Tweak incorrect discriminator value variant error

Author: estebank

src/libsyntax/parse/parser.rs

@@ -6983,7 +6983,7 @@ impl<'a> Parser<'a> {
     fn parse_enum_def(&mut self, _generics: &ast::Generics) -> PResult<'a, EnumDef> {
         let mut variants = Vec::new();
         let mut all_nullary = true;
-        let mut any_disr = None;
+        let mut any_disr = vec![];
         while self.token != token::CloseDelim(token::Brace) {
             let variant_attrs = self.parse_outer_attributes()?;
             let vlo = self.span;
@@ -7005,7 +7005,9 @@ impl<'a> Parser<'a> {
                     id: ast::DUMMY_NODE_ID,
                     value: self.parse_expr()?,
                 });
-                any_disr = disr_expr.as_ref().map(|c| c.value.span);
+                if let Some(sp) = disr_expr.as_ref().map(|c| c.value.span) {
+                    any_disr.push(sp);
+                }
                 struct_def = VariantData::Unit(ast::DUMMY_NODE_ID);
             } else {
                 struct_def = VariantData::Unit(ast::DUMMY_NODE_ID);
@@ -7022,11 +7024,15 @@ impl<'a> Parser<'a> {
             if !self.eat(&token::Comma) { break; }
         }
         self.expect(&token::CloseDelim(token::Brace))?;
-        match any_disr {
-            Some(disr_span) if !all_nullary =>
-                self.span_err(disr_span,
-                    "discriminator values can only be used with a field-less enum"),
-            _ => ()
+        if !any_disr.is_empty() && !all_nullary {
+            let mut err =self.struct_span_err(
+                any_disr.clone(),
+                "discriminator values can only be used with a field-less enum",
+            );
+            for sp in any_disr {
+                err.span_label(sp, "only valid in field-less enums");
+            }
+            err.emit();
         }
 
         Ok(ast::EnumDef { variants })

src/test/ui/parser/issue-17383.rs

@@ -1,8 +1,7 @@
 enum X {
-    A =
-        b'a' //~ ERROR discriminator values can only be used with a field-less enum
-    ,
-    B(isize)
+    A = 3,
+    //~^ ERROR discriminator values can only be used with a field-less enum
+    B(usize)
 }
 
 fn main() {}

src/test/ui/parser/issue-17383.stderr

@@ -1,8 +1,8 @@
 error: discriminator values can only be used with a field-less enum
-  --> $DIR/issue-17383.rs:3:9
+  --> $DIR/issue-17383.rs:2:9
    |
-LL |         b'a' //~ ERROR discriminator values can only be used with a field-less enum
-   |         ^^^^
+LL |     A = 3,
+   |         ^ only valid in field-less enums
 
 error: aborting due to previous error
 

src/test/ui/parser/tag-variant-disr-non-nullary.rs

@@ -1,12 +1,14 @@
-//error-pattern: discriminator values can only be used with a field-less enum
 
-enum color {
-    red = 0xff0000,
-    green = 0x00ff00,
-    blue = 0x0000ff,
-    black = 0x000000,
-    white = 0xffffff,
-    other (str),
+enum Color {
+    Red = 0xff0000,
+    //~^ ERROR discriminator values can only be used with a field-less enum
+    Green = 0x00ff00,
+    Blue = 0x0000ff,
+    Black = 0x000000,
+    White = 0xffffff,
+    Other (str),
+    //~^ ERROR the size for values of type
+    // the above is kept in order to verify that we get beyond parse errors
 }
 
 fn main() {}

src/test/ui/parser/tag-variant-disr-non-nullary.stderr

@@ -1,8 +1,28 @@
 error: discriminator values can only be used with a field-less enum
-  --> $DIR/tag-variant-disr-non-nullary.rs:8:13
+  --> $DIR/tag-variant-disr-non-nullary.rs:3:11
    |
-LL |     white = 0xffffff,
-   |             ^^^^^^^^
+LL |     Red = 0xff0000,
+   |           ^^^^^^^^ only valid in field-less enums
+LL |     //~^ ERROR discriminator values can only be used with a field-less enum
+LL |     Green = 0x00ff00,
+   |             ^^^^^^^^ only valid in field-less enums
+LL |     Blue = 0x0000ff,
+   |            ^^^^^^^^ only valid in field-less enums
+LL |     Black = 0x000000,
+   |             ^^^^^^^^ only valid in field-less enums
+LL |     White = 0xffffff,
+   |             ^^^^^^^^ only valid in field-less enums
 
-error: aborting due to previous error
+error[E0277]: the size for values of type `str` cannot be known at compilation time
+  --> $DIR/tag-variant-disr-non-nullary.rs:9:12
+   |
+LL |     Other (str),
+   |            ^^^ doesn't have a size known at compile-time
+   |
+   = help: the trait `std::marker::Sized` is not implemented for `str`
+   = note: to learn more, visit <https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
+   = note: no field of an enum variant may have a dynamically sized type
+
+error: aborting due to 2 previous errors
 
+For more information about this error, try `rustc --explain E0277`.