Reduce verbosity of errors involving builtin macros

compiler/rustc_errors/src/emitter.rs

@@ -333,7 +333,9 @@ pub trait Emitter: Translate {
                     // are some which do actually involve macros.
                     ExpnKind::Inlined | ExpnKind::Desugaring(..) | ExpnKind::AstPass(..) => None,
 
-                    ExpnKind::Macro(macro_kind, name) => Some((macro_kind, name)),
+                    ExpnKind::Macro(macro_kind, name) => {
+                        Some((macro_kind, name, expn_data.builtin_name))
+                    }
                 }
             })
             .collect();
@@ -345,9 +347,9 @@ pub trait Emitter: Translate {
         self.render_multispans_macro_backtrace(span, children, backtrace);
 
         if !backtrace {
-            if let Some((macro_kind, name)) = has_macro_spans.first() {
+            if let Some((macro_kind, name, builtin_name)) = has_macro_spans.first() {
                 // Mark the actual macro this originates from
-                let and_then = if let Some((macro_kind, last_name)) = has_macro_spans.last()
+                let and_then = if let Some((macro_kind, last_name, _)) = has_macro_spans.last()
                     && last_name != name
                 {
                     let descr = macro_kind.descr();
@@ -364,12 +366,25 @@ pub trait Emitter: Translate {
                     (in Nightly builds, run with -Z macro-backtrace for more info)",
                 );
 
-                children.push(SubDiagnostic {
-                    level: Level::Note,
-                    message: vec![(DiagnosticMessage::Str(msg), Style::NoStyle)],
-                    span: MultiSpan::new(),
-                    render_span: None,
-                });
+                if let Some(
+                    "assert" | "bench" | "cfg" | "concat" | "concat_idents" | "env" | "format_args"
+                    | "format_args_nl" | "global_allocator" | "include_str" | "test",
+                ) = builtin_name.as_ref().map(|n| n.as_str())
+                {
+                    // We explicitly ignore these builtin macros and not show the line, as end
+                    // users will never care about these, the macros should be providing good
+                    // diagnostics always.
+                    // FIXME: we could include the builtin `derive` macros here, but we need to
+                    // audit every one of them before doing so to verify that they always produce
+                    // reasonable diagnostics that point at the macro use.
+                } else {
+                    children.push(SubDiagnostic {
+                        level: Level::Note,
+                        message: vec![(DiagnosticMessage::Str(msg), Style::NoStyle)],
+                        span: MultiSpan::new(),
+                        render_span: None,
+                    });
+                }
             }
         }
     }

compiler/rustc_expand/src/base.rs

@@ -858,6 +858,7 @@ impl SyntaxExtension {
         descr: Symbol,
         macro_def_id: Option<DefId>,
         parent_module: Option<DefId>,
+        builtin_name: Option<Symbol>,
     ) -> ExpnData {
         ExpnData::new(
             ExpnKind::Macro(self.macro_kind(), descr),
@@ -871,6 +872,7 @@ impl SyntaxExtension {
             self.allow_internal_unsafe,
             self.local_inner_macros,
             self.collapse_debuginfo,
+            builtin_name,
         )
     }
 }

compiler/rustc_resolve/src/macros.rs

@@ -292,6 +292,7 @@ impl<'a> ResolverExpand for Resolver<'a> {
                 fast_print_path(path),
                 def_id,
                 def_id.map(|def_id| self.macro_def_scope(def_id).nearest_parent_mod()),
+                ext.builtin_name,
             ),
             self.create_stable_hashing_context(),
         );

compiler/rustc_span/src/hygiene.rs

@@ -961,6 +961,9 @@ pub struct ExpnData {
     /// Should debuginfo for the macro be collapsed to the outermost expansion site (in other
     /// words, was the macro definition annotated with `#[collapse_debuginfo]`)?
     pub collapse_debuginfo: bool,
+    /// If this expansion comes from a builtin macro, this is the macro's name. Used when emitting
+    /// diagnostics to hide the line "this error originates in...".
+    pub builtin_name: Option<Symbol>,
 }
 
 impl !PartialEq for ExpnData {}
@@ -979,6 +982,7 @@ impl ExpnData {
         allow_internal_unsafe: bool,
         local_inner_macros: bool,
         collapse_debuginfo: bool,
+        builtin_name: Option<Symbol>,
     ) -> ExpnData {
         ExpnData {
             kind,
@@ -993,6 +997,7 @@ impl ExpnData {
             allow_internal_unsafe,
             local_inner_macros,
             collapse_debuginfo,
+            builtin_name,
         }
     }
 
@@ -1017,6 +1022,7 @@ impl ExpnData {
             allow_internal_unsafe: false,
             local_inner_macros: false,
             collapse_debuginfo: false,
+            builtin_name: None,
         }
     }
 

src/test/ui/allocator/not-an-allocator.stderr

@@ -7,7 +7,6 @@ LL | static A: usize = 0;
    |           ^^^^^ the trait `GlobalAlloc` is not implemented for `usize`
    |
    = help: the trait `GlobalAlloc` is implemented for `System`
-   = note: this error originates in the attribute macro `global_allocator` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0277]: the trait bound `usize: GlobalAlloc` is not satisfied
   --> $DIR/not-an-allocator.rs:2:11
@@ -18,7 +17,6 @@ LL | static A: usize = 0;
    |           ^^^^^ the trait `GlobalAlloc` is not implemented for `usize`
    |
    = help: the trait `GlobalAlloc` is implemented for `System`
-   = note: this error originates in the attribute macro `global_allocator` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0277]: the trait bound `usize: GlobalAlloc` is not satisfied
   --> $DIR/not-an-allocator.rs:2:11
@@ -29,7 +27,6 @@ LL | static A: usize = 0;
    |           ^^^^^ the trait `GlobalAlloc` is not implemented for `usize`
    |
    = help: the trait `GlobalAlloc` is implemented for `System`
-   = note: this error originates in the attribute macro `global_allocator` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0277]: the trait bound `usize: GlobalAlloc` is not satisfied
   --> $DIR/not-an-allocator.rs:2:11
@@ -40,7 +37,6 @@ LL | static A: usize = 0;
    |           ^^^^^ the trait `GlobalAlloc` is not implemented for `usize`
    |
    = help: the trait `GlobalAlloc` is implemented for `System`
-   = note: this error originates in the attribute macro `global_allocator` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to 4 previous errors
 

src/test/ui/allocator/two-allocators.stderr

@@ -7,8 +7,6 @@ LL | #[global_allocator]
    | ------------------- in this procedural macro expansion
 LL | static B: System = System;
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot define a new global allocator
-   |
-   = note: this error originates in the attribute macro `global_allocator` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to previous error
 

src/test/ui/attributes/extented-attribute-macro-error.stderr

@@ -3,8 +3,6 @@ error: couldn't read the file
    |
 LL | #![doc = include_str!("../not_existing_file.md")]
    |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: this error originates in the macro `include_str` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to previous error
 

src/test/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 previous error
 

src/test/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 = 0;

src/test/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 = 0;

src/test/ui/borrowck/borrowck-or-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 previous error
 

src/test/ui/borrowck/borrowck-while-break.stderr

@@ -8,8 +8,6 @@ LL |     while cond {
 ...
 LL |     println!("{}", v);
    |                    ^ `v` 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 previous error
 

src/test/ui/borrowck/issue-24267-flow-exit.stderr

@@ -7,7 +7,6 @@ LL |     loop { x = break; }
 LL |     println!("{}", x);
    |                    ^ `x` used here but it isn't initialized
    |
-   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
 help: consider assigning a value
    |
 LL |     let x: i32 = 0;
@@ -22,7 +21,6 @@ LL |     for _ in 0..10 { x = continue; }
 LL |     println!("{}", x);
    |                    ^ `x` used here but it isn't initialized
    |
-   = note: this error originates in the macro `$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: i32 = 0;

src/test/ui/borrowck/issue-64453.stderr

@@ -5,7 +5,6 @@ LL | static settings_dir: String = format!("");
    |                               ^^^^^^^^^^^
    |
    = help: add `#![feature(const_fmt_arguments_new)]` to the crate attributes to enable
-   = note: this error originates in the macro `$crate::__export::format_args` which comes from the expansion of the macro `format` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0015]: cannot call non-const fn `format` in statics
   --> $DIR/issue-64453.rs:4:31

src/test/ui/borrowck/suggest-assign-rvalue.stderr

@@ -19,7 +19,6 @@ LL |     let my_float: f32;
 LL |     println!("my_float: {}", my_float);
    |                              ^^^^^^^^ `my_float` used here but it isn't initialized
    |
-   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
 help: consider assigning a value
    |
 LL |     let my_float: f32 = 0.0;
@@ -33,7 +32,6 @@ LL |     let demo: Demo;
 LL |     println!("demo: {:?}", demo);
    |                            ^^^^ `demo` used here but it isn't initialized
    |
-   = note: this error originates in the macro `$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 demo: Demo = Default::default();
@@ -47,7 +45,6 @@ LL |     let demo_no: DemoNoDef;
 LL |     println!("demo_no: {:?}", demo_no);
    |                               ^^^^^^^ `demo_no` used here but it isn't initialized
    |
-   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
 help: consider assigning a value
    |
 LL |     let demo_no: DemoNoDef = todo!();
@@ -61,7 +58,6 @@ LL |     let arr: [i32; 5];
 LL |     println!("arr: {:?}", arr);
    |                           ^^^ `arr` used here but it isn't initialized
    |
-   = note: this error originates in the macro `$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 arr: [i32; 5] = todo!();
@@ -75,7 +71,6 @@ LL |     let foo: Vec<&str>;
 LL |     println!("foo: {:?}", foo);
    |                           ^^^ `foo` used here but it isn't initialized
    |
-   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
 help: consider assigning a value
    |
 LL |     let foo: Vec<&str> = vec![];
@@ -89,7 +84,6 @@ LL |     let my_string: String;
 LL |     println!("my_string: {}", my_string);
    |                               ^^^^^^^^^ `my_string` used here but it isn't initialized
    |
-   = note: this error originates in the macro `$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 my_string: String = Default::default();
@@ -103,7 +97,6 @@ LL |     let my_int: &i32;
 LL |     println!("my_int: {}", *my_int);
    |                            ^^^^^^^ `*my_int` used here but it isn't initialized
    |
-   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
 help: consider assigning a value
    |
 LL |     let my_int: &i32 = todo!();
@@ -117,7 +110,6 @@ LL |     let hello: &str;
 LL |     println!("hello: {}", hello);
    |                           ^^^^^ `hello` used here but it isn't initialized
    |
-   = note: this error originates in the macro `$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 hello: &str = todo!();
@@ -130,8 +122,6 @@ LL |     let never: !;
    |         ----- binding declared here but left uninitialized
 LL |     println!("never: {}", never);
    |                           ^^^^^ `never` 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)
 
 error: aborting due to 10 previous errors
 

src/test/ui/closures/2229_closure_analysis/diagnostics/arrays.stderr

@@ -81,8 +81,6 @@ LL |     println!("{}", arr[3]);
 ...
 LL |     c();
    |     - mutable borrow later used here
-   |
-   = 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[E0502]: cannot borrow `arr` as immutable because it is also borrowed as mutable
   --> $DIR/arrays.rs:73:24

src/test/ui/closures/2229_closure_analysis/diagnostics/box.stderr

@@ -25,8 +25,6 @@ LL |     println!("{}", e.0.0.m.x);
 LL |
 LL |     c();
    |     - mutable borrow later used here
-   |
-   = 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[E0506]: cannot assign to `e.0.0.m.x` because it is borrowed
   --> $DIR/box.rs:55:5

src/test/ui/closures/2229_closure_analysis/diagnostics/repr_packed.stderr

@@ -9,7 +9,6 @@ LL |         println!("{}", foo.x);
    = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
    = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers)
    = note: `#[deny(unaligned_references)]` on by default
-   = 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 previous error
 
@@ -25,5 +24,4 @@ LL |         println!("{}", foo.x);
    = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
    = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers)
    = note: `#[deny(unaligned_references)]` on by default
-   = 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)
 

src/test/ui/closures/2229_closure_analysis/diagnostics/simple-struct-min-capture.stderr

@@ -13,8 +13,6 @@ LL |     println!("{:?}", p);
 LL |
 LL |     c();
    |     - mutable borrow later used here
-   |
-   = 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 previous error
 

src/test/ui/codemap_tests/bad-format-args.stderr

@@ -3,8 +3,6 @@ error: requires at least a format string argument
    |
 LL |     format!();
    |     ^^^^^^^^^
-   |
-   = note: this error originates in the macro `$crate::__export::format_args` which comes from the expansion of the macro `format` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: expected `,`, found `1`
   --> $DIR/bad-format-args.rs:3:16

src/test/ui/codemap_tests/issue-28308.stderr

@@ -3,8 +3,6 @@ error[E0600]: cannot apply unary operator `!` to type `&'static str`
    |
 LL |     assert!("foo");
    |     ^^^^^^^^^^^^^^ cannot apply unary operator `!`
-   |
-   = note: this error originates in the macro `assert` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to previous error
 

src/test/ui/codemap_tests/tab_3.stderr

@@ -11,7 +11,6 @@ LL |         println!("{:?}", some_vec);
    |
 note: `into_iter` takes ownership of the receiver `self`, which moves `some_vec`
   --> $SRC_DIR/core/src/iter/traits/collect.rs:LL:COL
-   = note: this error originates in the macro `$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: you can `clone` the value and consume it, but this might not be your desired behavior
    |
 LL |     some_vec.clone().into_iter();

src/test/ui/const-ptr/forbidden_slices.32bit.stderr

@@ -124,7 +124,6 @@ note: inside `R1`
    |
 LL | pub static R1: &[()] = unsafe { from_ptr_range(ptr::null()..ptr::null()) };
    |                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   = note: this error originates in the macro `assert` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0080]: could not evaluate static initializer
   --> $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL

src/test/ui/const-ptr/forbidden_slices.64bit.stderr

@@ -124,7 +124,6 @@ note: inside `R1`
    |
 LL | pub static R1: &[()] = unsafe { from_ptr_range(ptr::null()..ptr::null()) };
    |                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   = note: this error originates in the macro `assert` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0080]: could not evaluate static initializer
   --> $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL