rust/tests/ui/empty/empty-struct-unit-expr.rs

// Can't use unit struct as constructor function

//@ aux-build:empty-struct.rs

extern crate empty_struct;
use empty_struct::*;

struct Empty2;

enum E {
    Empty4
}

fn main() {
    let e2 = Empty2(); //~ ERROR expected function, found struct `Empty2`
    let e4 = E::Empty4();
    //~^ ERROR expected function, found enum variant `E::Empty4` [E0618]
    let xe2 = XEmpty2(); //~ ERROR expected function, found struct `XEmpty2`
    let xe4 = XE::XEmpty4();
    //~^ ERROR expected function, found enum variant `XE::XEmpty4` [E0618]
}
Test and gate empty structures and variants better 2015-10-02 19:41:24 +00:00			`// Can't use unit struct as constructor function`
Return nonzero exit code if there are errors at a stop point 2015-02-09 19:01:45 +00:00
Preserve struct/variant kinds in metadata Add tests for use of empty structs in cross-crate scenarios 2016-01-14 11:26:50 +00:00			`//@ aux-build:empty-struct.rs`

			`extern crate empty_struct;`
			`use empty_struct::*;`

			`struct Empty2;`
Test and gate empty structures and variants better 2015-10-02 19:41:24 +00:00
			`enum E {`
Preserve struct/variant kinds in metadata Add tests for use of empty structs in cross-crate scenarios 2016-01-14 11:26:50 +00:00			`Empty4`
Test and gate empty structures and variants better 2015-10-02 19:41:24 +00:00			`}`
Add parse-error recovery for erroneous `struct_id { }` form. There are 4 different new tests, to check some different scenarios for what the parse context is at the time of recovery, becasue our compile-fail infrastructure does not appear to handle verifying error-recovery situations. Differentiate between unit-like struct definition item and unit-like struct construction in the error message. ---- More generally, outlines a more generic strategy for parse error recovery: By committing to an expression/statement at set points in the parser, we can then do some look-ahead to catch common mistakes and skip over them. One detail about this strategy is that you want to avoid emitting the "helpful" message unless the input is reasonably close to the case of interest. (E.g. do not warn about a potential unit struct for an input of the form `let hmm = do foo { } { };`) To accomplish this, I added (partial) last_token tracking; used for `commit_stmt` support. The check_for_erroneous_unit_struct_expecting fn returns bool to signal whether it "made progress"; currently unused; this is meant for use to compose several such recovery checks together in a loop. 2013-08-05 20:18:29 +00:00
Implement empty struct with braces (RFC 218) 2015-09-10 19:46:52 +00:00			`fn main() {`
Be more precise when suggesting removal of parens on unit adt ctor 2022-07-16 22:15:41 +00:00			let e2 = Empty2(); //~ ERROR expected function, found struct `Empty2`
Reword error when data-less enum variant called as function Given a file like: ```rust enum Test { Variant, Variant2 {a: u32}, } fn main(){ let x = Test::Variant("Hello"); let y = Test::Variant2("World"); } ``` The errors now look this way: ```bash error[E0423]: `Test::Variant2` is the name of a struct or struct variant, but this expression uses it like a function name --> file3.rs:10:13 \| 10 \| let y = Test::Variant2("Hello"); \| ^^^^^^^^^^^^^^ struct called like a function \| = help: did you mean to write: `Test::Variant2 { /* fields */ }`? error: `Test::Variant` is being called, but it is not a function --> file3.rs:9:13 \| 9 \| let x = Test::Variant("World"); \| ^^^^^^^^^^^^^^^^^^^^^^ \| = help: did you mean to write: `Test::Variant`? note: defined here --> file3.rs:2:5 \| 2 \| Variant, \| ^^^^^^^ error: aborting due to previous error ``` 2016-09-13 05:11:05 +00:00			`let e4 = E::Empty4();`
Further tweaks to the output - Properly address Variant Ctors - Show signature if span of trait method without `self` is not available 2018-01-15 13:18:06 +00:00			//~^ ERROR expected function, found enum variant `E::Empty4` [E0618]
Be more precise when suggesting removal of parens on unit adt ctor 2022-07-16 22:15:41 +00:00			let xe2 = XEmpty2(); //~ ERROR expected function, found struct `XEmpty2`
Reword error when data-less enum variant called as function Given a file like: ```rust enum Test { Variant, Variant2 {a: u32}, } fn main(){ let x = Test::Variant("Hello"); let y = Test::Variant2("World"); } ``` The errors now look this way: ```bash error[E0423]: `Test::Variant2` is the name of a struct or struct variant, but this expression uses it like a function name --> file3.rs:10:13 \| 10 \| let y = Test::Variant2("Hello"); \| ^^^^^^^^^^^^^^ struct called like a function \| = help: did you mean to write: `Test::Variant2 { /* fields */ }`? error: `Test::Variant` is being called, but it is not a function --> file3.rs:9:13 \| 9 \| let x = Test::Variant("World"); \| ^^^^^^^^^^^^^^^^^^^^^^ \| = help: did you mean to write: `Test::Variant`? note: defined here --> file3.rs:2:5 \| 2 \| Variant, \| ^^^^^^^ error: aborting due to previous error ``` 2016-09-13 05:11:05 +00:00			`let xe4 = XE::XEmpty4();`
Further tweaks to the output - Properly address Variant Ctors - Show signature if span of trait method without `self` is not available 2018-01-15 13:18:06 +00:00			//~^ ERROR expected function, found enum variant `XE::XEmpty4` [E0618]
Add parse-error recovery for erroneous `struct_id { }` form. There are 4 different new tests, to check some different scenarios for what the parse context is at the time of recovery, becasue our compile-fail infrastructure does not appear to handle verifying error-recovery situations. Differentiate between unit-like struct definition item and unit-like struct construction in the error message. ---- More generally, outlines a more generic strategy for parse error recovery: By committing to an expression/statement at set points in the parser, we can then do some look-ahead to catch common mistakes and skip over them. One detail about this strategy is that you want to avoid emitting the "helpful" message unless the input is reasonably close to the case of interest. (E.g. do not warn about a potential unit struct for an input of the form `let hmm = do foo { } { };`) To accomplish this, I added (partial) last_token tracking; used for `commit_stmt` support. The check_for_erroneous_unit_struct_expecting fn returns bool to signal whether it "made progress"; currently unused; this is meant for use to compose several such recovery checks together in a loop. 2013-08-05 20:18:29 +00:00			`}`