bjoernager/rust
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better suggestion for duplicated where

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This commit is contained in:
Michael Goulet 2022-02-01 21:44:44 -08:00
parent 1ea4851715
commit f35d43cdf0
6 changed files with 147 additions and 9 deletions
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18
compiler/rustc_parse/src/parser/generics.rs
View file

@ -4,7 +4,7 @@ use rustc_ast::token;
use rustc_ast::{
self as ast, Attribute, GenericBounds, GenericParam, GenericParamKind, WhereClause,
};
use rustc_errors::PResult;
use rustc_errors::{Applicability, PResult};
use rustc_span::symbol::kw;
impl<'a> Parser<'a> {
@ -256,7 +256,21 @@ impl<'a> Parser<'a> {
break;
}
if !self.eat(&token::Comma) {
let prev_token = self.prev_token.span;
let ate_comma = self.eat(&token::Comma);
if self.eat_keyword_noexpect(kw::Where) {
let msg = &format!("cannot define duplicate `where` clauses on an item");
let mut err = self.struct_span_err(self.token.span, msg);
err.span_label(lo, "previous `where` clause starts here");
err.span_suggestion_verbose(
prev_token.shrink_to_hi().to(self.prev_token.span),
"consider joining the two `where` clauses into one",
",".to_owned(),
Applicability::MaybeIncorrect,
);
err.emit();
} else if !ate_comma {
break;
}
}

29
compiler/rustc_parse/src/parser/item.rs
View file

@ -1221,7 +1221,7 @@ impl<'a> Parser<'a> {
let struct_def = if this.check(&token::OpenDelim(token::Brace)) {
// Parse a struct variant.
let (fields, recovered) = this.parse_record_struct_body("struct")?;
let (fields, recovered) = this.parse_record_struct_body("struct", false)?;
VariantData::Struct(fields, recovered)
} else if this.check(&token::OpenDelim(token::Paren)) {
VariantData::Tuple(this.parse_tuple_struct_body()?, DUMMY_NODE_ID)
@ -1275,7 +1275,8 @@ impl<'a> Parser<'a> {
VariantData::Unit(DUMMY_NODE_ID)
} else {
// If we see: `struct Foo<T> where T: Copy { ... }`
let (fields, recovered) = self.parse_record_struct_body("struct")?;
let (fields, recovered) =
self.parse_record_struct_body("struct", generics.where_clause.has_where_token)?;
VariantData::Struct(fields, recovered)
}
// No `where` so: `struct Foo<T>;`
@ -1283,7 +1284,8 @@ impl<'a> Parser<'a> {
VariantData::Unit(DUMMY_NODE_ID)
// Record-style struct definition
} else if self.token == token::OpenDelim(token::Brace) {
let (fields, recovered) = self.parse_record_struct_body("struct")?;
let (fields, recovered) =
self.parse_record_struct_body("struct", generics.where_clause.has_where_token)?;
VariantData::Struct(fields, recovered)
// Tuple-style struct definition with optional where-clause.
} else if self.token == token::OpenDelim(token::Paren) {
@ -1313,10 +1315,12 @@ impl<'a> Parser<'a> {
let vdata = if self.token.is_keyword(kw::Where) {
generics.where_clause = self.parse_where_clause()?;
let (fields, recovered) = self.parse_record_struct_body("union")?;
let (fields, recovered) =
self.parse_record_struct_body("union", generics.where_clause.has_where_token)?;
VariantData::Struct(fields, recovered)
} else if self.token == token::OpenDelim(token::Brace) {
let (fields, recovered) = self.parse_record_struct_body("union")?;
let (fields, recovered) =
self.parse_record_struct_body("union", generics.where_clause.has_where_token)?;
VariantData::Struct(fields, recovered)
} else {
let token_str = super::token_descr(&self.token);
@ -1332,6 +1336,7 @@ impl<'a> Parser<'a> {
fn parse_record_struct_body(
&mut self,
adt_ty: &str,
parsed_where: bool,
) -> PResult<'a, (Vec<FieldDef>, /* recovered */ bool)> {
let mut fields = Vec::new();
let mut recovered = false;
@ -1353,9 +1358,19 @@ impl<'a> Parser<'a> {
self.eat(&token::CloseDelim(token::Brace));
} else {
let token_str = super::token_descr(&self.token);
let msg = &format!("expected `where`, or `{{` after struct name, found {}", token_str);
let msg = &format!(
"expected {}`{{` after struct name, found {}",
if parsed_where { "" } else { "`where`, or " },
token_str
);
let mut err = self.struct_span_err(self.token.span, msg);
err.span_label(self.token.span, "expected `where`, or `{` after struct name");
err.span_label(
self.token.span,
format!(
"expected {}`{{` after struct name",
if parsed_where { "" } else { "`where`, or " }
),
);
return Err(err);
}