Restrict error code length to 80 columns

The global restriction is 100, but since error codes are printed out via
--explain we want to restrict them to just 80 columns.

Author: Mark-Simulacrum

src/librustc/error_codes.rs

@@ -1,7 +1,8 @@
 // Error messages for EXXXX errors.
-// Each message should start and end with a new line, and be wrapped to 80 characters.
-// In vim you can `:set tw=80` and use `gq` to wrap paragraphs. Use `:set tw=0` to disable.
-register_long_diagnostics! {
+// Each message should start and end with a new line, and be wrapped to 80
+// characters.  In vim you can `:set tw=80` and use `gq` to wrap paragraphs. Use
+// `:set tw=0` to disable.
+syntax::register_diagnostics! {
 E0038: r##"
 Trait objects like `Box<Trait>` can only be constructed when certain
 requirements are satisfied by the trait in question.
@@ -2206,7 +2207,8 @@ register_diagnostics! {
 //  E0305, // expected constant
     E0311, // thing may not live long enough
     E0312, // lifetime of reference outlives lifetime of borrowed content
-    E0313, // lifetime of borrowed pointer outlives lifetime of captured variable
+    E0313, // lifetime of borrowed pointer outlives lifetime of captured
+           // variable
     E0314, // closure outlives stack frame
     E0315, // cannot invoke closure outside of its lifetime
     E0316, // nested quantification of lifetimes
@@ -2223,12 +2225,13 @@ register_diagnostics! {
     E0483, // lifetime of operand does not outlive the operation
     E0484, // reference is not valid at the time of borrow
     E0485, // automatically reference is not valid at the time of borrow
-    E0486, // type of expression contains references that are not valid during...
+    E0486, // type of expression contains references that are not valid during..
     E0487, // unsafe use of destructor: destructor might be called while...
     E0488, // lifetime of variable does not enclose its declaration
     E0489, // type/lifetime parameter not in scope here
     E0490, // a value of type `..` is borrowed for too long
-    E0495, // cannot infer an appropriate lifetime due to conflicting requirements
+    E0495, // cannot infer an appropriate lifetime due to conflicting
+           // requirements
     E0566, // conflicting representation hints
     E0623, // lifetime mismatch where both parameters are anonymous regions
     E0628, // generators cannot have explicit parameters
@@ -2239,7 +2242,8 @@ register_diagnostics! {
     E0688, // in-band lifetimes cannot be mixed with explicit lifetime binders
     E0697, // closures cannot be static
     E0707, // multiple elided lifetimes used in arguments of `async fn`
-    E0708, // `async` non-`move` closures with parameters are not currently supported
+    E0708, // `async` non-`move` closures with parameters are not currently
+           // supported
     E0709, // multiple different lifetimes used in arguments of `async fn`
     E0710, // an unknown tool name found in scoped lint
     E0711, // a feature has been declared with conflicting stability attributes

src/librustc_metadata/error_codes.rs

@@ -97,5 +97,6 @@ register_diagnostics! {
     E0464, // multiple matching crates for `..`
     E0465, // multiple .. candidates for `..` found
     E0519, // local crate and dependency have same (crate-name, disambiguator)
-    E0523, // two dependencies have same (crate-name, disambiguator) but different SVH
+    // two dependencies have same (crate-name, disambiguator) but different SVH
+    E0523,
 }

src/librustc_typeck/error_codes.rs

@@ -4930,15 +4930,16 @@ register_diagnostics! {
 //  E0245, // not a trait
 //  E0246, // invalid recursive type
 //  E0247,
-//  E0248, // value used as a type, now reported earlier during resolution as E0412
+//  E0248, // value used as a type, now reported earlier during resolution
+           // as E0412
 //  E0249,
 //  E0319, // trait impls for defaulted traits allowed just for structs/enums
 //  E0372, // coherence not object safe
     E0377, // the trait `CoerceUnsized` may only be implemented for a coercion
            // between structures with the same definition
 //  E0558, // replaced with a generic attribute input check
     E0533, // `{}` does not name a unit variant, unit struct or a constant
-//  E0563, // cannot determine a type for this `impl Trait`: {} // removed in 6383de15
+//  E0563, // cannot determine a type for this `impl Trait` removed in 6383de15
     E0564, // only named lifetimes are allowed in `impl Trait`,
            // but `{}` was found in the type `{}`
     E0587, // type has conflicting packed and align representation hints
@@ -4947,8 +4948,8 @@ register_diagnostics! {
 //  E0612, // merged into E0609
 //  E0613, // Removed (merged with E0609)
     E0627, // yield statement outside of generator literal
-    E0632, // cannot provide explicit type parameters when `impl Trait` is used in
-           // argument position.
+    E0632, // cannot provide explicit type parameters when `impl Trait` is used
+           // in argument position.
     E0634, // type has conflicting packed representaton hints
     E0640, // infer outlives requirements
     E0641, // cannot cast to/from a pointer with an unknown kind

src/libsyntax/error_codes.rs

@@ -1,7 +1,8 @@
 // Error messages for EXXXX errors.
-// Each message should start and end with a new line, and be wrapped to 80 characters.
-// In vim you can `:set tw=80` and use `gq` to wrap paragraphs. Use `:set tw=0` to disable.
-register_long_diagnostics! {
+// Each message should start and end with a new line, and be wrapped to 80
+// characters.  In vim you can `:set tw=80` and use `gq` to wrap paragraphs. Use
+// `:set tw=0` to disable.
+register_diagnostics! {
 
 E0178: r##"
 In types, the `+` type operator has low precedence, so it is often necessary
@@ -432,15 +433,19 @@ register_diagnostics! {
     E0546, // missing 'feature'
     E0547, // missing 'issue'
 //  E0548, // replaced with a generic attribute input check
-    E0549, // rustc_deprecated attribute must be paired with either stable or unstable attribute
+    // rustc_deprecated attribute must be paired with either stable or unstable
+    // attribute
+    E0549,
     E0550, // multiple deprecated attributes
     E0551, // incorrect meta item
     E0553, // multiple rustc_const_unstable attributes
 //  E0555, // replaced with a generic attribute input check
     E0556, // malformed feature, expected just one word
     E0584, // file for module `..` found at both .. and ..
     E0629, // missing 'feature' (rustc_const_unstable)
-    E0630, // rustc_const_unstable attribute must be paired with stable/unstable attribute
+    // rustc_const_unstable attribute must be paired with stable/unstable
+    // attribute
+    E0630,
     E0693, // incorrect `repr(align)` attribute format
     E0694, // an unknown tool name found in scoped attributes
     E0703, // invalid ABI

src/libsyntax/feature_gate/removed.rs

@@ -94,6 +94,11 @@ declare_features! (
     /// Allows defining `existential type`s.
     (removed, existential_type, "1.38.0", Some(63063), None,
      Some("removed in favor of `#![feature(type_alias_impl_trait)]`")),
+    /// Allows using the macros:
+    /// + `__diagnostic_used`
+    /// + `__register_diagnostic`
+    /// +`__build_diagnostic_array`
+    (removed, rustc_diagnostic_macros, "1.38.0", None, None, None),
 
     // -------------------------------------------------------------------------
     // feature-group-end: removed features

src/libsyntax_ext/error_codes.rs

@@ -1,9 +1,10 @@
 use syntax::register_long_diagnostics;
 
 // Error messages for EXXXX errors.
-// Each message should start and end with a new line, and be wrapped to 80 characters.
-// In vim you can `:set tw=80` and use `gq` to wrap paragraphs. Use `:set tw=0` to disable.
-register_long_diagnostics! {
+// Each message should start and end with a new line, and be wrapped to 80
+// characters.  In vim you can `:set tw=80` and use `gq` to wrap paragraphs. Use
+// `:set tw=0` to disable.
+syntax::register_diagnostics! {
 E0660: r##"
 The argument to the `asm` macro is not well-formed.
 

src/tools/tidy/src/style.rs

@@ -15,6 +15,7 @@
 
 use std::path::Path;
 
+const ERROR_CODE_COLS: usize = 80;
 const COLS: usize = 100;
 
 const LINES: usize = 3000;
@@ -51,7 +52,13 @@ enum LIUState {
 /// Lines of this form are allowed to be overlength, because Markdown
 /// offers no way to split a line in the middle of a URL, and the lengths
 /// of URLs to external references are beyond our control.
-fn line_is_url(line: &str) -> bool {
+fn line_is_url(columns: usize, line: &str) -> bool {
+    // more basic check for error_codes.rs, to avoid complexity in implementing two state machines
+    if columns == ERROR_CODE_COLS {
+        return line.starts_with("[") &&
+            line.contains("]:") && line.contains("http");
+    }
+
     use self::LIUState::*;
     let mut state: LIUState = EXP_COMMENT_START;
     let is_url = |w: &str| w.starts_with("http://") || w.starts_with("https://");
@@ -75,7 +82,7 @@ fn line_is_url(line: &str) -> bool {
                 => state = EXP_END,
 
             (_, w)
-                if w.len() > COLS && is_url(w)
+                if w.len() > columns && is_url(w)
                 => state = EXP_END,
 
             (_, _) => {}
@@ -88,8 +95,8 @@ fn line_is_url(line: &str) -> bool {
 /// Returns `true` if `line` is allowed to be longer than the normal limit.
 /// Currently there is only one exception, for long URLs, but more
 /// may be added in the future.
-fn long_line_is_ok(line: &str) -> bool {
-    if line_is_url(line) {
+fn long_line_is_ok(max_columns: usize, line: &str) -> bool {
+    if line_is_url(max_columns, line) {
         return true;
     }
 
@@ -144,6 +151,12 @@ pub fn check(path: &Path, bad: &mut bool) {
             tidy_error!(bad, "{}: empty file", file.display());
         }
 
+        let max_columns = if filename == "error_codes.rs" {
+            ERROR_CODE_COLS
+        } else {
+            COLS
+        };
+
         let can_contain = contents.contains("// ignore-tidy-") ||
             contents.contains("# ignore-tidy-");
         let mut skip_cr = contains_ignore_directive(can_contain, &contents, "cr");
@@ -162,11 +175,12 @@ pub fn check(path: &Path, bad: &mut bool) {
             let mut err = |msg: &str| {
                 tidy_error!(bad, "{}:{}: {}", file.display(), i + 1, msg);
             };
-            if line.chars().count() > COLS && !long_line_is_ok(line) {
+            if line.chars().count() > max_columns &&
+                !long_line_is_ok(max_columns, line) {
                 suppressible_tidy_err!(
                     err,
                     skip_line_length,
-                    &format!("line longer than {} chars", COLS)
+                    &format!("line longer than {} chars", max_columns)
                 );
             }
             if line.contains('\t') {