Rollup merge of #123609 - compiler-errors:greek-question-mark, r=jieyouxu

Don't use bytepos offsets when computing semicolon span for removal

Causes problems when we recover confusable characters w/ a different byte width

Fixes #123607

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -346,7 +346,7 @@ fn check_trait_fn_not_const(&self, constness: Const, parent: &TraitOrTraitImpl<'
             in_impl: matches!(parent, TraitOrTraitImpl::TraitImpl { .. }),
             const_context_label: parent_constness,
             remove_const_sugg: (
-                self.session.source_map().span_extend_while(span, |c| c == ' ').unwrap_or(span),
+                self.session.source_map().span_extend_while_whitespace(span),
                 match parent_constness {
                     Some(_) => rustc_errors::Applicability::MachineApplicable,
                     None => rustc_errors::Applicability::MaybeIncorrect,

compiler/rustc_hir_typeck/src/expr.rs

@@ -2023,8 +2023,7 @@ fn suggest_fru_from_range_and_emit(
                 .tcx
                 .sess
                 .source_map()
-                .span_extend_while(range_start.span, |c| c.is_whitespace())
-                .unwrap_or(range_start.span)
+                .span_extend_while_whitespace(range_start.span)
                 .shrink_to_hi()
                 .to(range_end.span);
 

compiler/rustc_infer/src/infer/error_reporting/suggest.rs

@@ -15,7 +15,7 @@
 };
 use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_middle::ty::{self as ty, GenericArgKind, IsSuggestable, Ty, TypeVisitableExt};
-use rustc_span::{sym, BytePos, Span};
+use rustc_span::{sym, Span};
 
 use crate::errors::{
     ConsiderAddingAwait, FnConsiderCasting, FnItemsAreDistinct, FnUniqTypes,
@@ -763,8 +763,14 @@ pub fn could_remove_semicolon(
             let mac_call = rustc_span::source_map::original_sp(last_stmt.span, blk.span);
             self.tcx.sess.source_map().mac_call_stmt_semi_span(mac_call)?
         } else {
-            last_stmt.span.with_lo(last_stmt.span.hi() - BytePos(1))
+            self.tcx
+                .sess
+                .source_map()
+                .span_extend_while_whitespace(last_expr.span)
+                .shrink_to_hi()
+                .with_hi(last_stmt.span.hi())
         };
+
         Some((span, needs_box))
     }
 
@@ -867,10 +873,7 @@ pub fn consider_returning_binding_diag(
                         format!(" {ident} ")
                     };
                     let left_span = sm.span_through_char(blk.span, '{').shrink_to_hi();
-                    (
-                        sm.span_extend_while(left_span, |c| c.is_whitespace()).unwrap_or(left_span),
-                        sugg,
-                    )
+                    (sm.span_extend_while_whitespace(left_span), sugg)
                 };
                 Some(SuggestRemoveSemiOrReturnBinding::Add { sp: span, code: sugg, ident: *ident })
             }

compiler/rustc_lint/src/context/diagnostics.rs

@@ -215,10 +215,7 @@ pub(super) fn builtin(sess: &Session, diagnostic: BuiltinLintDiag, diag: &mut Di
             if let Some(deletion_span) = deletion_span {
                 let msg = "elide the single-use lifetime";
                 let (use_span, replace_lt) = if elide {
-                    let use_span = sess
-                        .source_map()
-                        .span_extend_while(use_span, char::is_whitespace)
-                        .unwrap_or(use_span);
+                    let use_span = sess.source_map().span_extend_while_whitespace(use_span);
                     (use_span, String::new())
                 } else {
                     (use_span, "'_".to_owned())

compiler/rustc_span/src/source_map.rs

@@ -654,6 +654,12 @@ pub fn span_extend_while(
         })
     }
 
+    /// Extends the span to include any trailing whitespace, or returns the original
+    /// span if a `SpanSnippetError` was encountered.
+    pub fn span_extend_while_whitespace(&self, span: Span) -> Span {
+        self.span_extend_while(span, char::is_whitespace).unwrap_or(span)
+    }
+
     /// Extends the given `Span` to previous character while the previous character matches the predicate
     pub fn span_extend_prev_while(
         &self,
@@ -1034,12 +1040,9 @@ pub fn stmt_span(&self, stmt_span: Span, block_span: Span) -> Span {
     /// // ^^^^^^ input
     /// ```
     pub fn mac_call_stmt_semi_span(&self, mac_call: Span) -> Option<Span> {
-        let span = self.span_extend_while(mac_call, char::is_whitespace).ok()?;
-        let span = span.shrink_to_hi().with_hi(BytePos(span.hi().0.checked_add(1)?));
-        if self.span_to_snippet(span).as_deref() != Ok(";") {
-            return None;
-        }
-        Some(span)
+        let span = self.span_extend_while_whitespace(mac_call);
+        let span = self.next_point(span);
+        if self.span_to_snippet(span).as_deref() == Ok(";") { Some(span) } else { None }
     }
 }
 

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -1592,8 +1592,7 @@ fn suggest_remove_await(&self, obligation: &PredicateObligation<'tcx>, err: &mut
                     .tcx
                     .sess
                     .source_map()
-                    .span_extend_while(expr_span, char::is_whitespace)
-                    .unwrap_or(expr_span)
+                    .span_extend_while_whitespace(expr_span)
                     .shrink_to_hi()
                     .to(await_expr.span.shrink_to_hi());
                 err.span_suggestion(
@@ -4851,10 +4850,7 @@ pub fn suggest_desugaring_async_fn_to_impl_future_in_trait<'tcx>(
     let hir::IsAsync::Async(async_span) = sig.header.asyncness else {
         return None;
     };
-    let Ok(async_span) = tcx.sess.source_map().span_extend_while(async_span, |c| c.is_whitespace())
-    else {
-        return None;
-    };
+    let async_span = tcx.sess.source_map().span_extend_while_whitespace(async_span);
 
     let future = tcx.hir_node_by_def_id(opaque_def_id).expect_item().expect_opaque_ty();
     let [hir::GenericBound::Trait(trait_ref, _)] = future.bounds else {

src/tools/clippy/clippy_lints/src/lifetimes.rs

@@ -294,8 +294,7 @@ fn elision_suggestions(
                         let span = cx
                             .sess()
                             .source_map()
-                            .span_extend_while(usage.ident.span, |ch| ch.is_ascii_whitespace())
-                            .unwrap_or(usage.ident.span);
+                            .span_extend_while_whitespace(usage.ident.span);
 
                         (span, String::new())
                     },

tests/ui/typeck/remove-semi-but-confused-char.rs

@@ -0,0 +1,11 @@
+// Ensures our "remove semicolon" suggestion isn't hardcoded with a character width,
+// in case it was accidentally mixed up with a greek question mark.
+// issue: rust-lang/rust#123607
+
+pub fn square(num: i32) -> i32 {
+    //~^ ERROR mismatched types
+    num * num;
+    //~^ ERROR unknown start of token
+}
+
+fn main() {}

tests/ui/typeck/remove-semi-but-confused-char.stderr

@@ -0,0 +1,25 @@
+error: unknown start of token: \u{37e}
+  --> $DIR/remove-semi-but-confused-char.rs:7:14
+   |
+LL |     num * num;
+   |              ^
+   |
+help: Unicode character ';' (Greek Question Mark) looks like ';' (Semicolon), but it is not
+   |
+LL |     num * num;
+   |              ~
+
+error[E0308]: mismatched types
+  --> $DIR/remove-semi-but-confused-char.rs:5:28
+   |
+LL | pub fn square(num: i32) -> i32 {
+   |        ------              ^^^ expected `i32`, found `()`
+   |        |
+   |        implicitly returns `()` as its body has no tail or `return` expression
+LL |
+LL |     num * num;
+   |              - help: remove this semicolon to return this value
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0308`.