[Experiment] Remove format_args_nl!()

compiler/rustc_builtin_macros/src/asm.rs

@@ -534,7 +534,6 @@ fn expand_preparsed_asm(ecx: &mut ExtCtxt<'_>, args: AsmArgs) -> Option<ast::Inl
             template_str,
             str_style,
             template_snippet,
-            false,
             parse::ParseMode::InlineAsm,
         );
         parser.curarg = curarg;

compiler/rustc_builtin_macros/src/format.rs

@@ -153,21 +153,13 @@ fn parse_args<'a>(ecx: &mut ExtCtxt<'a>, sp: Span, tts: TokenStream) -> PResult<
     Ok(MacroInput { fmtstr, args, is_direct_literal })
 }
 
-fn make_format_args(
-    ecx: &mut ExtCtxt<'_>,
-    input: MacroInput,
-    append_newline: bool,
-) -> Result<FormatArgs, ()> {
+fn make_format_args(ecx: &mut ExtCtxt<'_>, input: MacroInput) -> Result<FormatArgs, ()> {
     let msg = "format argument must be a string literal";
     let unexpanded_fmt_span = input.fmtstr.span;
 
     let MacroInput { fmtstr: efmt, mut args, is_direct_literal } = input;
 
     let (fmt_str, fmt_style, fmt_span) = match expr_to_spanned_string(ecx, efmt, msg) {
-        Ok(mut fmt) if append_newline => {
-            fmt.0 = Symbol::intern(&format!("{}\n", fmt.0));
-            fmt
-        }
         Ok(fmt) => fmt,
         Err(err) => {
             if let Some((mut err, suggested)) = err {
@@ -196,13 +188,7 @@ fn make_format_args(
 
     let fmt_str = fmt_str.as_str(); // for the suggestions below
     let fmt_snippet = ecx.source_map().span_to_snippet(unexpanded_fmt_span).ok();
-    let mut parser = parse::Parser::new(
-        fmt_str,
-        str_style,
-        fmt_snippet,
-        append_newline,
-        parse::ParseMode::Format,
-    );
+    let mut parser = parse::Parser::new(fmt_str, str_style, fmt_snippet, parse::ParseMode::Format);
 
     let mut pieces = Vec::new();
     while let Some(piece) = parser.next() {
@@ -831,16 +817,15 @@ fn report_invalid_references(
     e.emit();
 }
 
-fn expand_format_args_impl<'cx>(
+pub fn expand_format_args<'cx>(
     ecx: &'cx mut ExtCtxt<'_>,
     mut sp: Span,
     tts: TokenStream,
-    nl: bool,
 ) -> Box<dyn base::MacResult + 'cx> {
     sp = ecx.with_def_site_ctxt(sp);
     match parse_args(ecx, sp, tts) {
         Ok(input) => {
-            if let Ok(format_args) = make_format_args(ecx, input, nl) {
+            if let Ok(format_args) = make_format_args(ecx, input) {
                 MacEager::expr(ecx.expr(sp, ExprKind::FormatArgs(P(format_args))))
             } else {
                 MacEager::expr(DummyResult::raw_expr(sp, true))
@@ -852,19 +837,3 @@ fn expand_format_args_impl<'cx>(
         }
     }
 }
-
-pub fn expand_format_args<'cx>(
-    ecx: &'cx mut ExtCtxt<'_>,
-    sp: Span,
-    tts: TokenStream,
-) -> Box<dyn base::MacResult + 'cx> {
-    expand_format_args_impl(ecx, sp, tts, false)
-}
-
-pub fn expand_format_args_nl<'cx>(
-    ecx: &'cx mut ExtCtxt<'_>,
-    sp: Span,
-    tts: TokenStream,
-) -> Box<dyn base::MacResult + 'cx> {
-    expand_format_args_impl(ecx, sp, tts, true)
-}

compiler/rustc_builtin_macros/src/lib.rs

@@ -83,7 +83,6 @@ pub fn register_builtin_macros(resolver: &mut dyn ResolverExpand) {
         concat: concat::expand_concat,
         env: env::expand_env,
         file: source_util::expand_file,
-        format_args_nl: format::expand_format_args_nl,
         format_args: format::expand_format_args,
         const_format_args: format::expand_format_args,
         global_asm: asm::expand_global_asm,

compiler/rustc_lint/src/non_fmt_panic.rs

@@ -244,7 +244,7 @@ fn check_panic_str<'tcx>(
         Err(_) => (None, None),
     };
 
-    let mut fmt_parser = Parser::new(fmt, style, snippet.clone(), false, ParseMode::Format);
+    let mut fmt_parser = Parser::new(fmt, style, snippet.clone(), ParseMode::Format);
     let n_arguments = (&mut fmt_parser).filter(|a| matches!(a, Piece::NextArgument(_))).count();
 
     if n_arguments > 0 && fmt_parser.errors.is_empty() {

compiler/rustc_parse_format/src/lib.rs

@@ -233,8 +233,6 @@ pub struct Parser<'a> {
     width_map: Vec<InnerWidthMapping>,
     /// Span of the last opening brace seen, used for error reporting
     last_opening_brace: Option<InnerSpan>,
-    /// Whether the source string is comes from `println!` as opposed to `format!` or `print!`
-    append_newline: bool,
     /// Whether this formatting string was written directly in the source. This controls whether we
     /// can use spans to refer into it and give better error messages.
     /// N.B: This does _not_ control whether implicit argument captures can be used.
@@ -322,7 +320,6 @@ impl<'a> Parser<'a> {
         s: &'a str,
         style: Option<usize>,
         snippet: Option<string::String>,
-        append_newline: bool,
         mode: ParseMode,
     ) -> Parser<'a> {
         let input_string_kind = find_width_map_from_snippet(s, snippet, style);
@@ -341,7 +338,6 @@ impl<'a> Parser<'a> {
             arg_places: vec![],
             width_map,
             last_opening_brace: None,
-            append_newline,
             is_source_literal,
             cur_line_start: 0,
             line_spans: vec![],
@@ -485,8 +481,7 @@ impl<'a> Parser<'a> {
         } else {
             let description = format!("expected `{c:?}` but string was terminated");
             // point at closing `"`
-            let pos = self.input.len() - if self.append_newline { 1 } else { 0 };
-            let pos = self.to_span_index(pos);
+            let pos = self.to_span_index(self.input.len());
             if c == '}' {
                 let label = format!("expected `{c:?}`");
                 let (note, secondary_label) = if c == '}' {

compiler/rustc_parse_format/src/tests.rs

@@ -2,7 +2,7 @@ use super::*;
 
 #[track_caller]
 fn same(fmt: &'static str, p: &[Piece<'static>]) {
-    let parser = Parser::new(fmt, None, None, false, ParseMode::Format);
+    let parser = Parser::new(fmt, None, None, ParseMode::Format);
     assert_eq!(parser.collect::<Vec<Piece<'static>>>(), p);
 }
 
@@ -24,7 +24,7 @@ fn fmtdflt() -> FormatSpec<'static> {
 }
 
 fn musterr(s: &str) {
-    let mut p = Parser::new(s, None, None, false, ParseMode::Format);
+    let mut p = Parser::new(s, None, None, ParseMode::Format);
     p.next();
     assert!(!p.errors.is_empty());
 }

compiler/rustc_span/src/symbol.rs

@@ -734,7 +734,6 @@ symbols! {
         format_args,
         format_args_capture,
         format_args_macro,
-        format_args_nl,
         format_argument,
         format_arguments,
         format_count,

compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs

@@ -576,7 +576,7 @@ impl<'tcx> OnUnimplementedFormatString {
         let trait_name = tcx.item_name(trait_def_id);
         let generics = tcx.generics_of(item_def_id);
         let s = self.0.as_str();
-        let parser = Parser::new(s, None, None, false, ParseMode::Format);
+        let parser = Parser::new(s, None, None, ParseMode::Format);
         let mut result = Ok(());
         for token in parser {
             match token {
@@ -650,7 +650,7 @@ impl<'tcx> OnUnimplementedFormatString {
         let empty_string = String::new();
 
         let s = self.0.as_str();
-        let parser = Parser::new(s, None, None, false, ParseMode::Format);
+        let parser = Parser::new(s, None, None, ParseMode::Format);
         let item_context = (options.get(&sym::ItemContext)).unwrap_or(&empty_string);
         parser
             .map(|p| match p {

library/core/src/macros/mod.rs

@@ -549,13 +549,12 @@ macro_rules! write {
 #[macro_export]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[cfg_attr(not(test), rustc_diagnostic_item = "writeln_macro")]
-#[allow_internal_unstable(format_args_nl)]
 macro_rules! writeln {
     ($dst:expr $(,)?) => {
         $crate::write!($dst, "\n")
     };
     ($dst:expr, $($arg:tt)*) => {
-        $dst.write_fmt($crate::format_args_nl!($($arg)*))
+        $dst.write_fmt($crate::format_args!("{}\n", $crate::format_args!($($arg)*)))
     };
 }
 
@@ -893,21 +892,6 @@ pub(crate) mod builtin {
         ($fmt:expr, $($args:tt)*) => {{ /* compiler built-in */ }};
     }
 
-    /// Same as [`format_args`], but adds a newline in the end.
-    #[unstable(
-        feature = "format_args_nl",
-        issue = "none",
-        reason = "`format_args_nl` is only for internal \
-                  language use and is subject to change"
-    )]
-    #[allow_internal_unstable(fmt_internals)]
-    #[rustc_builtin_macro]
-    #[macro_export]
-    macro_rules! format_args_nl {
-        ($fmt:expr) => {{ /* compiler built-in */ }};
-        ($fmt:expr, $($args:tt)*) => {{ /* compiler built-in */ }};
-    }
-
     /// Inspects an environment variable at compile time.
     ///
     /// This macro will expand to the value of the named environment variable at

library/core/src/prelude/v1.rs

@@ -55,9 +55,8 @@ pub use crate::hash::macros::Hash;
 #[allow(deprecated)]
 #[doc(no_inline)]
 pub use crate::{
-    assert, cfg, column, compile_error, concat, concat_idents, env, file, format_args,
-    format_args_nl, include, include_bytes, include_str, line, log_syntax, module_path, option_env,
-    stringify, trace_macros,
+    assert, cfg, column, compile_error, concat, concat_idents, env, file, format_args, include,
+    include_bytes, include_str, line, log_syntax, module_path, option_env, stringify, trace_macros,
 };
 
 #[unstable(

library/std/src/lib.rs

@@ -343,7 +343,6 @@
 #![feature(core_panic)]
 #![feature(custom_test_frameworks)]
 #![feature(edition_panic)]
-#![feature(format_args_nl)]
 #![feature(get_many_mut)]
 #![feature(lazy_cell)]
 #![feature(log_syntax)]
@@ -621,8 +620,8 @@ pub use core::{
 #[allow(deprecated)]
 pub use core::{
     assert, assert_matches, cfg, column, compile_error, concat, concat_idents, const_format_args,
-    env, file, format_args, format_args_nl, include, include_bytes, include_str, line, log_syntax,
-    module_path, option_env, stringify, trace_macros,
+    env, file, format_args, include, include_bytes, include_str, line, log_syntax, module_path,
+    option_env, stringify, trace_macros,
 };
 
 #[unstable(

library/std/src/macros.rs

@@ -128,13 +128,13 @@ macro_rules! print {
 #[macro_export]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[cfg_attr(not(test), rustc_diagnostic_item = "println_macro")]
-#[allow_internal_unstable(print_internals, format_args_nl)]
+#[allow_internal_unstable(print_internals)]
 macro_rules! println {
     () => {
         $crate::print!("\n")
     };
     ($($arg:tt)*) => {{
-        $crate::io::_print($crate::format_args_nl!($($arg)*));
+        $crate::io::_print($crate::format_args!("{}\n", $crate::format_args!($($arg)*)));
     }};
 }
 
@@ -200,13 +200,13 @@ macro_rules! eprint {
 #[macro_export]
 #[stable(feature = "eprint", since = "1.19.0")]
 #[cfg_attr(not(test), rustc_diagnostic_item = "eprintln_macro")]
-#[allow_internal_unstable(print_internals, format_args_nl)]
+#[allow_internal_unstable(print_internals)]
 macro_rules! eprintln {
     () => {
         $crate::eprint!("\n")
     };
     ($($arg:tt)*) => {{
-        $crate::io::_eprint($crate::format_args_nl!($($arg)*));
+        $crate::io::_eprint($crate::format_args!("{}\n", $crate::format_args!($($arg)*)));
     }};
 }
 

library/std/src/prelude/v1.rs

@@ -39,9 +39,9 @@ pub use crate::result::Result::{self, Err, Ok};
 #[allow(deprecated)]
 #[doc(no_inline)]
 pub use core::prelude::v1::{
-    assert, cfg, column, compile_error, concat, concat_idents, env, file, format_args,
-    format_args_nl, include, include_bytes, include_str, line, log_syntax, module_path, option_env,
-    stringify, trace_macros, Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd,
+    assert, cfg, column, compile_error, concat, concat_idents, env, file, format_args, include,
+    include_bytes, include_str, line, log_syntax, module_path, option_env, stringify, trace_macros,
+    Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd,
 };
 
 #[unstable(

library/std/src/process.rs

@@ -2266,7 +2266,7 @@ impl<T: Termination, E: fmt::Debug> Termination for Result<T, E> {
         match self {
             Ok(val) => val.report(),
             Err(err) => {
-                io::attempt_print_to_stderr(format_args_nl!("Error: {err:?}"));
+                io::attempt_print_to_stderr(format_args!("Error: {err:?}\n"));
                 ExitCode::FAILURE
             }
         }

src/tools/clippy/clippy_utils/src/macros.rs

@@ -391,7 +391,7 @@ pub fn find_format_args(cx: &LateContext<'_>, start: &Expr<'_>, expn_id: ExpnId,
         if ctxt.outer_expn().is_descendant_of(expn_id) {
             if macro_backtrace(expr.span)
                 .map(|macro_call| cx.tcx.item_name(macro_call.def_id))
-                .any(|name| matches!(name, sym::const_format_args | sym::format_args | sym::format_args_nl))
+                .any(|name| matches!(name, sym::const_format_args | sym::format_args))
             {
                 ControlFlow::Break(expr)
             } else {

src/tools/clippy/tests/ui/explicit_write.fixed

@@ -23,22 +23,22 @@ fn main() {
         use std::io::Write;
         print!("test");
         eprint!("test");
-        println!("test");
-        eprintln!("test");
+        println!("{}\n", $crate::format_args!($($arg)*));
+        eprintln!("{}\n", $crate::format_args!($($arg)*));
         print!("test");
         eprint!("test");
 
         // including newlines
-        println!("test\ntest");
-        eprintln!("test\ntest");
+        println!("{}\n", $crate::format_args!($($arg)*));
+        eprintln!("{}\n", $crate::format_args!($($arg)*));
 
         let value = 1;
-        eprintln!("with {}", value);
-        eprintln!("with {} {}", 2, value);
-        eprintln!("with {value}");
-        eprintln!("macro arg {}", one!());
+        eprintln!("{}\n", $crate::format_args!($($arg)*));
+        eprintln!("{}\n", $crate::format_args!($($arg)*));
+        eprintln!("{}\n", $crate::format_args!($($arg)*));
+        eprintln!("{}\n", $crate::format_args!($($arg)*));
         let width = 2;
-        eprintln!("{:w$}", value, w = width);
+        eprintln!("{}\n", $crate::format_args!($($arg)*));
     }
     // these should not warn, different destination
     {