Add failing uninlined-format-args tests

All these tests are currently failing (generating uncompilable code).

* Implement a simplified `indoc!` proc macro
* added a `pass_through!(...)` macro test

An edge case with format arguments being wrapped in parentesis

The .fixed and .stderr were hacked without the `cargo dev bless`, so might be incorrect.

Author: nyurik

tests/ui/auxiliary/proc_macro_indoc.rs

@@ -0,0 +1,26 @@
+// compile-flags: --emit=link
+// no-prefer-dynamic
+
+#![crate_type = "proc-macro"]
+
+extern crate proc_macro;
+
+use proc_macro::{TokenStream, TokenTree};
+use std::str::FromStr;
+
+/// This code was adapted from the indoc crate
+#[proc_macro]
+pub fn simple_indoc(input: TokenStream) -> TokenStream {
+    let token = input.into_iter().next().unwrap();
+    let new_token = TokenStream::from_str(&token.to_string())
+        .unwrap()
+        .into_iter()
+        .next()
+        .unwrap();
+
+    if let TokenTree::Literal(mut lit) = new_token {
+        lit.set_span(token.span());
+        return TokenStream::from(TokenTree::Literal(lit));
+    }
+    panic!();
+}

tests/ui/uninlined_format_args.fixed

@@ -1,10 +1,18 @@
 // aux-build:proc_macro_with_span.rs
 // run-rustfix
+// aux-build:proc_macro_indoc.rs
+
 #![feature(custom_inner_attributes)]
 #![warn(clippy::uninlined_format_args)]
 #![allow(named_arguments_used_positionally, unused_imports, unused_macros, unused_variables)]
-#![allow(clippy::eq_op, clippy::format_in_format_args, clippy::print_literal)]
+#![allow(
+    clippy::double_parens,
+    clippy::eq_op,
+    clippy::format_in_format_args,
+    clippy::print_literal
+)]
 
+extern crate proc_macro_indoc;
 extern crate proc_macro_with_span;
 use proc_macro_with_span::with_span;
 
@@ -14,6 +22,12 @@ macro_rules! no_param_str {
     };
 }
 
+macro_rules! pass_through {
+    ($expr:expr) => {
+        $expr
+    };
+}
+
 macro_rules! my_println {
    ($($args:tt),*) => {{
         println!($($args),*)
@@ -123,6 +137,10 @@ fn tester(fn_arg: i32) {
     println!("{}", format!("{local_i32}"));
     my_println!("{}", local_i32);
     my_println_args!("{}", local_i32);
+    println!("{local_i32}");
+    #[rustfmt::skip]
+    println!("{local_i32}");
+    println!("{local_i32:width$.prec$}");
 
     // these should NOT be modified by the lint
     println!(concat!("nope ", "{}"), local_i32);
@@ -145,6 +163,11 @@ fn tester(fn_arg: i32) {
 
     println!(with_span!("{0} {1}" "{1} {0}"), local_i32, local_f64);
     println!("{}", with_span!(span val));
+
+    println!(pass_through!("foo={}"), local_i32);
+    println!(pass_through!("foo={a}"), a = local_i32);
+    println!(proc_macro_indoc::simple_indoc!("foo={}"), local_i32);
+    println!(proc_macro_indoc::simple_indoc!("foo={a}"), a = local_i32);
 }
 
 fn main() {

tests/ui/uninlined_format_args.rs

@@ -1,10 +1,18 @@
 // aux-build:proc_macro_with_span.rs
 // run-rustfix
+// aux-build:proc_macro_indoc.rs
+
 #![feature(custom_inner_attributes)]
 #![warn(clippy::uninlined_format_args)]
 #![allow(named_arguments_used_positionally, unused_imports, unused_macros, unused_variables)]
-#![allow(clippy::eq_op, clippy::format_in_format_args, clippy::print_literal)]
+#![allow(
+    clippy::double_parens,
+    clippy::eq_op,
+    clippy::format_in_format_args,
+    clippy::print_literal
+)]
 
+extern crate proc_macro_indoc;
 extern crate proc_macro_with_span;
 use proc_macro_with_span::with_span;
 
@@ -14,6 +22,12 @@ macro_rules! no_param_str {
     };
 }
 
+macro_rules! pass_through {
+    ($expr:expr) => {
+        $expr
+    };
+}
+
 macro_rules! my_println {
    ($($args:tt),*) => {{
         println!($($args),*)
@@ -126,6 +140,10 @@ fn tester(fn_arg: i32) {
     println!("{}", format!("{}", local_i32));
     my_println!("{}", local_i32);
     my_println_args!("{}", local_i32);
+    println!("{}", (local_i32));
+    #[rustfmt::skip]
+    println!("{}", ((local_i32)));
+    println!("{0:1$.2$}", (local_i32), (width), (prec));
 
     // these should NOT be modified by the lint
     println!(concat!("nope ", "{}"), local_i32);
@@ -150,6 +168,11 @@ fn tester(fn_arg: i32) {
 
     println!(with_span!("{0} {1}" "{1} {0}"), local_i32, local_f64);
     println!("{}", with_span!(span val));
+
+    println!(pass_through!("foo={}"), local_i32);
+    println!(pass_through!("foo={a}"), a = local_i32);
+    println!(proc_macro_indoc::simple_indoc!("foo={}"), local_i32);
+    println!(proc_macro_indoc::simple_indoc!("foo={a}"), a = local_i32);
 }
 
 fn main() {