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Rollup merge of #108854 - Ezrashaw:improve-int-idents, r=oli-obk
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feat/refactor: improve errors in case of ident with number at start

Improve parser code when we parse a integer (or float) literal but expect an identifier. We emit an error message saying that identifiers can't begin with numbers. This PR just improves that code and expands it to all identifiers. Note that I haven't implemented error recovery (this didn't exist before anyway), I might do that in a follow up PR.
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matthiaskrgr authored Mar 9, 2023
2 parents aedd94f + 252e0b3 commit bec7011
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Showing 9 changed files with 68 additions and 45 deletions.
3 changes: 1 addition & 2 deletions compiler/rustc_parse/locales/en-US.ftl
Original file line number Diff line number Diff line change
Expand Up @@ -412,8 +412,7 @@ parse_fn_ptr_with_generics = function pointer types may not have generic paramet
*[false] a
} `for` parameter list
parse_invalid_identifier_with_leading_number = expected identifier, found number literal
.label = identifiers cannot start with a number
parse_invalid_identifier_with_leading_number = identifiers cannot start with a number
parse_maybe_fn_typo_with_impl = you might have meant to write `impl` instead of `fn`
.suggestion = replace `fn` with `impl` here
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17 changes: 9 additions & 8 deletions compiler/rustc_parse/src/errors.rs
Original file line number Diff line number Diff line change
Expand Up @@ -939,6 +939,7 @@ pub(crate) struct ExpectedIdentifier {
pub token: Token,
pub suggest_raw: Option<SuggEscapeToUseAsIdentifier>,
pub suggest_remove_comma: Option<SuggRemoveComma>,
pub help_cannot_start_number: Option<HelpIdentifierStartsWithNumber>,
}

impl<'a, G: EmissionGuarantee> IntoDiagnostic<'a, G> for ExpectedIdentifier {
Expand Down Expand Up @@ -975,10 +976,18 @@ impl<'a, G: EmissionGuarantee> IntoDiagnostic<'a, G> for ExpectedIdentifier {
sugg.add_to_diagnostic(&mut diag);
}

if let Some(help) = self.help_cannot_start_number {
help.add_to_diagnostic(&mut diag);
}

diag
}
}

#[derive(Subdiagnostic)]
#[help(parse_invalid_identifier_with_leading_number)]
pub(crate) struct HelpIdentifierStartsWithNumber;

pub(crate) struct ExpectedSemi {
pub span: Span,
pub token: Token,
Expand Down Expand Up @@ -1207,14 +1216,6 @@ pub(crate) struct SelfParamNotFirst {
pub span: Span,
}

#[derive(Diagnostic)]
#[diag(parse_invalid_identifier_with_leading_number)]
pub(crate) struct InvalidIdentiferStartsWithNumber {
#[primary_span]
#[label]
pub span: Span,
}

#[derive(Diagnostic)]
#[diag(parse_const_generic_without_braces)]
pub(crate) struct ConstGenericWithoutBraces {
Expand Down
41 changes: 27 additions & 14 deletions compiler/rustc_parse/src/parser/diagnostics.rs
Original file line number Diff line number Diff line change
Expand Up @@ -8,14 +8,14 @@ use crate::errors::{
ComparisonOperatorsCannotBeChained, ComparisonOperatorsCannotBeChainedSugg,
ConstGenericWithoutBraces, ConstGenericWithoutBracesSugg, DocCommentOnParamType,
DoubleColonInBound, ExpectedIdentifier, ExpectedSemi, ExpectedSemiSugg,
GenericParamsWithoutAngleBrackets, GenericParamsWithoutAngleBracketsSugg, InInTypo,
IncorrectAwait, IncorrectSemicolon, IncorrectUseOfAwait, ParenthesesInForHead,
ParenthesesInForHeadSugg, PatternMethodParamWithoutBody, QuestionMarkInType,
QuestionMarkInTypeSugg, SelfParamNotFirst, StructLiteralBodyWithoutPath,
StructLiteralBodyWithoutPathSugg, StructLiteralNeedingParens, StructLiteralNeedingParensSugg,
SuggEscapeToUseAsIdentifier, SuggRemoveComma, UnexpectedConstInGenericParam,
UnexpectedConstParamDeclaration, UnexpectedConstParamDeclarationSugg, UnmatchedAngleBrackets,
UseEqInstead,
GenericParamsWithoutAngleBrackets, GenericParamsWithoutAngleBracketsSugg,
HelpIdentifierStartsWithNumber, InInTypo, IncorrectAwait, IncorrectSemicolon,
IncorrectUseOfAwait, ParenthesesInForHead, ParenthesesInForHeadSugg,
PatternMethodParamWithoutBody, QuestionMarkInType, QuestionMarkInTypeSugg, SelfParamNotFirst,
StructLiteralBodyWithoutPath, StructLiteralBodyWithoutPathSugg, StructLiteralNeedingParens,
StructLiteralNeedingParensSugg, SuggEscapeToUseAsIdentifier, SuggRemoveComma,
UnexpectedConstInGenericParam, UnexpectedConstParamDeclaration,
UnexpectedConstParamDeclarationSugg, UnmatchedAngleBrackets, UseEqInstead,
};

use crate::fluent_generated as fluent;
Expand Down Expand Up @@ -280,6 +280,7 @@ impl<'a> Parser<'a> {
TokenKind::CloseDelim(Delimiter::Brace),
TokenKind::CloseDelim(Delimiter::Parenthesis),
];

let suggest_raw = match self.token.ident() {
Some((ident, false))
if ident.is_raw_guess()
Expand All @@ -295,18 +296,19 @@ impl<'a> Parser<'a> {
_ => None,
};

let suggest_remove_comma =
if self.token == token::Comma && self.look_ahead(1, |t| t.is_ident()) {
Some(SuggRemoveComma { span: self.token.span })
} else {
None
};
let suggest_remove_comma = (self.token == token::Comma
&& self.look_ahead(1, |t| t.is_ident()))
.then_some(SuggRemoveComma { span: self.token.span });

let help_cannot_start_number =
self.is_lit_bad_ident().then_some(HelpIdentifierStartsWithNumber);

let err = ExpectedIdentifier {
span: self.token.span,
token: self.token.clone(),
suggest_raw,
suggest_remove_comma,
help_cannot_start_number,
};
let mut err = err.into_diagnostic(&self.sess.span_diagnostic);

Expand Down Expand Up @@ -365,6 +367,17 @@ impl<'a> Parser<'a> {
err
}

/// Checks if the current token is a integer or float literal and looks like
/// it could be a invalid identifier with digits at the start.
pub(super) fn is_lit_bad_ident(&mut self) -> bool {
matches!(self.token.uninterpolate().kind, token::Literal(Lit { kind: token::LitKind::Integer | token::LitKind::Float, .. })
// ensure that the integer literal is followed by a *invalid*
// suffix: this is how we know that it is a identifier with an
// invalid beginning.
if rustc_ast::MetaItemLit::from_token(&self.token).is_none()
)
}

pub(super) fn expected_one_of_not_found(
&mut self,
edible: &[TokenKind],
Expand Down
4 changes: 4 additions & 0 deletions compiler/rustc_parse/src/parser/pat.rs
Original file line number Diff line number Diff line change
Expand Up @@ -348,6 +348,10 @@ impl<'a> Parser<'a> {
lo = self.token.span;
}

if self.is_lit_bad_ident() {
return Err(self.expected_ident_found());
}

let pat = if self.check(&token::BinOp(token::And)) || self.token.kind == token::AndAnd {
self.parse_pat_deref(expected)?
} else if self.check(&token::OpenDelim(Delimiter::Parenthesis)) {
Expand Down
12 changes: 0 additions & 12 deletions compiler/rustc_parse/src/parser/stmt.rs
Original file line number Diff line number Diff line change
Expand Up @@ -273,7 +273,6 @@ impl<'a> Parser<'a> {
self.bump();
}

self.report_invalid_identifier_error()?;
let (pat, colon) =
self.parse_pat_before_ty(None, RecoverComma::Yes, PatternLocation::LetBinding)?;

Expand Down Expand Up @@ -366,17 +365,6 @@ impl<'a> Parser<'a> {
Ok(P(ast::Local { ty, pat, kind, id: DUMMY_NODE_ID, span: lo.to(hi), attrs, tokens: None }))
}

/// report error for `let 1x = 123`
pub fn report_invalid_identifier_error(&mut self) -> PResult<'a, ()> {
if let token::Literal(lit) = self.token.uninterpolate().kind &&
rustc_ast::MetaItemLit::from_token(&self.token).is_none() &&
(lit.kind == token::LitKind::Integer || lit.kind == token::LitKind::Float) &&
self.look_ahead(1, |t| matches!(t.kind, token::Eq) || matches!(t.kind, token::Colon ) ) {
return Err(self.sess.create_err(errors::InvalidIdentiferStartsWithNumber { span: self.token.span }));
}
Ok(())
}

fn check_let_else_init_bool_expr(&self, init: &ast::Expr) {
if let ast::ExprKind::Binary(op, ..) = init.kind {
if op.node.lazy() {
Expand Down
2 changes: 2 additions & 0 deletions tests/ui/parser/integer-literal-start-ident.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
fn 1main() {}
//~^ ERROR expected identifier, found `1main`
10 changes: 10 additions & 0 deletions tests/ui/parser/integer-literal-start-ident.stderr
Original file line number Diff line number Diff line change
@@ -0,0 +1,10 @@
error: expected identifier, found `1main`
--> $DIR/integer-literal-start-ident.rs:1:4
|
LL | fn 1main() {}
| ^^^^^ expected identifier
|
= help: identifiers cannot start with a number

error: aborting due to previous error

6 changes: 3 additions & 3 deletions tests/ui/parser/issues/issue-104088.rs
Original file line number Diff line number Diff line change
Expand Up @@ -4,12 +4,12 @@ fn test() {

fn test_2() {
let 1x = 123;
//~^ ERROR expected identifier, found number literal
//~^ ERROR expected identifier, found `1x`
}

fn test_3() {
let 2x: i32 = 123;
//~^ ERROR expected identifier, found number literal
//~^ ERROR expected identifier, found `2x`
}

fn test_4() {
Expand All @@ -20,7 +20,7 @@ fn test_4() {

fn test_5() {
let 23name = 123;
//~^ ERROR expected identifier, found number literal
//~^ ERROR expected identifier, found `23name`
}

fn main() {}
18 changes: 12 additions & 6 deletions tests/ui/parser/issues/issue-104088.stderr
Original file line number Diff line number Diff line change
@@ -1,20 +1,26 @@
error: expected identifier, found number literal
error: expected identifier, found `1x`
--> $DIR/issue-104088.rs:6:9
|
LL | let 1x = 123;
| ^^ identifiers cannot start with a number
| ^^ expected identifier
|
= help: identifiers cannot start with a number

error: expected identifier, found number literal
error: expected identifier, found `2x`
--> $DIR/issue-104088.rs:11:9
|
LL | let 2x: i32 = 123;
| ^^ identifiers cannot start with a number
| ^^ expected identifier
|
= help: identifiers cannot start with a number

error: expected identifier, found number literal
error: expected identifier, found `23name`
--> $DIR/issue-104088.rs:22:9
|
LL | let 23name = 123;
| ^^^^^^ identifiers cannot start with a number
| ^^^^^^ expected identifier
|
= help: identifiers cannot start with a number

error[E0308]: mismatched types
--> $DIR/issue-104088.rs:16:12
Expand Down

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