From 21f8326cec03848368e02936a032103aa24cf6d2 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Esteban=20K=C3=BCber?= Date: Fri, 11 Sep 2020 13:47:33 -0700 Subject: [PATCH] Provide suggestion for missing fields in patterns --- compiler/rustc_typeck/src/check/pat.rs | 58 ++++++++++++++++--- src/test/ui/error-codes/E0027-teach.rs | 15 ----- src/test/ui/error-codes/E0027-teach.stderr | 11 ---- src/test/ui/error-codes/E0027.rs | 6 +- src/test/ui/error-codes/E0027.stderr | 26 ++++++++- src/test/ui/structs/struct-field-cfg.stderr | 9 +++ .../structs/struct-pat-derived-error.stderr | 9 +++ 7 files changed, 96 insertions(+), 38 deletions(-) delete mode 100644 src/test/ui/error-codes/E0027-teach.rs delete mode 100644 src/test/ui/error-codes/E0027-teach.stderr diff --git a/compiler/rustc_typeck/src/check/pat.rs b/compiler/rustc_typeck/src/check/pat.rs index 1896155e327..bae0a7e611a 100644 --- a/compiler/rustc_typeck/src/check/pat.rs +++ b/compiler/rustc_typeck/src/check/pat.rs @@ -1121,7 +1121,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { if no_accessible_unmentioned_fields { unmentioned_err = Some(self.error_no_accessible_fields(pat, &fields)); } else { - unmentioned_err = Some(self.error_unmentioned_fields(pat, &unmentioned_fields)); + unmentioned_err = + Some(self.error_unmentioned_fields(pat, &unmentioned_fields, &fields)); } } match (inexistent_fields_err, unmentioned_err) { @@ -1376,6 +1377,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { &self, pat: &Pat<'_>, unmentioned_fields: &[(&ty::FieldDef, Ident)], + fields: &'tcx [hir::FieldPat<'tcx>], ) -> DiagnosticBuilder<'tcx> { let field_names = if unmentioned_fields.len() == 1 { format!("field `{}`", unmentioned_fields[0].1) @@ -1395,14 +1397,52 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { field_names ); err.span_label(pat.span, format!("missing {}", field_names)); - if self.tcx.sess.teach(&err.get_code().unwrap()) { - err.note( - "This error indicates that a pattern for a struct fails to specify a \ - sub-pattern for every one of the struct's fields. Ensure that each field \ - from the struct's definition is mentioned in the pattern, or use `..` to \ - ignore unwanted fields.", - ); - } + let len = unmentioned_fields.len(); + let (prefix, postfix, sp) = match fields { + [] => match &pat.kind { + PatKind::Struct(path, [], false) => { + (" { ", " }", path.span().shrink_to_hi().until(pat.span.shrink_to_hi())) + } + _ => return err, + }, + [.., field] => ( + match pat.kind { + PatKind::Struct(_, [_, ..], _) => ", ", + _ => "", + }, + "", + field.span.shrink_to_hi(), + ), + }; + err.span_suggestion( + sp, + &format!( + "include the missing field{} in the pattern", + if len == 1 { "" } else { "s" }, + ), + format!( + "{}{}{}", + prefix, + unmentioned_fields + .iter() + .map(|(_, name)| name.to_string()) + .collect::>() + .join(", "), + postfix, + ), + Applicability::MachineApplicable, + ); + err.span_suggestion( + sp, + &format!( + "if you don't care about {} missing field{}, you can explicitely ignore {}", + if len == 1 { "this" } else { "these" }, + if len == 1 { "" } else { "s" }, + if len == 1 { "it" } else { "them" }, + ), + format!("{}..{}", prefix, postfix), + Applicability::MachineApplicable, + ); err } diff --git a/src/test/ui/error-codes/E0027-teach.rs b/src/test/ui/error-codes/E0027-teach.rs deleted file mode 100644 index 11402f01484..00000000000 --- a/src/test/ui/error-codes/E0027-teach.rs +++ /dev/null @@ -1,15 +0,0 @@ -// compile-flags: -Z teach - -struct Dog { - name: String, - age: u32, -} - -fn main() { - let d = Dog { name: "Rusty".to_string(), age: 8 }; - - match d { - Dog { age: x } => {} - //~^ ERROR pattern does not mention field `name` - } -} diff --git a/src/test/ui/error-codes/E0027-teach.stderr b/src/test/ui/error-codes/E0027-teach.stderr deleted file mode 100644 index aa4cb9d4d18..00000000000 --- a/src/test/ui/error-codes/E0027-teach.stderr +++ /dev/null @@ -1,11 +0,0 @@ -error[E0027]: pattern does not mention field `name` - --> $DIR/E0027-teach.rs:12:9 - | -LL | Dog { age: x } => {} - | ^^^^^^^^^^^^^^ missing field `name` - | - = note: This error indicates that a pattern for a struct fails to specify a sub-pattern for every one of the struct's fields. Ensure that each field from the struct's definition is mentioned in the pattern, or use `..` to ignore unwanted fields. - -error: aborting due to previous error - -For more information about this error, try `rustc --explain E0027`. diff --git a/src/test/ui/error-codes/E0027.rs b/src/test/ui/error-codes/E0027.rs index b8c6a2b7fcd..8d08e178934 100644 --- a/src/test/ui/error-codes/E0027.rs +++ b/src/test/ui/error-codes/E0027.rs @@ -7,7 +7,9 @@ fn main() { let d = Dog { name: "Rusty".to_string(), age: 8 }; match d { - Dog { age: x } => {} - //~^ ERROR pattern does not mention field `name` + Dog { age: x } => {} //~ ERROR pattern does not mention field `name` + } + match d { + Dog {} => {} //~ ERROR pattern does not mention fields `name`, `age` } } diff --git a/src/test/ui/error-codes/E0027.stderr b/src/test/ui/error-codes/E0027.stderr index 4f17bba6477..c09f1ff1f2a 100644 --- a/src/test/ui/error-codes/E0027.stderr +++ b/src/test/ui/error-codes/E0027.stderr @@ -3,7 +3,31 @@ error[E0027]: pattern does not mention field `name` | LL | Dog { age: x } => {} | ^^^^^^^^^^^^^^ missing field `name` + | +help: include the missing field in the pattern + | +LL | Dog { age: x, name } => {} + | ^^^^^^ +help: if you don't care about this missing field, you can explicitely ignore it + | +LL | Dog { age: x, .. } => {} + | ^^^^ -error: aborting due to previous error +error[E0027]: pattern does not mention fields `name`, `age` + --> $DIR/E0027.rs:13:9 + | +LL | Dog {} => {} + | ^^^^^^ missing fields `name`, `age` + | +help: include the missing fields in the pattern + | +LL | Dog { name, age } => {} + | ^^^^^^^^^^^^^ +help: if you don't care about these missing fields, you can explicitely ignore them + | +LL | Dog { .. } => {} + | ^^^^^^ + +error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0027`. diff --git a/src/test/ui/structs/struct-field-cfg.stderr b/src/test/ui/structs/struct-field-cfg.stderr index 29bad31ef96..b913b929079 100644 --- a/src/test/ui/structs/struct-field-cfg.stderr +++ b/src/test/ui/structs/struct-field-cfg.stderr @@ -17,6 +17,15 @@ error[E0027]: pattern does not mention field `present` | LL | let Foo { #[cfg(any())] present: () } = foo; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ missing field `present` + | +help: include the missing field in the pattern + | +LL | let Foo { present } = foo; + | ^^^^^^^^^^^ +help: if you don't care about this missing field, you can explicitely ignore it + | +LL | let Foo { .. } = foo; + | ^^^^^^ error[E0026]: struct `Foo` does not have a field named `absent` --> $DIR/struct-field-cfg.rs:16:42 diff --git a/src/test/ui/structs/struct-pat-derived-error.stderr b/src/test/ui/structs/struct-pat-derived-error.stderr index 6526ef58a44..f3e9ce76f1e 100644 --- a/src/test/ui/structs/struct-pat-derived-error.stderr +++ b/src/test/ui/structs/struct-pat-derived-error.stderr @@ -15,6 +15,15 @@ error[E0027]: pattern does not mention fields `b`, `c` | LL | let A { x, y } = self.d; | ^^^^^^^^^^ missing fields `b`, `c` + | +help: include the missing fields in the pattern + | +LL | let A { x, y, b, c } = self.d; + | ^^^^^^ +help: if you don't care about these missing fields, you can explicitely ignore them + | +LL | let A { x, y, .. } = self.d; + | ^^^^ error: aborting due to 3 previous errors