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Rollup merge of #88757 - andrewhickman:master, r=jackh726

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Suggest wapping expr in parentheses on invalid unary negation

Fixes #88701
This commit is contained in:
Jubilee 2021-09-11 08:23:42 -07:00 committed by GitHub
commit 08cbb7dbe1
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GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 79 additions and 36 deletions
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79
compiler/rustc_typeck/src/check/op.rs
View File

@ -680,42 +680,53 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
ex.span,
format!("cannot apply unary operator `{}`", op.as_str()),
);
match actual.kind() {
Uint(_) if op == hir::UnOp::Neg => {
err.note("unsigned values cannot be negated");
if let hir::ExprKind::Unary(
_,
hir::Expr {
kind:
hir::ExprKind::Lit(Spanned {
node: ast::LitKind::Int(1, _),
..
}),
..
},
) = ex.kind
{
err.span_suggestion(
ex.span,
&format!(
"you may have meant the maximum value of `{}`",
actual
),
format!("{}::MAX", actual),
Applicability::MaybeIncorrect,
);
let sp = self.tcx.sess.source_map().start_point(ex.span);
if let Some(sp) =
self.tcx.sess.parse_sess.ambiguous_block_expr_parse.borrow().get(&sp)
{
// If the previous expression was a block expression, suggest parentheses
// (turning this into a binary subtraction operation instead.)
// for example, `{2} - 2` -> `({2}) - 2` (see src\test\ui\parser\expr-as-stmt.rs)
self.tcx.sess.parse_sess.expr_parentheses_needed(&mut err, *sp);
} else {
match actual.kind() {
Uint(_) if op == hir::UnOp::Neg => {
err.note("unsigned values cannot be negated");
if let hir::ExprKind::Unary(
_,
hir::Expr {
kind:
hir::ExprKind::Lit(Spanned {
node: ast::LitKind::Int(1, _),
..
}),
..
},
) = ex.kind
{
err.span_suggestion(
ex.span,
&format!(
"you may have meant the maximum value of `{}`",
actual
),
format!("{}::MAX", actual),
Applicability::MaybeIncorrect,
);
}
}
Str | Never | Char | Tuple(_) | Array(_, _) => {}
Ref(_, ref lty, _) if *lty.kind() == Str => {}
_ => {
let missing_trait = match op {
hir::UnOp::Neg => "std::ops::Neg",
hir::UnOp::Not => "std::ops::Not",
hir::UnOp::Deref => "std::ops::UnDerf",
};
suggest_impl_missing(&mut err, operand_ty, &missing_trait);
}
}
Str | Never | Char | Tuple(_) | Array(_, _) => {}
Ref(_, ref lty, _) if *lty.kind() == Str => {}
_ => {
let missing_trait = match op {
hir::UnOp::Neg => "std::ops::Neg",
hir::UnOp::Not => "std::ops::Not",
hir::UnOp::Deref => "std::ops::UnDerf",
};
suggest_impl_missing(&mut err, operand_ty, &missing_trait);
}
}
err.emit();

5
src/test/ui/parser/expr-as-stmt.fixed
View File

@ -32,4 +32,9 @@ fn moo(x: u32) -> bool {
}) > 0 //~ ERROR expected expression
}
fn qux() -> u32 {
({2}) - 2 //~ ERROR cannot apply unary operator `-` to type `u32`
//~^ ERROR mismatched types
}
fn main() {}

5
src/test/ui/parser/expr-as-stmt.rs
View File

@ -32,4 +32,9 @@ fn moo(x: u32) -> bool {
} > 0 //~ ERROR expected expression
}
fn qux() -> u32 {
{2} - 2 //~ ERROR cannot apply unary operator `-` to type `u32`
//~^ ERROR mismatched types
}
fn main() {}

26
src/test/ui/parser/expr-as-stmt.stderr
View File

@ -99,7 +99,29 @@ help: parentheses are required to parse this as an expression
LL | ({ 3 }) * 3
| + +
error: aborting due to 9 previous errors
error[E0308]: mismatched types
--> $DIR/expr-as-stmt.rs:36:6
|
LL | {2} - 2
| ^ expected `()`, found integer
|
help: you might have meant to return this value
|
LL | {return 2;} - 2
| ++++++ +
Some errors have detailed explanations: E0308, E0614.
error[E0600]: cannot apply unary operator `-` to type `u32`
--> $DIR/expr-as-stmt.rs:36:9
|
LL | {2} - 2
| ^^^ cannot apply unary operator `-`
|
help: parentheses are required to parse this as an expression
|
LL | ({2}) - 2
| + +
error: aborting due to 11 previous errors
Some errors have detailed explanations: E0308, E0600, E0614.
For more information about an error, try `rustc --explain E0308`.