Auto merge of #5141 - xiongmao86:issue5095, r=flip1995

Fixes issue 5095

fixes #5095.

- [x] Followed [lint naming conventions][lint_naming]
- [x] Added passing UI tests (including committed `.stderr` file)
- [x] `cargo test` passes locally
- [x] Executed `cargo dev update_lints`
- [x] Added lint documentation
- [x] Run `cargo dev fmt`

[lint_naming]: https://rust-lang.github.io/rfcs/0344-conventions-galore.html#lints

changelog: (internal) warn about collapsible `span_lint_and_then` calls.

Author: bors

clippy_lints/src/as_conversions.rs

@@ -50,6 +50,7 @@ impl EarlyLintPass for AsConversions {
                 AS_CONVERSIONS,
                 expr.span,
                 "using a potentially dangerous silent `as` conversion",
+                None,
                 "consider using a safe wrapper for this conversion",
             );
         }

clippy_lints/src/assertions_on_constants.rs

@@ -41,6 +41,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for AssertionsOnConstants {
                 } else {
                     "`assert!(true)` will be optimized out by the compiler"
                 },
+                None,
                 "remove it",
             );
         };
@@ -50,6 +51,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for AssertionsOnConstants {
                 ASSERTIONS_ON_CONSTANTS,
                 e.span,
                 "`assert!(false)` should probably be replaced",
+                None,
                 "use `panic!()` or `unreachable!()`",
             );
         };
@@ -59,6 +61,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for AssertionsOnConstants {
                 ASSERTIONS_ON_CONSTANTS,
                 e.span,
                 &format!("`assert!(false, {})` should probably be replaced", panic_message),
+                None,
                 &format!("use `panic!({})` or `unreachable!({})`", panic_message, panic_message),
             )
         };

clippy_lints/src/atomic_ordering.rs

@@ -85,6 +85,7 @@ fn check_atomic_load_store(cx: &LateContext<'_, '_>, expr: &Expr<'_>) {
                     INVALID_ATOMIC_ORDERING,
                     ordering_arg.span,
                     "atomic loads cannot have `Release` and `AcqRel` ordering",
+                    None,
                     "consider using ordering modes `Acquire`, `SeqCst` or `Relaxed`"
                 );
             } else if method == "store" &&
@@ -94,6 +95,7 @@ fn check_atomic_load_store(cx: &LateContext<'_, '_>, expr: &Expr<'_>) {
                     INVALID_ATOMIC_ORDERING,
                     ordering_arg.span,
                     "atomic stores cannot have `Acquire` and `AcqRel` ordering",
+                    None,
                     "consider using ordering modes `Release`, `SeqCst` or `Relaxed`"
                 );
             }
@@ -118,6 +120,7 @@ fn check_memory_fence(cx: &LateContext<'_, '_>, expr: &Expr<'_>) {
                 INVALID_ATOMIC_ORDERING,
                 args[0].span,
                 "memory fences cannot have `Relaxed` ordering",
+                None,
                 "consider using ordering modes `Acquire`, `Release`, `AcqRel` or `SeqCst`"
             );
         }

clippy_lints/src/cognitive_complexity.rs

@@ -105,6 +105,7 @@ impl CognitiveComplexity {
                     rust_cc,
                     self.limit.limit()
                 ),
+                None,
                 "you could split it up into multiple smaller functions",
             );
         }

clippy_lints/src/comparison_chain.rs

@@ -104,6 +104,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ComparisonChain {
             COMPARISON_CHAIN,
             expr.span,
             "`if` chain can be rewritten with `match`",
+            None,
             "Consider rewriting the `if` chain to use `cmp` and `match`.",
         )
     }

clippy_lints/src/copies.rs

@@ -183,7 +183,7 @@ fn lint_same_then_else(cx: &LateContext<'_, '_>, blocks: &[&Block<'_>]) {
             IF_SAME_THEN_ELSE,
             j.span,
             "this `if` has identical blocks",
-            i.span,
+            Some(i.span),
             "same as this",
         );
     }
@@ -206,7 +206,7 @@ fn lint_same_cond(cx: &LateContext<'_, '_>, conds: &[&Expr<'_>]) {
             IFS_SAME_COND,
             j.span,
             "this `if` has the same condition as a previous `if`",
-            i.span,
+            Some(i.span),
             "same as this",
         );
     }
@@ -234,7 +234,7 @@ fn lint_same_fns_in_if_cond(cx: &LateContext<'_, '_>, conds: &[&Expr<'_>]) {
             SAME_FUNCTIONS_IN_IF_CONDITION,
             j.span,
             "this `if` has the same function call as a previous `if`",
-            i.span,
+            Some(i.span),
             "same as this",
         );
     }

clippy_lints/src/copy_iterator.rs

@@ -46,7 +46,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for CopyIterator {
                     COPY_ITERATOR,
                     item.span,
                     "you are implementing `Iterator` on a `Copy` type",
-                    item.span,
+                    None,
                     "consider implementing `IntoIterator` instead",
                 );
             }

clippy_lints/src/dbg_macro.rs

@@ -48,6 +48,7 @@ impl EarlyLintPass for DbgMacro {
                     DBG_MACRO,
                     mac.span(),
                     "`dbg!` macro is intended as a debugging tool",
+                    None,
                     "ensure to avoid having uses of it in version control",
                 );
             }

clippy_lints/src/derive.rs

@@ -1,5 +1,5 @@
 use crate::utils::paths;
-use crate::utils::{is_automatically_derived, is_copy, match_path, span_lint_and_then};
+use crate::utils::{is_automatically_derived, is_copy, match_path, span_lint_and_note, span_lint_and_then};
 use if_chain::if_chain;
 use rustc_hir::{Item, ItemKind, TraitRef};
 use rustc_lint::{LateContext, LateLintPass};
@@ -163,14 +163,13 @@ fn check_copy_clone<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, item: &Item<'_>, trait
             _ => (),
         }
 
-        span_lint_and_then(
+        span_lint_and_note(
             cx,
             EXPL_IMPL_CLONE_ON_COPY,
             item.span,
             "you are implementing `Clone` explicitly on a `Copy` type",
-            |diag| {
-                diag.span_note(item.span, "consider deriving `Clone` or removing `Copy`");
-            },
+            Some(item.span),
+            "consider deriving `Clone` or removing `Copy`",
         );
     }
 }

clippy_lints/src/drop_forget_ref.rs

@@ -135,7 +135,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for DropForgetRef {
                                        lint,
                                        expr.span,
                                        &msg,
-                                       arg.span,
+                                       Some(arg.span),
                                        &format!("argument has type `{}`", arg_ty));
                 } else if is_copy(cx, arg_ty) {
                     if match_def_path(cx, def_id, &paths::DROP) {
@@ -151,7 +151,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for DropForgetRef {
                                        lint,
                                        expr.span,
                                        &msg,
-                                       arg.span,
+                                       Some(arg.span),
                                        &format!("argument has type {}", arg_ty));
                 }
             }