diff --git a/compiler/rustc_errors/src/diagnostic.rs b/compiler/rustc_errors/src/diagnostic.rs
index 518c59dba5366..a63fc0ca285da 100644
--- a/compiler/rustc_errors/src/diagnostic.rs
+++ b/compiler/rustc_errors/src/diagnostic.rs
@@ -567,6 +567,11 @@ impl Diagnostic {
         style: SuggestionStyle,
     ) -> &mut Self {
         assert!(!suggestion.is_empty());
+        debug_assert!(
+            !(suggestion.iter().any(|(sp, text)| sp.is_empty() && text.is_empty())),
+            "Span must not be empty and have no suggestion"
+        );
+
         self.push_suggestion(CodeSuggestion {
             substitutions: vec![Substitution {
                 parts: suggestion
@@ -644,6 +649,10 @@ impl Diagnostic {
         applicability: Applicability,
         style: SuggestionStyle,
     ) -> &mut Self {
+        debug_assert!(
+            !(sp.is_empty() && suggestion.to_string().is_empty()),
+            "Span must not be empty and have no suggestion"
+        );
         self.push_suggestion(CodeSuggestion {
             substitutions: vec![Substitution {
                 parts: vec![SubstitutionPart { snippet: suggestion.to_string(), span: sp }],
@@ -684,6 +693,12 @@ impl Diagnostic {
     ) -> &mut Self {
         let mut suggestions: Vec<_> = suggestions.collect();
         suggestions.sort();
+
+        debug_assert!(
+            !(sp.is_empty() && suggestions.iter().any(|suggestion| suggestion.is_empty())),
+            "Span must not be empty and have no suggestion"
+        );
+
         let substitutions = suggestions
             .into_iter()
             .map(|snippet| Substitution { parts: vec![SubstitutionPart { snippet, span: sp }] })
@@ -705,8 +720,18 @@ impl Diagnostic {
         suggestions: impl Iterator<Item = Vec<(Span, String)>>,
         applicability: Applicability,
     ) -> &mut Self {
+        let suggestions: Vec<_> = suggestions.collect();
+        debug_assert!(
+            !(suggestions
+                .iter()
+                .flat_map(|suggs| suggs)
+                .any(|(sp, suggestion)| sp.is_empty() && suggestion.is_empty())),
+            "Span must not be empty and have no suggestion"
+        );
+
         self.push_suggestion(CodeSuggestion {
             substitutions: suggestions
+                .into_iter()
                 .map(|sugg| Substitution {
                     parts: sugg
                         .into_iter()
diff --git a/compiler/rustc_expand/src/base.rs b/compiler/rustc_expand/src/base.rs
index cd8a525e062c5..052ca229f0127 100644
--- a/compiler/rustc_expand/src/base.rs
+++ b/compiler/rustc_expand/src/base.rs
@@ -22,7 +22,7 @@ use rustc_span::edition::Edition;
 use rustc_span::hygiene::{AstPass, ExpnData, ExpnKind, LocalExpnId};
 use rustc_span::source_map::SourceMap;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
-use rustc_span::{FileName, Span, DUMMY_SP};
+use rustc_span::{BytePos, FileName, Span, DUMMY_SP};
 use smallvec::{smallvec, SmallVec};
 
 use std::default::Default;
@@ -1228,8 +1228,9 @@ pub fn expr_to_spanned_string<'a>(
             ast::LitKind::Str(s, style) => return Ok((s, style, expr.span)),
             ast::LitKind::ByteStr(_) => {
                 let mut err = cx.struct_span_err(l.span, err_msg);
+                let span = expr.span.shrink_to_lo();
                 err.span_suggestion(
-                    expr.span.shrink_to_lo(),
+                    span.with_hi(span.lo() + BytePos(1)),
                     "consider removing the leading `b`",
                     "",
                     Applicability::MaybeIncorrect,
diff --git a/compiler/rustc_hir_analysis/src/astconv/mod.rs b/compiler/rustc_hir_analysis/src/astconv/mod.rs
index 6e373e41b4c02..a8f70ba2b3780 100644
--- a/compiler/rustc_hir_analysis/src/astconv/mod.rs
+++ b/compiler/rustc_hir_analysis/src/astconv/mod.rs
@@ -3051,24 +3051,27 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                     .map_or(false, |s| s.trim_end().ends_with('<'));
 
             let is_global = poly_trait_ref.trait_ref.path.is_global();
-            let sugg = Vec::from_iter([
-                (
-                    self_ty.span.shrink_to_lo(),
-                    format!(
-                        "{}dyn {}",
-                        if needs_bracket { "<" } else { "" },
-                        if is_global { "(" } else { "" },
-                    ),
+
+            let mut sugg = Vec::from_iter([(
+                self_ty.span.shrink_to_lo(),
+                format!(
+                    "{}dyn {}",
+                    if needs_bracket { "<" } else { "" },
+                    if is_global { "(" } else { "" },
                 ),
-                (
+            )]);
+
+            if is_global || needs_bracket {
+                sugg.push((
                     self_ty.span.shrink_to_hi(),
                     format!(
                         "{}{}",
                         if is_global { ")" } else { "" },
                         if needs_bracket { ">" } else { "" },
                     ),
-                ),
-            ]);
+                ));
+            }
+
             if self_ty.span.edition() >= Edition::Edition2021 {
                 let msg = "trait objects must include the `dyn` keyword";
                 let label = "add `dyn` keyword before this trait";
diff --git a/compiler/rustc_parse/src/parser/diagnostics.rs b/compiler/rustc_parse/src/parser/diagnostics.rs
index 40d85c833a7dd..d654d84cdd594 100644
--- a/compiler/rustc_parse/src/parser/diagnostics.rs
+++ b/compiler/rustc_parse/src/parser/diagnostics.rs
@@ -1374,9 +1374,17 @@ impl<'a> Parser<'a> {
         kind: IncDecRecovery,
         (pre_span, post_span): (Span, Span),
     ) -> MultiSugg {
+        let mut patches = Vec::new();
+
+        if !pre_span.is_empty() {
+            patches.push((pre_span, String::new()));
+        }
+
+        patches.push((post_span, format!(" {}= 1", kind.op.chr())));
+
         MultiSugg {
             msg: format!("use `{}= 1` instead", kind.op.chr()),
-            patches: vec![(pre_span, String::new()), (post_span, format!(" {}= 1", kind.op.chr()))],
+            patches,
             applicability: Applicability::MachineApplicable,
         }
     }
diff --git a/src/tools/clippy/clippy_lints/src/manual_assert.rs b/src/tools/clippy/clippy_lints/src/manual_assert.rs
index 825ec84b4a812..b8ed9b9ec18f7 100644
--- a/src/tools/clippy/clippy_lints/src/manual_assert.rs
+++ b/src/tools/clippy/clippy_lints/src/manual_assert.rs
@@ -69,11 +69,13 @@ impl<'tcx> LateLintPass<'tcx> for ManualAssert {
                     "only a `panic!` in `if`-then statement",
                     |diag| {
                         // comments can be noisy, do not show them to the user
-                        diag.tool_only_span_suggestion(
-                                    expr.span.shrink_to_lo(),
-                                    "add comments back",
-                                    comments,
-                                    applicability);
+                        if !comments.is_empty() {
+                            diag.tool_only_span_suggestion(
+                                        expr.span.shrink_to_lo(),
+                                        "add comments back",
+                                        comments,
+                                        applicability);
+                        }
                         diag.span_suggestion(
                                     expr.span,
                                     "try instead",
diff --git a/src/tools/clippy/clippy_lints/src/needless_late_init.rs b/src/tools/clippy/clippy_lints/src/needless_late_init.rs
index 9d26e5900866c..67debe7e08af6 100644
--- a/src/tools/clippy/clippy_lints/src/needless_late_init.rs
+++ b/src/tools/clippy/clippy_lints/src/needless_late_init.rs
@@ -180,10 +180,13 @@ fn assignment_suggestions<'tcx>(
     let suggestions = assignments
         .iter()
         .flat_map(|assignment| {
-            [
-                assignment.span.until(assignment.rhs_span),
-                assignment.rhs_span.shrink_to_hi().with_hi(assignment.span.hi()),
-            ]
+            let mut spans = vec![assignment.span.until(assignment.rhs_span)];
+
+            if assignment.rhs_span.hi() != assignment.span.hi() {
+                spans.push(assignment.rhs_span.shrink_to_hi().with_hi(assignment.span.hi()));
+            }
+
+            spans
         })
         .map(|span| (span, String::new()))
         .collect::<Vec<(Span, String)>>();
diff --git a/src/tools/clippy/tests/ui/manual_assert.edition2018.stderr b/src/tools/clippy/tests/ui/manual_assert.edition2018.stderr
index 7718588fdf6f4..237638ee1344c 100644
--- a/src/tools/clippy/tests/ui/manual_assert.edition2018.stderr
+++ b/src/tools/clippy/tests/ui/manual_assert.edition2018.stderr
@@ -4,13 +4,9 @@ error: only a `panic!` in `if`-then statement
 LL | /     if !a.is_empty() {
 LL | |         panic!("qaqaq{:?}", a);
 LL | |     }
-   | |_____^
+   | |_____^ help: try instead: `assert!(a.is_empty(), "qaqaq{:?}", a);`
    |
    = note: `-D clippy::manual-assert` implied by `-D warnings`
-help: try instead
-   |
-LL |     assert!(a.is_empty(), "qaqaq{:?}", a);
-   |
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:34:5
@@ -18,12 +14,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if !a.is_empty() {
 LL | |         panic!("qwqwq");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(a.is_empty(), "qwqwq");
-   |
+   | |_____^ help: try instead: `assert!(a.is_empty(), "qwqwq");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:51:5
@@ -31,12 +22,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if b.is_empty() {
 LL | |         panic!("panic1");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!b.is_empty(), "panic1");
-   |
+   | |_____^ help: try instead: `assert!(!b.is_empty(), "panic1");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:54:5
@@ -44,12 +30,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if b.is_empty() && a.is_empty() {
 LL | |         panic!("panic2");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!(b.is_empty() && a.is_empty()), "panic2");
-   |
+   | |_____^ help: try instead: `assert!(!(b.is_empty() && a.is_empty()), "panic2");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:57:5
@@ -57,12 +38,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if a.is_empty() && !b.is_empty() {
 LL | |         panic!("panic3");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!(a.is_empty() && !b.is_empty()), "panic3");
-   |
+   | |_____^ help: try instead: `assert!(!(a.is_empty() && !b.is_empty()), "panic3");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:60:5
@@ -70,12 +46,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if b.is_empty() || a.is_empty() {
 LL | |         panic!("panic4");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!(b.is_empty() || a.is_empty()), "panic4");
-   |
+   | |_____^ help: try instead: `assert!(!(b.is_empty() || a.is_empty()), "panic4");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:63:5
@@ -83,12 +54,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if a.is_empty() || !b.is_empty() {
 LL | |         panic!("panic5");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!(a.is_empty() || !b.is_empty()), "panic5");
-   |
+   | |_____^ help: try instead: `assert!(!(a.is_empty() || !b.is_empty()), "panic5");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:66:5
@@ -96,12 +62,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if a.is_empty() {
 LL | |         panic!("with expansion {}", one!())
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!a.is_empty(), "with expansion {}", one!());
-   |
+   | |_____^ help: try instead: `assert!(!a.is_empty(), "with expansion {}", one!());`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:73:5
diff --git a/src/tools/clippy/tests/ui/manual_assert.edition2021.stderr b/src/tools/clippy/tests/ui/manual_assert.edition2021.stderr
index 7718588fdf6f4..237638ee1344c 100644
--- a/src/tools/clippy/tests/ui/manual_assert.edition2021.stderr
+++ b/src/tools/clippy/tests/ui/manual_assert.edition2021.stderr
@@ -4,13 +4,9 @@ error: only a `panic!` in `if`-then statement
 LL | /     if !a.is_empty() {
 LL | |         panic!("qaqaq{:?}", a);
 LL | |     }
-   | |_____^
+   | |_____^ help: try instead: `assert!(a.is_empty(), "qaqaq{:?}", a);`
    |
    = note: `-D clippy::manual-assert` implied by `-D warnings`
-help: try instead
-   |
-LL |     assert!(a.is_empty(), "qaqaq{:?}", a);
-   |
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:34:5
@@ -18,12 +14,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if !a.is_empty() {
 LL | |         panic!("qwqwq");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(a.is_empty(), "qwqwq");
-   |
+   | |_____^ help: try instead: `assert!(a.is_empty(), "qwqwq");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:51:5
@@ -31,12 +22,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if b.is_empty() {
 LL | |         panic!("panic1");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!b.is_empty(), "panic1");
-   |
+   | |_____^ help: try instead: `assert!(!b.is_empty(), "panic1");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:54:5
@@ -44,12 +30,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if b.is_empty() && a.is_empty() {
 LL | |         panic!("panic2");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!(b.is_empty() && a.is_empty()), "panic2");
-   |
+   | |_____^ help: try instead: `assert!(!(b.is_empty() && a.is_empty()), "panic2");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:57:5
@@ -57,12 +38,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if a.is_empty() && !b.is_empty() {
 LL | |         panic!("panic3");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!(a.is_empty() && !b.is_empty()), "panic3");
-   |
+   | |_____^ help: try instead: `assert!(!(a.is_empty() && !b.is_empty()), "panic3");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:60:5
@@ -70,12 +46,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if b.is_empty() || a.is_empty() {
 LL | |         panic!("panic4");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!(b.is_empty() || a.is_empty()), "panic4");
-   |
+   | |_____^ help: try instead: `assert!(!(b.is_empty() || a.is_empty()), "panic4");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:63:5
@@ -83,12 +54,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if a.is_empty() || !b.is_empty() {
 LL | |         panic!("panic5");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!(a.is_empty() || !b.is_empty()), "panic5");
-   |
+   | |_____^ help: try instead: `assert!(!(a.is_empty() || !b.is_empty()), "panic5");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:66:5
@@ -96,12 +62,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if a.is_empty() {
 LL | |         panic!("with expansion {}", one!())
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!a.is_empty(), "with expansion {}", one!());
-   |
+   | |_____^ help: try instead: `assert!(!a.is_empty(), "with expansion {}", one!());`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:73:5