Rollup merge of #100058 - TaKO8Ki:suggest-positional-formatting-argument-instead-of-format-args-capture, r=estebank

Suggest a positional formatting argument instead of a captured argument

This patch fixes a part of #96999.

fixes #98241
fixes #97311

r? `@estebank`

3 files changed, 115 insertions, 0 deletions

diff --git a/src/test/ui/fmt/struct-field-as-captured-argument.fixed b/src/test/ui/fmt/struct-field-as-captured-argument.fixed
new file mode 100644
index 00000000000..f7244f6744f
--- /dev/null
+++ b/src/test/ui/fmt/struct-field-as-captured-argument.fixed
@@ -0,0 +1,18 @@
+// run-rustfix
+
+#[derive(Debug)]
+struct Foo {
+    field: usize,
+}
+
+fn main() {
+    let foo = Foo { field: 0 };
+    let bar = 3;
+    format!("{0}", foo.field); //~ ERROR invalid format string: field access isn't supported
+    format!("{1} {} {bar}", "aa", foo.field); //~ ERROR invalid format string: field access isn't supported
+    format!("{2} {} {1} {bar}", "aa", "bb", foo.field); //~ ERROR invalid format string: field access isn't supported
+    format!("{1} {} {baz}", "aa", foo.field, baz = 3); //~ ERROR invalid format string: field access isn't supported
+    format!("{1:?} {} {baz}", "aa", foo.field, baz = 3); //~ ERROR invalid format string: field access isn't supported
+    format!("{1:#?} {} {baz}", "aa", foo.field, baz = 3); //~ ERROR invalid format string: field access isn't supported
+    format!("{1:.3} {} {baz}", "aa", foo.field, baz = 3); //~ ERROR invalid format string: field access isn't supported
+}
diff --git a/src/test/ui/fmt/struct-field-as-captured-argument.rs b/src/test/ui/fmt/struct-field-as-captured-argument.rs
new file mode 100644
index 00000000000..ab5f2552bd3
--- /dev/null
+++ b/src/test/ui/fmt/struct-field-as-captured-argument.rs
@@ -0,0 +1,18 @@
+// run-rustfix
+
+#[derive(Debug)]
+struct Foo {
+    field: usize,
+}
+
+fn main() {
+    let foo = Foo { field: 0 };
+    let bar = 3;
+    format!("{foo.field}"); //~ ERROR invalid format string: field access isn't supported
+    format!("{foo.field} {} {bar}", "aa"); //~ ERROR invalid format string: field access isn't supported
+    format!("{foo.field} {} {1} {bar}", "aa", "bb"); //~ ERROR invalid format string: field access isn't supported
+    format!("{foo.field} {} {baz}", "aa", baz = 3); //~ ERROR invalid format string: field access isn't supported
+    format!("{foo.field:?} {} {baz}", "aa", baz = 3); //~ ERROR invalid format string: field access isn't supported
+    format!("{foo.field:#?} {} {baz}", "aa", baz = 3); //~ ERROR invalid format string: field access isn't supported
+    format!("{foo.field:.3} {} {baz}", "aa", baz = 3); //~ ERROR invalid format string: field access isn't supported
+}
diff --git a/src/test/ui/fmt/struct-field-as-captured-argument.stderr b/src/test/ui/fmt/struct-field-as-captured-argument.stderr
new file mode 100644
index 00000000000..7ea8b4068f2
--- /dev/null
+++ b/src/test/ui/fmt/struct-field-as-captured-argument.stderr
@@ -0,0 +1,79 @@
+error: invalid format string: field access isn't supported
+  --> $DIR/struct-field-as-captured-argument.rs:11:15
+   |
+LL |     format!("{foo.field}");
+   |               ^^^^^^^^^ not supported in format string
+   |
+help: consider using a positional formatting argument instead
+   |
+LL |     format!("{0}", foo.field);
+   |               ~  +++++++++++
+
+error: invalid format string: field access isn't supported
+  --> $DIR/struct-field-as-captured-argument.rs:12:15
+   |
+LL |     format!("{foo.field} {} {bar}", "aa");
+   |               ^^^^^^^^^ not supported in format string
+   |
+help: consider using a positional formatting argument instead
+   |
+LL |     format!("{1} {} {bar}", "aa", foo.field);
+   |               ~                 +++++++++++
+
+error: invalid format string: field access isn't supported
+  --> $DIR/struct-field-as-captured-argument.rs:13:15
+   |
+LL |     format!("{foo.field} {} {1} {bar}", "aa", "bb");
+   |               ^^^^^^^^^ not supported in format string
+   |
+help: consider using a positional formatting argument instead
+   |
+LL |     format!("{2} {} {1} {bar}", "aa", "bb", foo.field);
+   |               ~                           +++++++++++
+
+error: invalid format string: field access isn't supported
+  --> $DIR/struct-field-as-captured-argument.rs:14:15
+   |
+LL |     format!("{foo.field} {} {baz}", "aa", baz = 3);
+   |               ^^^^^^^^^ not supported in format string
+   |
+help: consider using a positional formatting argument instead
+   |
+LL |     format!("{1} {} {baz}", "aa", foo.field, baz = 3);
+   |               ~                 +++++++++++
+
+error: invalid format string: field access isn't supported
+  --> $DIR/struct-field-as-captured-argument.rs:15:15
+   |
+LL |     format!("{foo.field:?} {} {baz}", "aa", baz = 3);
+   |               ^^^^^^^^^ not supported in format string
+   |
+help: consider using a positional formatting argument instead
+   |
+LL |     format!("{1:?} {} {baz}", "aa", foo.field, baz = 3);
+   |               ~                   +++++++++++
+
+error: invalid format string: field access isn't supported
+  --> $DIR/struct-field-as-captured-argument.rs:16:15
+   |
+LL |     format!("{foo.field:#?} {} {baz}", "aa", baz = 3);
+   |               ^^^^^^^^^ not supported in format string
+   |
+help: consider using a positional formatting argument instead
+   |
+LL |     format!("{1:#?} {} {baz}", "aa", foo.field, baz = 3);
+   |               ~                    +++++++++++
+
+error: invalid format string: field access isn't supported
+  --> $DIR/struct-field-as-captured-argument.rs:17:15
+   |
+LL |     format!("{foo.field:.3} {} {baz}", "aa", baz = 3);
+   |               ^^^^^^^^^ not supported in format string
+   |
+help: consider using a positional formatting argument instead
+   |
+LL |     format!("{1:.3} {} {baz}", "aa", foo.field, baz = 3);
+   |               ~                    +++++++++++
+
+error: aborting due to 7 previous errors
+