too_many_lines: only highlight the function signature

Author: ada4a

clippy_lints/src/functions/mod.rs

@@ -503,7 +503,7 @@ impl<'tcx> LateLintPass<'tcx> for Functions {
     ) {
         let hir_id = cx.tcx.local_def_id_to_hir_id(def_id);
         too_many_arguments::check_fn(cx, kind, decl, span, hir_id, self.too_many_arguments_threshold);
-        too_many_lines::check_fn(cx, kind, body, span, self.too_many_lines_threshold);
+        too_many_lines::check_fn(cx, kind, body, span, hir_id, self.too_many_lines_threshold);
         not_unsafe_ptr_arg_deref::check_fn(cx, kind, decl, body, def_id);
         misnamed_getters::check_fn(cx, kind, decl, body, span);
         impl_trait_in_params::check_fn(cx, &kind, body, hir_id);

clippy_lints/src/functions/too_many_lines.rs

@@ -1,7 +1,7 @@
 use clippy_utils::diagnostics::span_lint;
 use clippy_utils::source::SpanRangeExt;
-use rustc_hir as hir;
 use rustc_hir::intravisit::FnKind;
+use rustc_hir::{self as hir, HirId};
 use rustc_lint::{LateContext, LintContext};
 use rustc_span::Span;
 
@@ -12,6 +12,7 @@ pub(super) fn check_fn(
     kind: FnKind<'_>,
     body: &hir::Body<'_>,
     span: Span,
+    hir_id: HirId,
     too_many_lines_threshold: u64,
 ) {
     // Closures must be contained in a parent body, which will be checked for `too_many_lines`.
@@ -70,11 +71,21 @@ pub(super) fn check_fn(
         line_count > too_many_lines_threshold
     });
 
+    let fn_sig = match kind {
+        FnKind::ItemFn(..) => cx
+            .tcx
+            .hir_node(hir_id)
+            .fn_sig()
+            .expect("`hir_id` is that of a function"),
+        FnKind::Method(_, fn_sig) => fn_sig,
+        FnKind::Closure => unreachable!("early-returned by the guard clause"),
+    };
+
     if too_many {
         span_lint(
             cx,
             TOO_MANY_LINES,
-            span,
+            fn_sig.span,
             format!("this function has too many lines ({line_count}/{too_many_lines_threshold})"),
         );
     }

tests/ui-toml/functions_maxlines/test.stderr

@@ -1,48 +1,29 @@
 error: this function has too many lines (2/1)
   --> tests/ui-toml/functions_maxlines/test.rs:19:1
    |
-LL | / fn too_many_lines() {
-LL | |
-LL | |     println!("This is bad.");
-LL | |     println!("This is bad.");
-LL | | }
-   | |_^
+LL | fn too_many_lines() {
+   | ^^^^^^^^^^^^^^^^^^^
    |
    = note: `-D clippy::too-many-lines` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(clippy::too_many_lines)]`
 
 error: this function has too many lines (4/1)
   --> tests/ui-toml/functions_maxlines/test.rs:26:1
    |
-LL | / async fn async_too_many_lines() {
-LL | |
-LL | |     println!("This is bad.");
-LL | |     println!("This is bad.");
-LL | | }
-   | |_^
+LL | async fn async_too_many_lines() {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: this function has too many lines (4/1)
   --> tests/ui-toml/functions_maxlines/test.rs:33:1
    |
-LL | / fn closure_too_many_lines() {
-LL | |
-LL | |     let _ = {
-LL | |         println!("This is bad.");
-LL | |         println!("This is bad.");
-LL | |     };
-LL | | }
-   | |_^
+LL | fn closure_too_many_lines() {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: this function has too many lines (2/1)
   --> tests/ui-toml/functions_maxlines/test.rs:56:1
    |
-LL | / fn comment_before_code() {
-LL | |
-LL | |     let _ = "test";
-LL | |     /* This comment extends to the front of
-LL | |     the code but this line should still count. */ let _ = 5;
-LL | | }
-   | |_^
+LL | fn comment_before_code() {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 4 previous errors
 

tests/ui/functions_maxlines.stderr

@@ -1,17 +1,17 @@
-error: this function has too many lines (102/100)
-  --> tests/ui/functions_maxlines.rs:58:1
+error: this function has too many lines (104/100)
+  --> tests/ui/functions_maxlines.rs:60:1
    |
-LL | / fn bad_lines() {
-LL | |
-LL | |
-LL | |     println!("Dont get confused by braces: {{}}");
-...  |
-LL | |     println!("This is bad.");
-LL | | }
-   | |_^
+LL | pub async unsafe extern "Rust" fn bad_lines() -> () {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: `-D clippy::too-many-lines` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(clippy::too_many_lines)]`
 
-error: aborting due to 1 previous error
+error: this function has too many lines (104/100)
+  --> tests/ui/functions_maxlines.rs:170:5
+   |
+LL |     pub async unsafe extern "Rust" fn bad_lines() -> () {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors