Use {:?} spans in use_debug

Author: Alexendoo

clippy_lints/src/write.rs

@@ -1,5 +1,5 @@
 use clippy_utils::diagnostics::{span_lint, span_lint_and_then};
-use clippy_utils::macros::{root_macro_call_first_node, FormatArgsExpn, MacroCall};
+use clippy_utils::macros::{root_macro_call_first_node, FormatArgsArg, FormatArgsExpn, MacroCall};
 use clippy_utils::source::snippet_opt;
 use rustc_ast::LitKind;
 use rustc_errors::Applicability;
@@ -275,6 +275,9 @@ impl<'tcx> LateLintPass<'tcx> for Write {
         }
 
         let Some(format_args) = FormatArgsExpn::find_nested(cx, expr, macro_call.expn) else { return };
+        if format_args.format_string_span.from_expansion() {
+            return;
+        }
 
         match diag_name {
             sym::print_macro | sym::eprint_macro | sym::write_macro => {
@@ -286,20 +289,11 @@ impl<'tcx> LateLintPass<'tcx> for Write {
             _ => {},
         }
 
-        check_literal(cx, &format_args, name);
+        let Some(args) = format_args.args(cx) else { return };
+        check_literal(cx, &args, name, format_args.is_raw(cx));
 
-        if !self.in_debug_impl
-            && format_args
-                .formatters
-                .iter()
-                .any(|&(_, formatter)| formatter == sym::Debug)
-        {
-            span_lint(
-                cx,
-                USE_DEBUG,
-                format_args.format_string_span,
-                "use of `Debug`-based formatting",
-            );
+        if !self.in_debug_impl {
+            check_use_debug(cx, &args);
         }
     }
 }
@@ -335,7 +329,6 @@ fn check_newline(cx: &LateContext<'_>, format_args: &FormatArgsExpn<'_>, macro_c
     };
 
     if_chain! {
-        if !format_string_span.from_expansion();
         if last.as_str().ends_with('\n');
 
         // ignore format strings with other internal vertical whitespace
@@ -401,9 +394,6 @@ fn check_empty_string(cx: &LateContext<'_>, format_args: &FormatArgsExpn<'_>, ma
         let mut span = format_args.format_string_span;
 
         if part.as_str() == "\n";
-        // `println!()` is also represented with an "\n" format string part, but
-        // its span is from an expansion
-        if !span.from_expansion();
         then {
             let lint = if name == "writeln" {
                 span = expand_past_previous_comma(cx, span);
@@ -432,15 +422,9 @@ fn check_empty_string(cx: &LateContext<'_>, format_args: &FormatArgsExpn<'_>, ma
     }
 }
 
-fn check_literal<'tcx>(cx: &LateContext<'tcx>, format_args: &FormatArgsExpn<'tcx>, name: &str) {
-    if format_args.format_string_span.from_expansion() {
-        return;
-    }
-    let raw = format_args.is_raw(cx);
-
-    let Some(args) = format_args.args(cx) else { return };
+fn check_literal(cx: &LateContext<'_>, args: &[FormatArgsArg<'_>], name: &str, raw: bool) {
     let mut counts = HirIdMap::<usize>::default();
-    for arg in &args {
+    for arg in args {
         *counts.entry(arg.value.hir_id).or_default() += 1;
     }
 
@@ -505,3 +489,16 @@ fn expand_past_previous_comma(cx: &LateContext<'_>, span: Span) -> Span {
     let extended = cx.sess().source_map().span_extend_to_prev_char(span, ',', true);
     extended.with_lo(extended.lo() - BytePos(1))
 }
+
+fn check_use_debug(cx: &LateContext<'_>, args: &[FormatArgsArg<'_>]) {
+    for arg in args {
+        if arg.format_trait == sym::Debug {
+            span_lint(
+                cx,
+                USE_DEBUG,
+                arg.span,
+                "use of `Debug`-based formatting",
+            );
+        }
+    }
+}

tests/ui/print.stderr

@@ -1,8 +1,8 @@
 error: use of `Debug`-based formatting
-  --> $DIR/print.rs:11:19
+  --> $DIR/print.rs:11:20
    |
 LL |         write!(f, "{:?}", 43.1415)
-   |                   ^^^^^^
+   |                    ^^^^
    |
    = note: `-D clippy::use-debug` implied by `-D warnings`
 
@@ -33,10 +33,10 @@ LL |     print!("Hello {:?}", "World");
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: use of `Debug`-based formatting
-  --> $DIR/print.rs:28:12
+  --> $DIR/print.rs:28:19
    |
 LL |     print!("Hello {:?}", "World");
-   |            ^^^^^^^^^^^^
+   |                   ^^^^
 
 error: use of `print!`
   --> $DIR/print.rs:30:5
@@ -45,10 +45,10 @@ LL |     print!("Hello {:#?}", "#orld");
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: use of `Debug`-based formatting
-  --> $DIR/print.rs:30:12
+  --> $DIR/print.rs:30:19
    |
 LL |     print!("Hello {:#?}", "#orld");
-   |            ^^^^^^^^^^^^^
+   |                   ^^^^^
 
 error: aborting due to 8 previous errors