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Change some helps to suggestions #31053

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Change some helps to suggestions #31053

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cb9e632
Add suggestion for negation of unsigned ints
Manishearth Jan 20, 2016
ffb670c
DRY for struct variant used, also use span_suggestion for E0423
Manishearth Jan 20, 2016
4a9a568
fix test
Manishearth Jan 20, 2016
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23 changes: 15 additions & 8 deletions src/librustc_lint/types.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -104,19 +104,19 @@ impl LateLintPass for TypeLimits {
if let hir::ExprLit(ref lit) = expr.node {
match lit.node {
ast::LitInt(_, ast::UnsignedIntLit(_)) => {
forbid_unsigned_negation(cx, e.span);
forbid_unsigned_negation(cx, e.span, lit.span);
},
ast::LitInt(_, ast::UnsuffixedIntLit(_)) => {
if let ty::TyUint(_) = cx.tcx.node_id_to_type(e.id).sty {
forbid_unsigned_negation(cx, e.span);
forbid_unsigned_negation(cx, e.span, lit.span);
}
},
_ => ()
}
} else {
let t = cx.tcx.node_id_to_type(expr.id);
if let ty::TyUint(_) = t.sty {
forbid_unsigned_negation(cx, e.span);
forbid_unsigned_negation(cx, e.span, expr.span);
}
}
// propagate negation, if the negation itself isn't negated
Expand Down Expand Up @@ -344,11 +344,18 @@ impl LateLintPass for TypeLimits {
}
}

fn forbid_unsigned_negation(cx: &LateContext, span: Span) {
cx.sess()
.struct_span_err_with_code(span, "unary negation of unsigned integer", "E0519")
.span_help(span, "use a cast or the `!` operator")
.emit();
fn forbid_unsigned_negation(cx: &LateContext, span: Span, lit_span: Span) {
let mut err = cx.sess()
.struct_span_err_with_code(span,
"unary negation of unsigned integer",
"E0519");
if let Ok(snip) = cx.sess().codemap().span_to_snippet(lit_span) {
err.span_suggestion(span, "try using a cast or the `!` operator:",
format!("!{}", snip));
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I think the cast way is the only one you can do generically. as -1isize as usize does not yield the same as !1usize. It would need to be !(x-1), which errors if x == 0

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Huh. Adding a generic cast here is harder so I'll just fix up the help message.

} else {
err.span_help(span, "use a cast or the `!` operator");
}
err.emit();
}
}
}
Expand Down
49 changes: 20 additions & 29 deletions src/librustc_resolve/lib.rs
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Expand Up @@ -420,12 +420,22 @@ fn resolve_struct_error<'b, 'a: 'b, 'tcx: 'a>(resolver: &'b Resolver<'a, 'tcx>,
name)
}
ResolutionError::StructVariantUsedAsFunction(path_name) => {
struct_span_err!(resolver.session,
span,
E0423,
"`{}` is the name of a struct or struct variant, but this expression \
uses it like a function name",
path_name)
let mut err = struct_span_err!(resolver.session,
span,
E0423,
"`{}` is the name of a struct or \
struct variant, but this expression \
uses it like a function name",
path_name);
if resolver.emit_errors {
let msg = format!("did you mean to write: `{} {{ /* fields */ }}`?",
path_name);
err.fileline_help(span, &msg);
} else {
let suggestion = format!("{} {{ /* fields */ }}", path_name);
err.span_suggestion(span, "did you mean to write", suggestion);
}
err
}
ResolutionError::SelfNotAvailableInStaticMethod => {
struct_span_err!(resolver.session,
Expand Down Expand Up @@ -3521,18 +3531,9 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
if let DefVariant(_, _, true) = path_res.base_def {
let path_name = path_names_to_string(path, 0);

let mut err = resolve_struct_error(self,
expr.span,
ResolutionError::StructVariantUsedAsFunction(&*path_name));
resolve_error(self, expr.span,
ResolutionError::StructVariantUsedAsFunction(&*path_name));

let msg = format!("did you mean to write: `{} {{ /* fields */ }}`?",
path_name);
if self.emit_errors {
err.fileline_help(expr.span, &msg);
} else {
err.span_help(expr.span, &msg);
}
err.emit();
self.record_def(expr.id, err_path_resolution());
} else {
// Write the result into the def map.
Expand Down Expand Up @@ -3562,18 +3563,8 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
self.record_def(expr.id, err_path_resolution());
match type_res.map(|r| r.base_def) {
Some(DefTy(struct_id, _)) if self.structs.contains_key(&struct_id) => {
let mut err = resolve_struct_error(self,
expr.span,
ResolutionError::StructVariantUsedAsFunction(&*path_name));

let msg = format!("did you mean to write: `{} {{ /* fields */ }}`?",
path_name);
if self.emit_errors {
err.fileline_help(expr.span, &msg);
} else {
err.span_help(expr.span, &msg);
}
err.emit();
resolve_error(self, expr.span,
ResolutionError::StructVariantUsedAsFunction(&*path_name));
}
_ => {
// Keep reporting some errors even if they're ignored above.
Expand Down
14 changes: 9 additions & 5 deletions src/test/compile-fail/feature-gate-negate-unsigned.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -18,25 +18,29 @@ impl std::ops::Neg for S {

const _MAX: usize = -1;
//~^ ERROR unary negation of unsigned integer
//~| HELP use a cast or the `!` operator
//~| HELP try using a cast or the `!` operator

fn main() {
let a = -1;
//~^ ERROR unary negation of unsigned integer
//~| HELP use a cast or the `!` operator
//~| HELP try using a cast or the `!` operator
//~| SUGGESTION let a = !1;
let _b : u8 = a; // for infering variable a to u8.

-a;
//~^ ERROR unary negation of unsigned integer
//~| HELP use a cast or the `!` operator
//~| HELP try using a cast or the `!` operator
//~| SUGGESTION !a

let _d = -1u8;
//~^ ERROR unary negation of unsigned integer
//~| HELP use a cast or the `!` operator
//~| HELP try using a cast or the `!` operator
//~| SUGGESTION let _d = !1u8;

for _ in -10..10u8 {}
//~^ ERROR unary negation of unsigned integer
//~| HELP use a cast or the `!` operator
//~| HELP try using a cast or the `!` operator
//~| SUGGESTION for _ in !10..10u8 {}

-S; // should not trigger the gate; issue 26840
}