Rollup merge of #130725 - GrigorenkoPV:@-in-struct-patterns, r=Nadrieril

Parser: better error messages for `@` in struct patterns

2 files changed, 83 insertions, 0 deletions

diff --git a/tests/ui/pattern/at-in-struct-patterns.rs b/tests/ui/pattern/at-in-struct-patterns.rs
new file mode 100644
index 00000000000..e8fad61f317
--- /dev/null
+++ b/tests/ui/pattern/at-in-struct-patterns.rs
@@ -0,0 +1,14 @@
+struct Foo {
+    field1: u8,
+    field2: u8,
+}
+
+fn main() {
+    let foo = Foo { field1: 1, field2: 2 };
+    let Foo { var @ field1, .. } = foo; //~ ERROR Unexpected `@` in struct pattern
+    dbg!(var); //~ ERROR cannot find value `var` in this scope
+    let Foo { field1: _, bar @ .. } = foo; //~ ERROR `@ ..` is not supported in struct patterns
+    let Foo { bar @ .. } = foo; //~ ERROR `@ ..` is not supported in struct patterns
+    let Foo { @ } = foo; //~ ERROR expected identifier, found `@`
+    let Foo { @ .. } = foo; //~ ERROR expected identifier, found `@`
+}
diff --git a/tests/ui/pattern/at-in-struct-patterns.stderr b/tests/ui/pattern/at-in-struct-patterns.stderr
new file mode 100644
index 00000000000..ff75edfe681
--- /dev/null
+++ b/tests/ui/pattern/at-in-struct-patterns.stderr
@@ -0,0 +1,69 @@
+error: Unexpected `@` in struct pattern
+  --> $DIR/at-in-struct-patterns.rs:8:15
+   |
+LL |     let Foo { var @ field1, .. } = foo;
+   |         ---   ^^^^^
+   |         |
+   |         while parsing the fields for this pattern
+   |
+   = note: struct patterns use `field: pattern` syntax to bind to fields
+   = help: consider replacing `new_name @ field_name` with `field_name: new_name` if that is what you intended
+
+error: `@ ..` is not supported in struct patterns
+  --> $DIR/at-in-struct-patterns.rs:10:26
+   |
+LL |     let Foo { field1: _, bar @ .. } = foo;
+   |         ---              ^^^^^^^^
+   |         |
+   |         while parsing the fields for this pattern
+   |
+help: bind to each field separately or, if you don't need them, just remove `bar @`
+   |
+LL -     let Foo { field1: _, bar @ .. } = foo;
+LL +     let Foo { field1: _, .. } = foo;
+   |
+
+error: `@ ..` is not supported in struct patterns
+  --> $DIR/at-in-struct-patterns.rs:11:15
+   |
+LL |     let Foo { bar @ .. } = foo;
+   |         ---   ^^^^^^^^
+   |         |
+   |         while parsing the fields for this pattern
+   |
+help: bind to each field separately or, if you don't need them, just remove `bar @`
+   |
+LL -     let Foo { bar @ .. } = foo;
+LL +     let Foo { .. } = foo;
+   |
+
+error: expected identifier, found `@`
+  --> $DIR/at-in-struct-patterns.rs:12:15
+   |
+LL |     let Foo { @ } = foo;
+   |         ---   ^ expected identifier
+   |         |
+   |         while parsing the fields for this pattern
+
+error: expected identifier, found `@`
+  --> $DIR/at-in-struct-patterns.rs:13:15
+   |
+LL |     let Foo { @ .. } = foo;
+   |         ---   ^ expected identifier
+   |         |
+   |         while parsing the fields for this pattern
+
+error[E0425]: cannot find value `var` in this scope
+  --> $DIR/at-in-struct-patterns.rs:9:10
+   |
+LL |     dbg!(var);
+   |          ^^^ not found in this scope
+   |
+help: consider importing this function
+   |
+LL + use std::env::var;
+   |
+
+error: aborting due to 6 previous errors
+
+For more information about this error, try `rustc --explain E0425`.