Fix `print_literal` suggests wrongly for inline literal following a numbered arg (#15583)

Closes rust-lang/rust-clippy#15576

changelog: [`numbered arg`] fix wrong suggestions for inline literal
following a numbered arg

4 files changed, 68 insertions, 10 deletions

diff --git a/clippy_lints/src/write.rs b/clippy_lints/src/write.rs
index a15e4e42e71..c55c5ec2f51 100644
--- a/clippy_lints/src/write.rs
+++ b/clippy_lints/src/write.rs
@@ -537,7 +537,7 @@ fn check_literal(cx: &LateContext<'_>, format_args: &FormatArgs, name: &str) {
 
             sug_span = Some(sug_span.unwrap_or(arg.expr.span).to(arg.expr.span));
 
-            if let Some((_, index)) = positional_arg_piece_span(piece) {
+            if let Some((_, index)) = format_arg_piece_span(piece) {
                 replaced_position.push(index);
             }
 
@@ -569,16 +569,11 @@ fn check_literal(cx: &LateContext<'_>, format_args: &FormatArgs, name: &str) {
     }
 }
 
-/// Extract Span and its index from the given `piece`, if it's positional argument.
-fn positional_arg_piece_span(piece: &FormatArgsPiece) -> Option<(Span, usize)> {
+/// Extract Span and its index from the given `piece`
+fn format_arg_piece_span(piece: &FormatArgsPiece) -> Option<(Span, usize)> {
     match piece {
         FormatArgsPiece::Placeholder(FormatPlaceholder {
-            argument:
-                FormatArgPosition {
-                    index: Ok(index),
-                    kind: FormatArgPositionKind::Number,
-                    ..
-                },
+            argument: FormatArgPosition { index: Ok(index), .. },
             span: Some(span),
             ..
         }) => Some((*span, *index)),
diff --git a/tests/ui/print_literal.fixed b/tests/ui/print_literal.fixed
index ebfe19c700e..26139f9b671 100644
--- a/tests/ui/print_literal.fixed
+++ b/tests/ui/print_literal.fixed
@@ -105,3 +105,16 @@ fn issue_14930() {
     println!("Hello x is {0:2$.1$}", 0.01, 2, 3);
     //~^ print_literal
 }
+
+fn issue_15576() {
+    println!("Hello x is {1:.*}", 5, 0.01);
+    //~^ print_literal
+
+    println!("Hello x is {:.p$}", 0.01, p = 5);
+    //~^ print_literal
+
+    println!(
+        "Hello name: x is {1:.*} (which {1} with {0} places)", 5, 0.01
+    );
+    //~^^ print_literal
+}
diff --git a/tests/ui/print_literal.rs b/tests/ui/print_literal.rs
index 8f3d9be0698..7c4cf028e84 100644
--- a/tests/ui/print_literal.rs
+++ b/tests/ui/print_literal.rs
@@ -106,3 +106,17 @@ fn issue_14930() {
     println!("Hello {0} is {1:3$.2$}", "x", 0.01, 2, 3);
     //~^ print_literal
 }
+
+fn issue_15576() {
+    println!("Hello {} is {2:.*}", "x", 5, 0.01);
+    //~^ print_literal
+
+    println!("Hello {} is {:.p$}", "x", 0.01, p = 5);
+    //~^ print_literal
+
+    println!(
+        "Hello {}: {2} is {3:.*} (which {3} with {1} places)",
+        "name", 5, "x", 0.01
+    );
+    //~^^ print_literal
+}
diff --git a/tests/ui/print_literal.stderr b/tests/ui/print_literal.stderr
index 1c378017d15..c136f52800f 100644
--- a/tests/ui/print_literal.stderr
+++ b/tests/ui/print_literal.stderr
@@ -277,5 +277,41 @@ LL -     println!("Hello {0} is {1:3$.2$}", "x", 0.01, 2, 3);
 LL +     println!("Hello x is {0:2$.1$}", 0.01, 2, 3);
    |
 
-error: aborting due to 22 previous errors
+error: literal with an empty format string
+  --> tests/ui/print_literal.rs:111:36
+   |
+LL |     println!("Hello {} is {2:.*}", "x", 5, 0.01);
+   |                                    ^^^
+   |
+help: try
+   |
+LL -     println!("Hello {} is {2:.*}", "x", 5, 0.01);
+LL +     println!("Hello x is {1:.*}", 5, 0.01);
+   |
+
+error: literal with an empty format string
+  --> tests/ui/print_literal.rs:114:36
+   |
+LL |     println!("Hello {} is {:.p$}", "x", 0.01, p = 5);
+   |                                    ^^^
+   |
+help: try
+   |
+LL -     println!("Hello {} is {:.p$}", "x", 0.01, p = 5);
+LL +     println!("Hello x is {:.p$}", 0.01, p = 5);
+   |
+
+error: literal with an empty format string
+  --> tests/ui/print_literal.rs:119:9
+   |
+LL |         "name", 5, "x", 0.01
+   |         ^^^^^^^^^^^^^^
+   |
+help: try
+   |
+LL -         "Hello {}: {2} is {3:.*} (which {3} with {1} places)",
+LL +         "Hello name: x is {1:.*} (which {1} with {0} places)", 5, 0.01
+   |
+
+error: aborting due to 25 previous errors