Recover from semicolon field separator

Author: camsteffen

compiler/rustc_parse/src/parser/item.rs

@@ -1917,22 +1917,23 @@ impl<'a> Parser<'a> {
         attrs: AttrVec,
     ) -> PResult<'a, FieldDef> {
         let a_var = self.parse_name_and_ty(adt_ty, lo, vis, safety, attrs)?;
-        if self.eat(exp!(Semi)) {
-            let sp = self.prev_token.span;
-            let mut err =
-                self.dcx().struct_span_err(sp, format!("{adt_ty} fields are separated by `,`"));
-            err.span_suggestion_short(
-                sp,
-                "replace `;` with `,`",
-                ",",
-                Applicability::MachineApplicable,
-            );
-            return Err(err);
-        }
         match self.token.kind {
             token::Comma => {
                 self.bump();
             }
+            token::Semi => {
+                self.bump();
+                let sp = self.prev_token.span;
+                let mut err =
+                    self.dcx().struct_span_err(sp, format!("{adt_ty} fields are separated by `,`"));
+                err.span_suggestion_short(
+                    sp,
+                    "replace `;` with `,`",
+                    ",",
+                    Applicability::MachineApplicable,
+                );
+                err.emit();
+            }
             token::CloseBrace => {}
             token::DocComment(..) => {
                 let previous_span = self.prev_token.span;

tests/ui/parser/recover/recover-field-semi.rs

@@ -3,7 +3,7 @@ struct Foo {
     //~^ ERROR struct fields are separated by `,`
 }
 
-union Bar { //~ ERROR
+union Bar {
     foo: i32;
     //~^ ERROR union fields are separated by `,`
 }
@@ -13,4 +13,6 @@ enum Baz {
     //~^ ERROR struct fields are separated by `,`
 }
 
-fn main() {}
+fn main() {
+    let _ = Foo { foo: "" }; //~ ERROR mismatched types
+}

tests/ui/parser/recover/recover-field-semi.stderr

@@ -1,35 +1,27 @@
 error: struct fields are separated by `,`
   --> $DIR/recover-field-semi.rs:2:13
    |
-LL | struct Foo {
-   |        --- while parsing this struct
 LL |     foo: i32;
    |             ^ help: replace `;` with `,`
 
 error: union fields are separated by `,`
   --> $DIR/recover-field-semi.rs:7:13
    |
-LL | union Bar {
-   |       --- while parsing this union
 LL |     foo: i32;
    |             ^ help: replace `;` with `,`
 
 error: struct fields are separated by `,`
   --> $DIR/recover-field-semi.rs:12:19
    |
 LL |     Qux { foo: i32; }
-   |     ---           ^ help: replace `;` with `,`
-   |     |
-   |     while parsing this struct
+   |                   ^ help: replace `;` with `,`
 
-error: unions cannot have zero fields
-  --> $DIR/recover-field-semi.rs:6:1
+error[E0308]: mismatched types
+  --> $DIR/recover-field-semi.rs:17:24
    |
-LL | / union Bar {
-LL | |     foo: i32;
-LL | |
-LL | | }
-   | |_^
+LL |     let _ = Foo { foo: "" };
+   |                        ^^ expected `i32`, found `&str`
 
 error: aborting due to 4 previous errors
 
+For more information about this error, try `rustc --explain E0308`.

tests/ui/parser/removed-syntax/removed-syntax-field-semicolon.stderr

@@ -1,8 +1,6 @@
 error: struct fields are separated by `,`
   --> $DIR/removed-syntax-field-semicolon.rs:2:12
    |
-LL | struct S {
-   |        - while parsing this struct
 LL |     bar: ();
    |            ^ help: replace `;` with `,`
 

tests/ui/pattern/struct-parser-recovery-issue-126344.stderr

@@ -1,8 +1,6 @@
 error: struct fields are separated by `,`
   --> $DIR/struct-parser-recovery-issue-126344.rs:2:11
    |
-LL | struct Wrong {
-   |        ----- while parsing this struct
 LL |     x: i32;
    |           ^ help: replace `;` with `,`