Emits suggestions for expressions with parentheses or not separately

compiler/rustc_lint/messages.ftl

@@ -197,7 +197,9 @@ lint_drop_glue =
     types that do not implement `Drop` can still have drop glue, consider instead using `{$needs_drop}` to detect whether a type is trivially dropped
 
 lint_range_endpoint_out_of_range = range endpoint is out of range for `{$ty}`
-    .suggestion = use an inclusive range instead
+
+lint_range_use_inclusive_range = use an inclusive range instead
+
 
 lint_overflowing_bin_hex = literal out of range for `{$ty}`
     .negative_note = the literal `{$lit}` (decimal `{$dec}`) does not fit into the type `{$ty}`

compiler/rustc_lint/src/lints.rs

@@ -1210,12 +1210,33 @@ impl<'a> DecorateLint<'a, ()> for DropGlue<'_> {
 #[diag(lint_range_endpoint_out_of_range)]
 pub struct RangeEndpointOutOfRange<'a> {
     pub ty: &'a str,
-    #[suggestion(code = "=", applicability = "machine-applicable")]
-    pub eq_suggestion: Span,
-    #[suggestion(code = "{literal}{suffix}", applicability = "machine-applicable")]
-    pub lit_suggestion: Span,
-    pub literal: u128,
-    pub suffix: &'a str,
+    #[subdiagnostic]
+    pub sub: UseInclusiveRange<'a>,
+}
+
+#[derive(Subdiagnostic)]
+pub enum UseInclusiveRange<'a> {
+    #[suggestion(
+        lint_range_use_inclusive_range,
+        code = "{start}..={literal}{suffix}",
+        applicability = "machine-applicable"
+    )]
+    WithoutParen {
+        #[primary_span]
+        sugg: Span,
+        start: String,
+        literal: u128,
+        suffix: &'a str,
+    },
+    #[multipart_suggestion(lint_range_use_inclusive_range, applicability = "machine-applicable")]
+    WithParen {
+        #[suggestion_part(code = "=")]
+        eq_sugg: Span,
+        #[suggestion_part(code = "{literal}{suffix}")]
+        lit_sugg: Span,
+        literal: u128,
+        suffix: &'a str,
+    },
 }
 
 #[derive(LintDiagnostic)]

compiler/rustc_lint/src/types.rs

@@ -4,7 +4,8 @@ use crate::{
         AtomicOrderingFence, AtomicOrderingLoad, AtomicOrderingStore, ImproperCTypes,
         InvalidAtomicOrderingDiag, OnlyCastu8ToChar, OverflowingBinHex, OverflowingBinHexSign,
         OverflowingBinHexSub, OverflowingInt, OverflowingIntHelp, OverflowingLiteral,
-        OverflowingUInt, RangeEndpointOutOfRange, UnusedComparisons, VariantSizeDifferencesDiag,
+        OverflowingUInt, RangeEndpointOutOfRange, UnusedComparisons, UseInclusiveRange,
+        VariantSizeDifferencesDiag,
     },
 };
 use crate::{LateContext, LateLintPass, LintContext};
@@ -172,16 +173,27 @@ fn lint_overflowing_range_endpoint<'tcx>(
         _ => bug!(),
     };
 
+    let sub_sugg = if expr.span.lo() == lit_span.lo() {
+        let Ok(start) = cx.sess().source_map().span_to_snippet(eps[0].span) else { return false };
+        UseInclusiveRange::WithoutParen {
+            sugg: struct_expr.span.shrink_to_lo().to(lit_span.shrink_to_hi()),
+            start,
+            literal: lit_val - 1,
+            suffix,
+        }
+    } else {
+        UseInclusiveRange::WithParen {
+            eq_sugg: expr.span.shrink_to_lo(),
+            lit_sugg: lit_span,
+            literal: lit_val - 1,
+            suffix,
+        }
+    };
+
     cx.emit_spanned_lint(
         OVERFLOWING_LITERALS,
         struct_expr.span,
-        RangeEndpointOutOfRange {
-            ty,
-            eq_suggestion: expr.span.shrink_to_lo(),
-            lit_suggestion: lit_span,
-            literal: lit_val - 1,
-            suffix,
-        },
+        RangeEndpointOutOfRange { ty, sub: sub_sugg },
     );
 
     // We've just emitted a lint, special cased for `(...)..MAX+1` ranges,

tests/ui/lint/issue-109529.rs

@@ -1,5 +1,4 @@
 fn main() {
-    for i in 0..(256 as u8) { //~ ERROR range endpoint is out of range
-        println!("{}", i);
-    }
+    for _ in 0..256 as u8 {} //~ ERROR range endpoint is out of range
+    for _ in 0..(256 as u8) {} //~ ERROR range endpoint is out of range
 }

tests/ui/lint/issue-109529.stderr

@@ -1,18 +1,23 @@
 error: range endpoint is out of range for `u8`
   --> $DIR/issue-109529.rs:2:14
    |
-LL |     for i in 0..(256 as u8) {
-   |              ^^^^^^^^^^^^^^
+LL |     for _ in 0..256 as u8 {}
+   |              ------^^^^^^
+   |              |
+   |              help: use an inclusive range instead: `0..=255`
    |
    = note: `#[deny(overflowing_literals)]` on by default
-help: use an inclusive range instead
+
+error: range endpoint is out of range for `u8`
+  --> $DIR/issue-109529.rs:3:14
+   |
+LL |     for _ in 0..(256 as u8) {}
+   |              ^^^^^^^^^^^^^^
    |
-LL |     for i in 0..=(256 as u8) {
-   |                 +
 help: use an inclusive range instead
    |
-LL |     for i in 0..(255 as u8) {
-   |                  ~~~
+LL |     for _ in 0..=(255 as u8) {}
+   |                 + ~~~
 
-error: aborting due to previous error
+error: aborting due to 2 previous errors