Make report_lit_error return ErrorGuaranteed.

This will be helpful for subsequent commits.

Author: nnethercote

Diff for: compiler/rustc_session/src/errors.rs

@@ -3,7 +3,8 @@ use std::num::NonZeroU32;
 use rustc_ast::token;
 use rustc_ast::util::literal::LitError;
 use rustc_errors::{
-    codes::*, DiagCtxt, DiagnosticBuilder, DiagnosticMessage, IntoDiagnostic, Level, MultiSpan,
+    codes::*, DiagCtxt, DiagnosticBuilder, DiagnosticMessage, ErrorGuaranteed, IntoDiagnostic,
+    Level, MultiSpan,
 };
 use rustc_macros::Diagnostic;
 use rustc_span::{Span, Symbol};
@@ -344,7 +345,12 @@ pub(crate) struct BinaryFloatLiteralNotSupported {
     pub span: Span,
 }
 
-pub fn report_lit_error(sess: &ParseSess, err: LitError, lit: token::Lit, span: Span) {
+pub fn report_lit_error(
+    sess: &ParseSess,
+    err: LitError,
+    lit: token::Lit,
+    span: Span,
+) -> ErrorGuaranteed {
     // Checks if `s` looks like i32 or u1234 etc.
     fn looks_like_width_suffix(first_chars: &[char], s: &str) -> bool {
         s.len() > 1 && s.starts_with(first_chars) && s[1..].chars().all(|c| c.is_ascii_digit())
@@ -372,44 +378,41 @@ pub fn report_lit_error(sess: &ParseSess, err: LitError, lit: token::Lit, span:
         valid.then(|| format!("0{}{}", base_char.to_ascii_lowercase(), &suffix[1..]))
     }
 
-    let token::Lit { kind, symbol, suffix, .. } = lit;
+    let token::Lit { kind, symbol, suffix } = lit;
     let dcx = &sess.dcx;
     match err {
         LitError::InvalidSuffix => {
-            if let Some(suffix) = suffix {
-                dcx.emit_err(InvalidLiteralSuffix { span, kind: kind.descr(), suffix });
-            }
+            let suffix = suffix.unwrap();
+            dcx.emit_err(InvalidLiteralSuffix { span, kind: kind.descr(), suffix })
         }
         LitError::InvalidIntSuffix => {
             let suf = suffix.expect("suffix error with no suffix");
             let suf = suf.as_str();
             if looks_like_width_suffix(&['i', 'u'], suf) {
                 // If it looks like a width, try to be helpful.
-                dcx.emit_err(InvalidIntLiteralWidth { span, width: suf[1..].into() });
+                dcx.emit_err(InvalidIntLiteralWidth { span, width: suf[1..].into() })
             } else if let Some(fixed) = fix_base_capitalisation(symbol.as_str(), suf) {
-                dcx.emit_err(InvalidNumLiteralBasePrefix { span, fixed });
+                dcx.emit_err(InvalidNumLiteralBasePrefix { span, fixed })
             } else {
-                dcx.emit_err(InvalidNumLiteralSuffix { span, suffix: suf.to_string() });
+                dcx.emit_err(InvalidNumLiteralSuffix { span, suffix: suf.to_string() })
             }
         }
         LitError::InvalidFloatSuffix => {
             let suf = suffix.expect("suffix error with no suffix");
             let suf = suf.as_str();
             if looks_like_width_suffix(&['f'], suf) {
                 // If it looks like a width, try to be helpful.
-                dcx.emit_err(InvalidFloatLiteralWidth { span, width: suf[1..].to_string() });
+                dcx.emit_err(InvalidFloatLiteralWidth { span, width: suf[1..].to_string() })
             } else {
-                dcx.emit_err(InvalidFloatLiteralSuffix { span, suffix: suf.to_string() });
+                dcx.emit_err(InvalidFloatLiteralSuffix { span, suffix: suf.to_string() })
             }
         }
-        LitError::NonDecimalFloat(base) => {
-            match base {
-                16 => dcx.emit_err(HexadecimalFloatLiteralNotSupported { span }),
-                8 => dcx.emit_err(OctalFloatLiteralNotSupported { span }),
-                2 => dcx.emit_err(BinaryFloatLiteralNotSupported { span }),
-                _ => unreachable!(),
-            };
-        }
+        LitError::NonDecimalFloat(base) => match base {
+            16 => dcx.emit_err(HexadecimalFloatLiteralNotSupported { span }),
+            8 => dcx.emit_err(OctalFloatLiteralNotSupported { span }),
+            2 => dcx.emit_err(BinaryFloatLiteralNotSupported { span }),
+            _ => unreachable!(),
+        },
         LitError::IntTooLarge(base) => {
             let max = u128::MAX;
             let limit = match base {
@@ -418,7 +421,7 @@ pub fn report_lit_error(sess: &ParseSess, err: LitError, lit: token::Lit, span:
                 16 => format!("{max:#x}"),
                 _ => format!("{max}"),
             };
-            dcx.emit_err(IntLiteralTooLarge { span, limit });
+            dcx.emit_err(IntLiteralTooLarge { span, limit })
         }
     }
 }