diagnostics: hide expansion of builtin-like macros

Author: mejrs

compiler/rustc_errors/src/emitter.rs

@@ -24,7 +24,7 @@ use rustc_lexer;
 use rustc_lint_defs::pluralize;
 use rustc_span::hygiene::{ExpnKind, MacroKind};
 use rustc_span::source_map::SourceMap;
-use rustc_span::{FileLines, FileName, SourceFile, Span, char_width, str_width};
+use rustc_span::{FileLines, FileName, SourceFile, Span, char_width, str_width, sym};
 use termcolor::{Buffer, BufferWriter, Color, ColorChoice, ColorSpec, StandardStream, WriteColor};
 use tracing::{debug, instrument, trace, warn};
 
@@ -297,9 +297,16 @@ pub trait Emitter: Translate {
                     // are some which do actually involve macros.
                     ExpnKind::Desugaring(..) | ExpnKind::AstPass(..) => None,
 
-                    ExpnKind::Macro(macro_kind, name) => {
-                        Some((macro_kind, name, expn_data.hide_backtrace))
-                    }
+                    ExpnKind::Macro(macro_kind, name) => Some((
+                        macro_kind,
+                        name,
+                        expn_data.hide_backtrace
+                            || expn_data.allow_internal_unstable.is_some_and(|aiu| {
+                                aiu.contains(&sym::fmt_internals)
+                                    || aiu.contains(&sym::print_internals)
+                                    || aiu.contains(&sym::liballoc_internals)
+                            }),
+                    )),
                 }
             })
             .collect();
@@ -311,8 +318,9 @@ pub trait Emitter: Translate {
         self.render_multispans_macro_backtrace(span, children, backtrace);
 
         if !backtrace {
-            // Skip builtin macros, as their expansion isn't relevant to the end user. This includes
-            // actual intrinsics, like `asm!`.
+            // Skip some special macros, as their expansion isn't relevant to the end user.
+            // This includes actual intrinsics and builtins like `asm!`, as well as macros
+            // that contain implementation details like the formatting macros
             if let Some((macro_kind, name, _)) = has_macro_spans.first()
                 && let Some((_, _, false)) = has_macro_spans.last()
             {

compiler/rustc_span/src/symbol.rs

@@ -1007,6 +1007,7 @@ symbols! {
         fmaf64,
         fmt,
         fmt_debug,
+        fmt_internals,
         fmul_algebraic,
         fmul_fast,
         fmuladdf128,
@@ -1240,6 +1241,7 @@ symbols! {
         let_else,
         lhs,
         lib,
+        liballoc_internals,
         libc,
         lifetime,
         lifetime_capture_rules_2024,
@@ -1623,6 +1625,7 @@ symbols! {
         prelude_import,
         preserves_flags,
         prfchw_target_feature,
+        print_internals,
         print_macro,
         println_macro,
         proc_dash_macro: "proc-macro",

tests/ui/asm/parse-error.stderr

@@ -193,16 +193,12 @@ error: asm template must be a string literal
    |
 LL |         asm!(format!("{{{}}}", 0), in(reg) foo);
    |              ^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: this error originates in the macro `format` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: asm template must be a string literal
   --> $DIR/parse-error.rs:86:21
    |
 LL |         asm!("{1}", format!("{{{}}}", 0), in(reg) foo, out(reg) bar);
    |                     ^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: this error originates in the macro `format` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: _ cannot be used for input operands
   --> $DIR/parse-error.rs:88:28
@@ -357,16 +353,12 @@ error: asm template must be a string literal
    |
 LL | global_asm!(format!("{{{}}}", 0), const FOO);
    |             ^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: this error originates in the macro `format` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: asm template must be a string literal
   --> $DIR/parse-error.rs:143:20
    |
 LL | global_asm!("{1}", format!("{{{}}}", 0), const FOO, const BAR);
    |                    ^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: this error originates in the macro `format` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: the `in` operand cannot be used with `global_asm!`
   --> $DIR/parse-error.rs:146:19

tests/ui/asm/x86_64/type-check-2.stderr

@@ -21,7 +21,6 @@ LL |         asm!("{}", in(reg) vec![0]);
    |                            ^^^^^^^
    |
    = note: only integers, floats, SIMD vectors, pointers and function pointers can be used as arguments for inline assembly
-   = note: this error originates in the macro `vec` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: cannot use value of type `(i32, i32, i32)` for inline assembly
   --> $DIR/type-check-2.rs:52:28

tests/ui/async-await/unreachable-lint-2.stderr

@@ -11,7 +11,6 @@ note: the lint level is defined here
    |
 LL | #![deny(unreachable_code)]
    |         ^^^^^^^^^^^^^^^^
-   = note: this error originates in the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to 1 previous error
 

tests/ui/borrowck/alias-liveness/higher-ranked-outlives-for-capture.stderr

@@ -8,8 +8,6 @@ LL |     test(&vec![])
    |     argument requires that borrow lasts for `'static`
 LL | }
    | - temporary value is freed at the end of this statement
-   |
-   = note: this error originates in the macro `vec` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to 1 previous error
 

tests/ui/borrowck/borrowck-and-init.stderr

@@ -8,8 +8,6 @@ LL |     println!("{}", false && { i = 5; true });
    |                               ----- binding initialized here in some conditions
 LL |     println!("{}", i);
    |                    ^ `i` used here but it is possibly-uninitialized
-   |
-   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to 1 previous error
 

tests/ui/borrowck/borrowck-borrowed-uniq-rvalue-2.stderr

@@ -8,7 +8,6 @@ LL |     let x = defer(&vec!["Goodbye", "world!"]);
 LL |     x.x[0];
    |     ------ borrow later used here
    |
-   = note: this error originates in the macro `vec` (in Nightly builds, run with -Z macro-backtrace for more info)
 help: consider using a `let` binding to create a longer lived value
    |
 LL ~     let binding = vec!["Goodbye", "world!"];

tests/ui/borrowck/borrowck-break-uninit-2.stderr

@@ -7,7 +7,6 @@ LL |     let x: isize;
 LL |     println!("{}", x);
    |                    ^ `x` used here but it isn't initialized
    |
-   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
 help: consider assigning a value
    |
 LL |     let x: isize = 42;

tests/ui/borrowck/borrowck-break-uninit.stderr

@@ -7,7 +7,6 @@ LL |     let x: isize;
 LL |     println!("{}", x);
    |                    ^ `x` used here but it isn't initialized
    |
-   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
 help: consider assigning a value
    |
 LL |     let x: isize = 42;