Remove LitError::LexerError.

`cook_lexer_literal` can emit an error about an invalid int literal but
then return a non-`Err` token. And then `integer_lit` has to account for
this to avoid printing a redundant error message.

This commit changes `cook_lexer_literal` to return `Err` in that case.
Then `integer_lit` doesn't need the special case, and
`LitError::LexerError` can be removed.

Author: nnethercote

compiler/rustc_ast/src/util/literal.rs

@@ -31,7 +31,6 @@ pub fn escape_byte_str_symbol(bytes: &[u8]) -> Symbol {
 
 #[derive(Debug)]
 pub enum LitError {
-    LexerError,
     InvalidSuffix,
     InvalidIntSuffix,
     InvalidFloatSuffix,
@@ -324,11 +323,7 @@ fn integer_lit(symbol: Symbol, suffix: Option<Symbol>) -> Result<LitKind, LitErr
     };
 
     let s = &s[if base != 10 { 2 } else { 0 }..];
-    u128::from_str_radix(s, base).map(|i| LitKind::Int(i.into(), ty)).map_err(|_| {
-        // Small bases are lexed as if they were base 10, e.g, the string
-        // might be `0b10201`. This will cause the conversion above to fail,
-        // but these kinds of errors are already reported by the lexer.
-        let from_lexer = base < 10 && s.chars().any(|c| c.to_digit(10).is_some_and(|d| d >= base));
-        if from_lexer { LitError::LexerError } else { LitError::IntTooLarge(base) }
-    })
+    u128::from_str_radix(s, base)
+        .map(|i| LitKind::Int(i.into(), ty))
+        .map_err(|_| LitError::IntTooLarge(base))
 }

compiler/rustc_parse/src/lexer/mod.rs

@@ -16,7 +16,7 @@ use rustc_session::lint::builtin::{
 };
 use rustc_session::lint::BuiltinLintDiagnostics;
 use rustc_session::parse::ParseSess;
-use rustc_span::symbol::{sym, Symbol};
+use rustc_span::symbol::Symbol;
 use rustc_span::{edition::Edition, BytePos, Pos, Span};
 
 mod diagnostics;
@@ -478,26 +478,26 @@ impl<'sess, 'src> StringReader<'sess, 'src> {
                 }
             }
             rustc_lexer::LiteralKind::Int { base, empty_int } => {
+                let mut kind = token::Integer;
                 if empty_int {
                     let span = self.mk_sp(start, end);
                     self.dcx().emit_err(errors::NoDigitsLiteral { span });
-                    (token::Integer, sym::integer(0))
-                } else {
-                    if matches!(base, Base::Binary | Base::Octal) {
-                        let base = base as u32;
-                        let s = self.str_from_to(start + BytePos(2), end);
-                        for (idx, c) in s.char_indices() {
-                            let span = self.mk_sp(
-                                start + BytePos::from_usize(2 + idx),
-                                start + BytePos::from_usize(2 + idx + c.len_utf8()),
-                            );
-                            if c != '_' && c.to_digit(base).is_none() {
-                                self.dcx().emit_err(errors::InvalidDigitLiteral { span, base });
-                            }
+                    kind = token::Err;
+                } else if matches!(base, Base::Binary | Base::Octal) {
+                    let base = base as u32;
+                    let s = self.str_from_to(start + BytePos(2), end);
+                    for (idx, c) in s.char_indices() {
+                        let span = self.mk_sp(
+                            start + BytePos::from_usize(2 + idx),
+                            start + BytePos::from_usize(2 + idx + c.len_utf8()),
+                        );
+                        if c != '_' && c.to_digit(base).is_none() {
+                            self.dcx().emit_err(errors::InvalidDigitLiteral { span, base });
+                            kind = token::Err;
                         }
                     }
-                    (token::Integer, self.symbol_from_to(start, end))
                 }
+                (kind, self.symbol_from_to(start, end))
             }
             rustc_lexer::LiteralKind::Float { base, empty_exponent } => {
                 if empty_exponent {

compiler/rustc_session/src/errors.rs

@@ -375,9 +375,6 @@ pub fn report_lit_error(sess: &ParseSess, err: LitError, lit: token::Lit, span:
     let token::Lit { kind, symbol, suffix, .. } = lit;
     let dcx = &sess.dcx;
     match err {
-        // `LexerError` is an error, but it was already reported
-        // by lexer, so here we don't report it the second time.
-        LitError::LexerError => {}
         LitError::InvalidSuffix => {
             if let Some(suffix) = suffix {
                 dcx.emit_err(InvalidLiteralSuffix { span, kind: kind.descr(), suffix });