diff options
Diffstat (limited to 'src/tools/clippy/tests/ui/needless_lifetimes.rs')
-rw-r--r-- | src/tools/clippy/tests/ui/needless_lifetimes.rs | 96 |
1 files changed, 86 insertions, 10 deletions
diff --git a/src/tools/clippy/tests/ui/needless_lifetimes.rs b/src/tools/clippy/tests/ui/needless_lifetimes.rs index fc686b1da..2efc93675 100644 --- a/src/tools/clippy/tests/ui/needless_lifetimes.rs +++ b/src/tools/clippy/tests/ui/needless_lifetimes.rs @@ -29,11 +29,20 @@ fn multiple_in_and_out_1<'a>(x: &'a u8, _y: &'a u8) -> &'a u8 { x } -// No error; multiple input refs. -fn multiple_in_and_out_2<'a, 'b>(x: &'a u8, _y: &'b u8) -> &'a u8 { +// Error; multiple input refs, but the output lifetime is not elided, i.e., the following is valid: +// fn multiple_in_and_out_2a<'a>(x: &'a u8, _y: &u8) -> &'a u8 +// ^^^ +fn multiple_in_and_out_2a<'a, 'b>(x: &'a u8, _y: &'b u8) -> &'a u8 { x } +// Error; multiple input refs, but the output lifetime is not elided, i.e., the following is valid: +// fn multiple_in_and_out_2b<'b>(_x: &u8, y: &'b u8) -> &'b u8 +// ^^^ +fn multiple_in_and_out_2b<'a, 'b>(_x: &'a u8, y: &'b u8) -> &'b u8 { + y +} + // No error; multiple input refs async fn func<'a>(args: &[&'a str]) -> Option<&'a str> { args.get(0).cloned() @@ -44,11 +53,20 @@ fn in_static_and_out<'a>(x: &'a u8, _y: &'static u8) -> &'a u8 { x } -// No error. -fn deep_reference_1<'a, 'b>(x: &'a u8, _y: &'b u8) -> Result<&'a u8, ()> { +// Error; multiple input refs, but the output lifetime is not elided, i.e., the following is valid: +// fn deep_reference_1a<'a>(x: &'a u8, _y: &u8) -> Result<&'a u8, ()> +// ^^^ +fn deep_reference_1a<'a, 'b>(x: &'a u8, _y: &'b u8) -> Result<&'a u8, ()> { Ok(x) } +// Error; multiple input refs, but the output lifetime is not elided, i.e., the following is valid: +// fn deep_reference_1b<'b>(_x: &u8, y: &'b u8) -> Result<&'b u8, ()> +// ^^^ +fn deep_reference_1b<'a, 'b>(_x: &'a u8, y: &'b u8) -> Result<&'b u8, ()> { + Ok(y) +} + // No error; two input refs. fn deep_reference_2<'a>(x: Result<&'a u8, &'a u8>) -> &'a u8 { x.unwrap() @@ -129,11 +147,20 @@ impl X { &self.x } - // No error; multiple input refs. - fn self_and_in_out<'s, 't>(&'s self, _x: &'t u8) -> &'s u8 { + // Error; multiple input refs, but the output lifetime is not elided, i.e., the following is valid: + // fn self_and_in_out_1<'s>(&'s self, _x: &u8) -> &'s u8 + // ^^^ + fn self_and_in_out_1<'s, 't>(&'s self, _x: &'t u8) -> &'s u8 { &self.x } + // Error; multiple input refs, but the output lifetime is not elided, i.e., the following is valid: + // fn self_and_in_out_2<'t>(&self, x: &'t u8) -> &'t u8 + // ^^^^^ + fn self_and_in_out_2<'s, 't>(&'s self, x: &'t u8) -> &'t u8 { + x + } + fn distinct_self_and_in<'s, 't>(&'s self, _x: &'t u8) {} // No error; same lifetimes on two params. @@ -167,8 +194,19 @@ fn struct_with_lt3<'a>(_foo: &Foo<'a>) -> &'a str { unimplemented!() } -// No warning; two input lifetimes. -fn struct_with_lt4<'a, 'b>(_foo: &'a Foo<'b>) -> &'a str { +// Warning; two input lifetimes, but the output lifetime is not elided, i.e., the following is +// valid: +// fn struct_with_lt4a<'a>(_foo: &'a Foo<'_>) -> &'a str +// ^^ +fn struct_with_lt4a<'a, 'b>(_foo: &'a Foo<'b>) -> &'a str { + unimplemented!() +} + +// Warning; two input lifetimes, but the output lifetime is not elided, i.e., the following is +// valid: +// fn struct_with_lt4b<'b>(_foo: &Foo<'b>) -> &'b str +// ^^^^ +fn struct_with_lt4b<'a, 'b>(_foo: &'a Foo<'b>) -> &'b str { unimplemented!() } @@ -203,8 +241,19 @@ fn alias_with_lt3<'a>(_foo: &FooAlias<'a>) -> &'a str { unimplemented!() } -// No warning; two input lifetimes. -fn alias_with_lt4<'a, 'b>(_foo: &'a FooAlias<'b>) -> &'a str { +// Warning; two input lifetimes, but the output lifetime is not elided, i.e., the following is +// valid: +// fn alias_with_lt4a<'a>(_foo: &'a FooAlias<'_>) -> &'a str +// ^^ +fn alias_with_lt4a<'a, 'b>(_foo: &'a FooAlias<'b>) -> &'a str { + unimplemented!() +} + +// Warning; two input lifetimes, but the output lifetime is not elided, i.e., the following is +// valid: +// fn alias_with_lt4b<'b>(_foo: &FooAlias<'b>) -> &'b str +// ^^^^^^^^^ +fn alias_with_lt4b<'a, 'b>(_foo: &'a FooAlias<'b>) -> &'b str { unimplemented!() } @@ -419,4 +468,31 @@ mod issue7296 { } } +mod pr_9743_false_negative_fix { + #![allow(unused)] + + fn foo<'a>(x: &'a u8, y: &'_ u8) {} + + fn bar<'a>(x: &'a u8, y: &'_ u8, z: &'_ u8) {} +} + +mod pr_9743_output_lifetime_checks { + #![allow(unused)] + + // lint: only one input + fn one_input<'a>(x: &'a u8) -> &'a u8 { + unimplemented!() + } + + // lint: multiple inputs, output would not be elided + fn multiple_inputs_output_not_elided<'a, 'b>(x: &'a u8, y: &'b u8, z: &'b u8) -> &'b u8 { + unimplemented!() + } + + // don't lint: multiple inputs, output would be elided (which would create an ambiguity) + fn multiple_inputs_output_would_be_elided<'a, 'b>(x: &'a u8, y: &'b u8, z: &'b u8) -> &'a u8 { + unimplemented!() + } +} + fn main() {} |