Rollup merge of #98261 - WaffleLapkin:attempt_to_remove_max_suggestion_highlight_lines, r=flip1995

Remove `MAX_SUGGESTION_HIGHLIGHT_LINES`

After #97798 the `MAX_SUGGESTION_HIGHLIGHT_LINES` constant doesn't really make sense since we always show full suggestions. This PR removes last usages of the constant and the constant itself.

r? ``@flip1995`` (this mostly does changes in clippy)

10 files changed, 68 insertions, 186 deletions

diff --git a/compiler/rustc_errors/src/emitter.rs b/compiler/rustc_errors/src/emitter.rs
index a4cbc73978d..8b2a995f1c5 100644
--- a/compiler/rustc_errors/src/emitter.rs
+++ b/compiler/rustc_errors/src/emitter.rs
@@ -656,11 +656,6 @@ impl Emitter for SilentEmitter {
     }
 }
 
-/// Maximum number of lines we will print for a multiline suggestion; arbitrary.
-///
-/// This should be replaced with a more involved mechanism to output multiline suggestions that
-/// more closely mimics the regular diagnostic output, where irrelevant code lines are elided.
-pub const MAX_SUGGESTION_HIGHLIGHT_LINES: usize = 6;
 /// Maximum number of suggestions to be shown
 ///
 /// Arbitrary, but taken from trait import suggestion limit
diff --git a/src/tools/clippy/clippy_lints/src/methods/map_flatten.rs b/src/tools/clippy/clippy_lints/src/methods/map_flatten.rs
index f447940ea3b..8ae84dbb3dc 100644
--- a/src/tools/clippy/clippy_lints/src/methods/map_flatten.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/map_flatten.rs
@@ -1,4 +1,4 @@
-use clippy_utils::diagnostics::span_lint_and_sugg_for_edges;
+use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::is_trait_method;
 use clippy_utils::source::snippet_with_applicability;
 use clippy_utils::ty::is_type_diagnostic_item;
@@ -14,17 +14,14 @@ use super::MAP_FLATTEN;
 pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, recv: &Expr<'_>, map_arg: &Expr<'_>, map_span: Span) {
     if let Some((caller_ty_name, method_to_use)) = try_get_caller_ty_name_and_method_name(cx, expr, recv, map_arg) {
         let mut applicability = Applicability::MachineApplicable;
-        let help_msgs = [
-            &format!("try replacing `map` with `{}`", method_to_use),
-            "and remove the `.flatten()`",
-        ];
+        
         let closure_snippet = snippet_with_applicability(cx, map_arg.span, "..", &mut applicability);
-        span_lint_and_sugg_for_edges(
+        span_lint_and_sugg(
             cx,
             MAP_FLATTEN,
             expr.span.with_lo(map_span.lo()),
             &format!("called `map(..).flatten()` on `{}`", caller_ty_name),
-            &help_msgs,
+            &format!("try replacing `map` with `{}` and remove the `.flatten()`", method_to_use),
             format!("{}({})", method_to_use, closure_snippet),
             applicability,
         );
diff --git a/src/tools/clippy/clippy_lints/src/methods/or_fun_call.rs b/src/tools/clippy/clippy_lints/src/methods/or_fun_call.rs
index 448dc4e6147..3d1208824fa 100644
--- a/src/tools/clippy/clippy_lints/src/methods/or_fun_call.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/or_fun_call.rs
@@ -4,7 +4,6 @@ use clippy_utils::source::{snippet, snippet_with_applicability, snippet_with_mac
 use clippy_utils::ty::{implements_trait, match_type};
 use clippy_utils::{contains_return, is_trait_item, last_path_segment, paths};
 use if_chain::if_chain;
-use rustc_errors::emitter::MAX_SUGGESTION_HIGHLIGHT_LINES;
 use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_lint::LateContext;
@@ -33,7 +32,6 @@ pub(super) fn check<'tcx>(
         arg: &hir::Expr<'_>,
         or_has_args: bool,
         span: Span,
-        method_span: Span,
     ) -> bool {
         let is_default_default = || is_trait_item(cx, fun, sym::Default);
 
@@ -56,19 +54,14 @@ pub(super) fn check<'tcx>(
             then {
                 let mut applicability = Applicability::MachineApplicable;
                 let hint = "unwrap_or_default()";
-                let mut sugg_span = span;
+                let sugg_span = span;
 
-                let mut sugg: String = format!(
+                let sugg: String = format!(
                     "{}.{}",
                     snippet_with_applicability(cx, self_expr.span, "..", &mut applicability),
                     hint
                 );
 
-                if sugg.lines().count() > MAX_SUGGESTION_HIGHLIGHT_LINES {
-                    sugg_span = method_span.with_hi(span.hi());
-                    sugg = hint.to_string();
-                }
-
                 span_lint_and_sugg(
                     cx,
                     OR_FUN_CALL,
@@ -178,7 +171,7 @@ pub(super) fn check<'tcx>(
         match inner_arg.kind {
             hir::ExprKind::Call(fun, or_args) => {
                 let or_has_args = !or_args.is_empty();
-                if !check_unwrap_or_default(cx, name, fun, self_arg, arg, or_has_args, expr.span, method_span) {
+                if !check_unwrap_or_default(cx, name, fun, self_arg, arg, or_has_args, expr.span) {
                     let fun_span = if or_has_args { None } else { Some(fun.span) };
                     check_general_case(cx, name, method_span, self_arg, arg, expr.span, fun_span);
                 }
diff --git a/src/tools/clippy/clippy_lints/src/utils/internal_lints/metadata_collector.rs b/src/tools/clippy/clippy_lints/src/utils/internal_lints/metadata_collector.rs
index 99e9e3275ab..2564099f4db 100644
--- a/src/tools/clippy/clippy_lints/src/utils/internal_lints/metadata_collector.rs
+++ b/src/tools/clippy/clippy_lints/src/utils/internal_lints/metadata_collector.rs
@@ -112,7 +112,6 @@ const LINT_EMISSION_FUNCTIONS: [&[&str]; 8] = [
     &["clippy_utils", "diagnostics", "span_lint_and_sugg"],
     &["clippy_utils", "diagnostics", "span_lint_and_then"],
     &["clippy_utils", "diagnostics", "span_lint_hir_and_then"],
-    &["clippy_utils", "diagnostics", "span_lint_and_sugg_for_edges"],
 ];
 const SUGGESTION_DIAGNOSTIC_BUILDER_METHODS: [(&str, bool); 9] = [
     ("span_suggestion", false),
diff --git a/src/tools/clippy/clippy_utils/src/diagnostics.rs b/src/tools/clippy/clippy_utils/src/diagnostics.rs
index 39595f589c7..7f55db3b31f 100644
--- a/src/tools/clippy/clippy_utils/src/diagnostics.rs
+++ b/src/tools/clippy/clippy_utils/src/diagnostics.rs
@@ -8,7 +8,7 @@
 //! Thank you!
 //! ~The `INTERNAL_METADATA_COLLECTOR` lint
 
-use rustc_errors::{emitter::MAX_SUGGESTION_HIGHLIGHT_LINES, Applicability, Diagnostic, MultiSpan};
+use rustc_errors::{Applicability, Diagnostic, MultiSpan};
 use rustc_hir::HirId;
 use rustc_lint::{LateContext, Lint, LintContext};
 use rustc_span::source_map::Span;
@@ -219,95 +219,6 @@ pub fn span_lint_and_sugg<'a, T: LintContext>(
     });
 }
 
-/// Like [`span_lint_and_sugg`] with a focus on the edges. The output will either
-/// emit single span or multispan suggestion depending on the number of its lines.
-///
-/// If the given suggestion string has more lines than the maximum display length defined by
-/// [`MAX_SUGGESTION_HIGHLIGHT_LINES`][`rustc_errors::emitter::MAX_SUGGESTION_HIGHLIGHT_LINES`],
-/// this function will split the suggestion and span to showcase the change for the top and
-/// bottom edge of the code. For normal suggestions, in one display window, the help message
-/// will be combined with a colon.
-///
-/// Multipart suggestions like the one being created here currently cannot be
-/// applied by rustfix (See [rustfix#141](https://github.com/rust-lang/rustfix/issues/141)).
-/// Testing rustfix with this lint emission function might require a file with
-/// suggestions that can be fixed and those that can't. See
-/// [clippy#8520](https://github.com/rust-lang/rust-clippy/pull/8520/files) for
-/// an example and of this.
-///
-/// # Example for a long suggestion
-///
-/// ```text
-/// error: called `map(..).flatten()` on `Option`
-///   --> $DIR/map_flatten.rs:8:10
-///    |
-/// LL |           .map(|x| {
-///    |  __________^
-/// LL | |             if x <= 5 {
-/// LL | |                 Some(x)
-/// LL | |             } else {
-/// ...  |
-/// LL | |         })
-/// LL | |         .flatten();
-///    | |__________________^
-///    |
-///   = note: `-D clippy::map-flatten` implied by `-D warnings`
-/// help: try replacing `map` with `and_then`
-///    |
-/// LL ~         .and_then(|x| {
-/// LL +             if x <= 5 {
-/// LL +                 Some(x)
-///    |
-/// help: and remove the `.flatten()`
-///    |
-/// LL +                 None
-/// LL +             }
-/// LL ~         });
-///    |
-/// ```
-pub fn span_lint_and_sugg_for_edges(
-    cx: &LateContext<'_>,
-    lint: &'static Lint,
-    sp: Span,
-    msg: &str,
-    helps: &[&str; 2],
-    sugg: String,
-    applicability: Applicability,
-) {
-    span_lint_and_then(cx, lint, sp, msg, |diag| {
-        let sugg_lines_count = sugg.lines().count();
-        if sugg_lines_count > MAX_SUGGESTION_HIGHLIGHT_LINES {
-            let sm = cx.sess().source_map();
-            if let (Ok(line_upper), Ok(line_bottom)) =
-                (sm.lookup_line(sp.lo()), sm.lookup_line(sp.hi()))
-            {
-                let split_idx = MAX_SUGGESTION_HIGHLIGHT_LINES / 2;
-                let span_upper = sm.span_until_char(
-                    sp.with_hi(line_upper.sf.lines(|lines| lines[line_upper.line + split_idx])),
-                    '\n',
-                );
-                let span_bottom = sp.with_lo(line_bottom.sf.lines(|lines| lines[line_bottom.line - split_idx]));
-
-                let sugg_lines_vec = sugg.lines().collect::<Vec<&str>>();
-                let sugg_upper = sugg_lines_vec[..split_idx].join("\n");
-                let sugg_bottom = sugg_lines_vec[sugg_lines_count - split_idx..].join("\n");
-
-                diag.span_suggestion(span_upper, helps[0], sugg_upper, applicability);
-                diag.span_suggestion(span_bottom, helps[1], sugg_bottom, applicability);
-
-                return;
-            }
-        }
-        diag.span_suggestion_with_style(
-            sp,
-            &helps.join(", "),
-            sugg,
-            applicability,
-            rustc_errors::SuggestionStyle::ShowAlways,
-        );
-    });
-}
-
 /// Create a suggestion made from several `span → replacement`.
 ///
 /// Note: in the JSON format (used by `compiletest_rs`), the help message will
diff --git a/src/tools/clippy/tests/ui/map_flatten.stderr b/src/tools/clippy/tests/ui/map_flatten.stderr
index c9c60df838f..4b2630d6858 100644
--- a/src/tools/clippy/tests/ui/map_flatten.stderr
+++ b/src/tools/clippy/tests/ui/map_flatten.stderr
@@ -12,14 +12,12 @@ LL | |         .flatten();
    | |__________________^
    |
    = note: `-D clippy::map-flatten` implied by `-D warnings`
-help: try replacing `map` with `and_then`
+help: try replacing `map` with `and_then` and remove the `.flatten()`
    |
 LL ~         .and_then(|x| {
 LL +             if x <= 5 {
 LL +                 Some(x)
-   |
-help: and remove the `.flatten()`
-   |
+LL +             } else {
 LL +                 None
 LL +             }
 LL ~         });
@@ -38,14 +36,12 @@ LL | |         })
 LL | |         .flatten();
    | |__________________^
    |
-help: try replacing `map` with `and_then`
+help: try replacing `map` with `and_then` and remove the `.flatten()`
    |
 LL ~         .and_then(|x| {
 LL +             if x == 1 {
 LL +                 Ok(x)
-   |
-help: and remove the `.flatten()`
-   |
+LL +             } else {
 LL +                 Err(0)
 LL +             }
 LL ~         });
@@ -64,14 +60,13 @@ LL | |         })
 LL | |         .flatten();
    | |__________________^
    |
-help: try replacing `map` with `and_then`
+help: try replacing `map` with `and_then` and remove the `.flatten()`
    |
 LL ~         .and_then(|res| {
 LL +             if res > 0 {
 LL +                 do_something();
-   |
-help: and remove the `.flatten()`
-   |
+LL +                 Ok(res)
+LL +             } else {
 LL +                 Err(0)
 LL +             }
 LL ~         });
@@ -90,14 +85,12 @@ LL | |         })
 LL | |         .flatten()
    | |__________________^
    |
-help: try replacing `map` with `filter_map`
+help: try replacing `map` with `filter_map` and remove the `.flatten()`
    |
 LL ~         .filter_map(|some_value| {
 LL +             if some_value > 3 {
 LL +                 Some(some_value)
-   |
-help: and remove the `.flatten()`
-   |
+LL +             } else {
 LL +                 None
 LL +             }
 LL +         })
diff --git a/src/tools/clippy/tests/ui/map_flatten_fixable.fixed b/src/tools/clippy/tests/ui/map_flatten_fixable.fixed
index 928e5bd509c..e9b41354c58 100644
--- a/src/tools/clippy/tests/ui/map_flatten_fixable.fixed
+++ b/src/tools/clippy/tests/ui/map_flatten_fixable.fixed
@@ -59,8 +59,6 @@ fn issue8878() {
         .and_then(|_| {
 // we need some newlines
 // so that the span is big enough
-// we need some newlines
-// so that the span is big enough
 // for a splitted output of the diagnostic
             Some("")
  // whitespace beforehand is important as well
diff --git a/src/tools/clippy/tests/ui/map_flatten_fixable.stderr b/src/tools/clippy/tests/ui/map_flatten_fixable.stderr
index 828e24acaad..f3b82ad08d0 100644
--- a/src/tools/clippy/tests/ui/map_flatten_fixable.stderr
+++ b/src/tools/clippy/tests/ui/map_flatten_fixable.stderr
@@ -2,79 +2,45 @@ error: called `map(..).flatten()` on `Iterator`
   --> $DIR/map_flatten_fixable.rs:18:47
    |
 LL |     let _: Vec<_> = vec![5_i8; 6].into_iter().map(option_id).flatten().collect();
-   |                                               ^^^^^^^^^^^^^^^^^^^^^^^^
+   |                                               ^^^^^^^^^^^^^^^^^^^^^^^^ help: try replacing `map` with `filter_map` and remove the `.flatten()`: `filter_map(option_id)`
    |
    = note: `-D clippy::map-flatten` implied by `-D warnings`
-help: try replacing `map` with `filter_map`, and remove the `.flatten()`
-   |
-LL |     let _: Vec<_> = vec![5_i8; 6].into_iter().filter_map(option_id).collect();
-   |                                               ~~~~~~~~~~~~~~~~~~~~~
 
 error: called `map(..).flatten()` on `Iterator`
   --> $DIR/map_flatten_fixable.rs:19:47
    |
 LL |     let _: Vec<_> = vec![5_i8; 6].into_iter().map(option_id_ref).flatten().collect();
-   |                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: try replacing `map` with `filter_map`, and remove the `.flatten()`
-   |
-LL |     let _: Vec<_> = vec![5_i8; 6].into_iter().filter_map(option_id_ref).collect();
-   |                                               ~~~~~~~~~~~~~~~~~~~~~~~~~
+   |                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try replacing `map` with `filter_map` and remove the `.flatten()`: `filter_map(option_id_ref)`
 
 error: called `map(..).flatten()` on `Iterator`
   --> $DIR/map_flatten_fixable.rs:20:47
    |
 LL |     let _: Vec<_> = vec![5_i8; 6].into_iter().map(option_id_closure).flatten().collect();
-   |                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: try replacing `map` with `filter_map`, and remove the `.flatten()`
-   |
-LL |     let _: Vec<_> = vec![5_i8; 6].into_iter().filter_map(option_id_closure).collect();
-   |                                               ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try replacing `map` with `filter_map` and remove the `.flatten()`: `filter_map(option_id_closure)`
 
 error: called `map(..).flatten()` on `Iterator`
   --> $DIR/map_flatten_fixable.rs:21:47
    |
 LL |     let _: Vec<_> = vec![5_i8; 6].into_iter().map(|x| x.checked_add(1)).flatten().collect();
-   |                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: try replacing `map` with `filter_map`, and remove the `.flatten()`
-   |
-LL |     let _: Vec<_> = vec![5_i8; 6].into_iter().filter_map(|x| x.checked_add(1)).collect();
-   |                                               ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try replacing `map` with `filter_map` and remove the `.flatten()`: `filter_map(|x| x.checked_add(1))`
 
 error: called `map(..).flatten()` on `Iterator`
   --> $DIR/map_flatten_fixable.rs:24:47
    |
 LL |     let _: Vec<_> = vec![5_i8; 6].into_iter().map(|x| 0..x).flatten().collect();
-   |                                               ^^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: try replacing `map` with `flat_map`, and remove the `.flatten()`
-   |
-LL |     let _: Vec<_> = vec![5_i8; 6].into_iter().flat_map(|x| 0..x).collect();
-   |                                               ~~~~~~~~~~~~~~~~~~
+   |                                               ^^^^^^^^^^^^^^^^^^^^^^^ help: try replacing `map` with `flat_map` and remove the `.flatten()`: `flat_map(|x| 0..x)`
 
 error: called `map(..).flatten()` on `Option`
   --> $DIR/map_flatten_fixable.rs:27:40
    |
 LL |     let _: Option<_> = (Some(Some(1))).map(|x| x).flatten();
-   |                                        ^^^^^^^^^^^^^^^^^^^^
-   |
-help: try replacing `map` with `and_then`, and remove the `.flatten()`
-   |
-LL |     let _: Option<_> = (Some(Some(1))).and_then(|x| x);
-   |                                        ~~~~~~~~~~~~~~~
+   |                                        ^^^^^^^^^^^^^^^^^^^^ help: try replacing `map` with `and_then` and remove the `.flatten()`: `and_then(|x| x)`
 
 error: called `map(..).flatten()` on `Result`
   --> $DIR/map_flatten_fixable.rs:30:42
    |
 LL |     let _: Result<_, &str> = (Ok(Ok(1))).map(|x| x).flatten();
-   |                                          ^^^^^^^^^^^^^^^^^^^^
-   |
-help: try replacing `map` with `and_then`, and remove the `.flatten()`
-   |
-LL |     let _: Result<_, &str> = (Ok(Ok(1))).and_then(|x| x);
-   |                                          ~~~~~~~~~~~~~~~
+   |                                          ^^^^^^^^^^^^^^^^^^^^ help: try replacing `map` with `and_then` and remove the `.flatten()`: `and_then(|x| x)`
 
 error: called `map(..).flatten()` on `Option`
   --> $DIR/map_flatten_fixable.rs:59:10
@@ -89,14 +55,12 @@ LL | |         })
 LL | |         .flatten();
    | |__________________^
    |
-help: try replacing `map` with `and_then`
+help: try replacing `map` with `and_then` and remove the `.flatten()`
    |
 LL ~         .and_then(|_| {
 LL + // we need some newlines
 LL + // so that the span is big enough
-   |
-help: and remove the `.flatten()`
-   |
+LL + // for a splitted output of the diagnostic
 LL +             Some("")
 LL +  // whitespace beforehand is important as well
 LL ~         });
diff --git a/src/tools/clippy/tests/ui/or_fun_call.fixed b/src/tools/clippy/tests/ui/or_fun_call.fixed
index 3208048e0d5..123aed40251 100644
--- a/src/tools/clippy/tests/ui/or_fun_call.fixed
+++ b/src/tools/clippy/tests/ui/or_fun_call.fixed
@@ -185,8 +185,7 @@ mod issue8239 {
             .reduce(|mut acc, f| {
                 acc.push_str(&f);
                 acc
-            })
-            .unwrap_or_default();
+            }).unwrap_or_default();
     }
 
     fn more_to_max_suggestion_highest_lines_1() {
@@ -198,8 +197,7 @@ mod issue8239 {
                 let _ = "";
                 acc.push_str(&f);
                 acc
-            })
-            .unwrap_or_default();
+            }).unwrap_or_default();
     }
 
     fn equal_to_max_suggestion_highest_lines() {
diff --git a/src/tools/clippy/tests/ui/or_fun_call.stderr b/src/tools/clippy/tests/ui/or_fun_call.stderr
index 549b00ae3c4..dfe15654bc3 100644
--- a/src/tools/clippy/tests/ui/or_fun_call.stderr
+++ b/src/tools/clippy/tests/ui/or_fun_call.stderr
@@ -109,16 +109,50 @@ LL |         None.unwrap_or( unsafe { ptr_to_ref(s) }    );
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|| unsafe { ptr_to_ref(s) })`
 
 error: use of `unwrap_or` followed by a call to `new`
-  --> $DIR/or_fun_call.rs:189:14
+  --> $DIR/or_fun_call.rs:182:9
+   |
+LL | /         frames
+LL | |             .iter()
+LL | |             .map(|f: &String| f.to_lowercase())
+LL | |             .reduce(|mut acc, f| {
+...  |
+LL | |             })
+LL | |             .unwrap_or(String::new());
+   | |_____________________________________^
+   |
+help: try this
+   |
+LL ~         frames
+LL +             .iter()
+LL +             .map(|f: &String| f.to_lowercase())
+LL +             .reduce(|mut acc, f| {
+LL +                 acc.push_str(&f);
+LL +                 acc
+LL ~             }).unwrap_or_default();
    |
-LL |             .unwrap_or(String::new());
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_default()`
 
 error: use of `unwrap_or` followed by a call to `new`
-  --> $DIR/or_fun_call.rs:202:14
+  --> $DIR/or_fun_call.rs:195:9
+   |
+LL | /         iter.map(|f: &String| f.to_lowercase())
+LL | |             .reduce(|mut acc, f| {
+LL | |                 let _ = "";
+LL | |                 let _ = "";
+...  |
+LL | |             })
+LL | |             .unwrap_or(String::new());
+   | |_____________________________________^
+   |
+help: try this
+   |
+LL ~         iter.map(|f: &String| f.to_lowercase())
+LL +             .reduce(|mut acc, f| {
+LL +                 let _ = "";
+LL +                 let _ = "";
+LL +                 acc.push_str(&f);
+LL +                 acc
+LL ~             }).unwrap_or_default();
    |
-LL |             .unwrap_or(String::new());
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_default()`
 
 error: use of `unwrap_or` followed by a call to `new`
   --> $DIR/or_fun_call.rs:208:9