRECISION_LOSS,
types::CAST_SIGN_LOSS,
types::LET_UNIT_VALUE,

23
src/types.rs
View file

@ -143,14 +143,14 @@ declare_lint!(pub CAST_PRECISION_LOSS, Allow,
"casts that cause loss of precision, e.g `x as f32` where `x: u64`");
declare_lint!(pub CAST_SIGN_LOSS, Allow,
"casts from signed types to unsigned types, e.g `x as u32` where `x: i32`");
declare_lint!(pub CAST_POSSIBLE_OVERFLOW, Allow,
"casts that may cause overflow, e.g `x as u8` where `x: u32`, or `x as i32` where `x: f32`");
declare_lint!(pub CAST_POSSIBLE_TRUNCATION, Allow,
"casts that may cause truncation of the value, e.g `x as u8` where `x: u32`, or `x as i32` where `x: f32`");
impl LintPass for CastPass {
fn get_lints(&self) -> LintArray {
lint_array!(CAST_PRECISION_LOSS,
CAST_SIGN_LOSS,
CAST_POSSIBLE_OVERFLOW)
CAST_POSSIBLE_TRUNCATION)
}
fn check_expr(&mut self, cx: &Context, expr: &Expr) {
@ -170,17 +170,18 @@ impl LintPass for CastPass {
_ => 0
};
if from_nbits != 4 {
// Handle TyIs/TyUs separately (size is arch dependant)
// Handle TyIs/TyUs separately (pointer size is arch dependant)
if from_nbits >= to_nbits {
span_lint(cx, CAST_PRECISION_LOSS, expr.span,
&format!("converting from {} to {}, which causes a loss of precision",
cast_from, cast_to));
&format!("converting from {0} to {1}, which causes a loss of precision \
({0} is {2} bits wide, but {1}'s mantissa is only {3} bits wide)",
cast_from, cast_to, from_nbits, if to_nbits == 64 {52} else {23} ));
}
}
},
(false, true) => {
span_lint(cx, CAST_POSSIBLE_OVERFLOW, expr.span,
&format!("the contents of a {} may overflow a {}", cast_from, cast_to));
span_lint(cx, CAST_POSSIBLE_TRUNCATION, expr.span,
&format!("casting {} to {} may cause truncation of the value", cast_from, cast_to));
if !cast_to.is_signed() {
span_lint(cx, CAST_SIGN_LOSS, expr.span,
&format!("casting from {} to {} loses the sign of the value", cast_from, cast_to));
@ -203,14 +204,14 @@ impl LintPass for CastPass {
};
if to_nbits < from_nbits ||
(!cast_from.is_signed() && cast_to.is_signed() && to_nbits <= from_nbits) {
span_lint(cx, CAST_POSSIBLE_OVERFLOW, expr.span,
&format!("the contents of a {} may overflow a {}", cast_from, cast_to));
span_lint(cx, CAST_POSSIBLE_TRUNCATION, expr.span,
&format!("casting {} to {} may cause truncation of the value", cast_from, cast_to));
}
}
(false, false) => {
if let (&ty::TyFloat(ast::TyF64),
&ty::TyFloat(ast::TyF32)) = (&cast_from.sty, &cast_to.sty) {
span_lint(cx, CAST_POSSIBLE_OVERFLOW, expr.span, "the contents of a f64 may overflow a f32");
span_lint(cx, CAST_POSSIBLE_TRUNCATION, expr.span, "casting f64 to f32 may cause truncation of the value");
}
}
}