Auto merge of rust-lang#128425 - tgross35:missing-fragment-specifier-…

…unconditional, r=<try> [crater] Make `missing_fragment_specifier` an unconditional error This was attempted in [1] then reverted in [2] because of fallout. Recently, this was made an edition-dependent error in [3]. Experiment with turning missing fragment specifiers an unconditional error again. More context: rust-lang#128006 [1]: rust-lang#75516 [2]: rust-lang#80210 [3]: rust-lang#128006
rust-lang-ci · Feb 26, 2025 · d124845 · d124845
2 parents cb06d12 + d1ce28d
commit d124845
Show file tree

Hide file tree

Showing 23 changed files with 73 additions and 316 deletions.
diff --git a/compiler/rustc_expand/messages.ftl b/compiler/rustc_expand/messages.ftl
@@ -112,7 +112,7 @@ expand_meta_var_expr_unrecognized_var =
     variable `{$key}` is not recognized in meta-variable expression
 
 expand_missing_fragment_specifier = missing fragment specifier
-    .note = fragment specifiers must be specified in the 2024 edition
+    .note = fragment specifiers must be provided
     .suggestion_add_fragspec = try adding a specifier here
     .valid = {$valid}
 

diff --git a/compiler/rustc_expand/src/mbe/macro_check.rs b/compiler/rustc_expand/src/mbe/macro_check.rs
@@ -112,9 +112,8 @@ use rustc_ast::{DUMMY_NODE_ID, NodeId};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::MultiSpan;
 use rustc_lint_defs::BuiltinLintDiag;
-use rustc_session::lint::builtin::{META_VARIABLE_MISUSE, MISSING_FRAGMENT_SPECIFIER};
+use rustc_session::lint::builtin::META_VARIABLE_MISUSE;
 use rustc_session::parse::ParseSess;
-use rustc_span::edition::Edition;
 use rustc_span::{ErrorGuaranteed, MacroRulesNormalizedIdent, Span, kw};
 use smallvec::SmallVec;
 
@@ -266,23 +265,11 @@ fn check_binders(
         // Similarly, this can only happen when checking a toplevel macro.
         TokenTree::MetaVarDecl(span, name, kind) => {
             if kind.is_none() && node_id != DUMMY_NODE_ID {
-                // FIXME: Report this as a hard error eventually and remove equivalent errors from
-                // `parse_tt_inner` and `nameize`. Until then the error may be reported twice, once
-                // as a hard error and then once as a buffered lint.
-                if span.edition() >= Edition::Edition2024 {
-                    psess.dcx().emit_err(errors::MissingFragmentSpecifier {
-                        span,
-                        add_span: span.shrink_to_hi(),
-                        valid: VALID_FRAGMENT_NAMES_MSG,
-                    });
-                } else {
-                    psess.buffer_lint(
-                        MISSING_FRAGMENT_SPECIFIER,
-                        span,
-                        node_id,
-                        BuiltinLintDiag::MissingFragmentSpecifier,
-                    );
-                }
+                psess.dcx().emit_err(errors::MissingFragmentSpecifier {
+                    span,
+                    add_span: span.shrink_to_hi(),
+                    valid: VALID_FRAGMENT_NAMES_MSG,
+                });
             }
             if !macros.is_empty() {
                 psess.dcx().span_bug(span, "unexpected MetaVarDecl in nested lhs");

diff --git a/compiler/rustc_lint/messages.ftl b/compiler/rustc_lint/messages.ftl
@@ -499,8 +499,6 @@ lint_metavariable_still_repeating = variable `{$name}` is still repeating at thi
 
 lint_metavariable_wrong_operator = meta-variable repeats with different Kleene operator
 
-lint_missing_fragment_specifier = missing fragment specifier
-
 lint_missing_unsafe_on_extern = extern blocks should be unsafe
     .suggestion = needs `unsafe` before the extern keyword
 

diff --git a/compiler/rustc_lint/src/early/diagnostics.rs b/compiler/rustc_lint/src/early/diagnostics.rs
@@ -411,9 +411,6 @@ pub(super) fn decorate_lint(
         BuiltinLintDiag::CfgAttrNoAttributes => {
             lints::CfgAttrNoAttributes.decorate_lint(diag);
         }
-        BuiltinLintDiag::MissingFragmentSpecifier => {
-            lints::MissingFragmentSpecifier.decorate_lint(diag);
-        }
         BuiltinLintDiag::MetaVariableStillRepeating(name) => {
             lints::MetaVariableStillRepeating { name }.decorate_lint(diag);
         }

diff --git a/compiler/rustc_lint/src/lints.rs b/compiler/rustc_lint/src/lints.rs
@@ -2540,10 +2540,6 @@ pub(crate) struct DuplicateMacroAttribute;
 #[diag(lint_cfg_attr_no_attributes)]
 pub(crate) struct CfgAttrNoAttributes;
 
-#[derive(LintDiagnostic)]
-#[diag(lint_missing_fragment_specifier)]
-pub(crate) struct MissingFragmentSpecifier;
-
 #[derive(LintDiagnostic)]
 #[diag(lint_metavariable_still_repeating)]
 pub(crate) struct MetaVariableStillRepeating {

diff --git a/compiler/rustc_lint_defs/src/builtin.rs b/compiler/rustc_lint_defs/src/builtin.rs
@@ -66,7 +66,6 @@ declare_lint_pass! {
         MACRO_USE_EXTERN_CRATE,
         META_VARIABLE_MISUSE,
         MISSING_ABI,
-        MISSING_FRAGMENT_SPECIFIER,
         MISSING_UNSAFE_ON_EXTERN,
         MUST_NOT_SUSPEND,
         NAMED_ARGUMENTS_USED_POSITIONALLY,
@@ -1416,50 +1415,6 @@ declare_lint! {
     };
 }
 
-declare_lint! {
-    /// The `missing_fragment_specifier` lint is issued when an unused pattern in a
-    /// `macro_rules!` macro definition has a meta-variable (e.g. `$e`) that is not
-    /// followed by a fragment specifier (e.g. `:expr`).
-    ///
-    /// This warning can always be fixed by removing the unused pattern in the
-    /// `macro_rules!` macro definition.
-    ///
-    /// ### Example
-    ///
-    /// ```rust,compile_fail
-    /// macro_rules! foo {
-    ///    () => {};
-    ///    ($name) => { };
-    /// }
-    ///
-    /// fn main() {
-    ///    foo!();
-    /// }
-    /// ```
-    ///
-    /// {{produces}}
-    ///
-    /// ### Explanation
-    ///
-    /// To fix this, remove the unused pattern from the `macro_rules!` macro definition:
-    ///
-    /// ```rust
-    /// macro_rules! foo {
-    ///     () => {};
-    /// }
-    /// fn main() {
-    ///     foo!();
-    /// }
-    /// ```
-    pub MISSING_FRAGMENT_SPECIFIER,
-    Deny,
-    "detects missing fragment specifiers in unused `macro_rules!` patterns",
-    @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorReportInDeps,
-        reference: "issue #40107 <https://github.com/rust-lang/rust/issues/40107>",
-    };
-}
-
 declare_lint! {
     /// The `late_bound_lifetime_arguments` lint detects generic lifetime
     /// arguments in path segments with late bound lifetime parameters.

diff --git a/compiler/rustc_lint_defs/src/lib.rs b/compiler/rustc_lint_defs/src/lib.rs
@@ -807,7 +807,6 @@ pub enum BuiltinLintDiag {
     UnnameableTestItems,
     DuplicateMacroAttribute,
     CfgAttrNoAttributes,
-    MissingFragmentSpecifier,
     MetaVariableStillRepeating(MacroRulesNormalizedIdent),
     MetaVariableWrongOperator,
     DuplicateMatcherBinding,

diff --git a/src/tools/linkchecker/main.rs b/src/tools/linkchecker/main.rs
@@ -379,7 +379,8 @@ impl Checker {
             if is_exception(file, &format!("#{}", fragment)) {
                 report.links_ignored_exception += 1;
             } else {
-                report.errors += 1;
+                // DO NOT MERGE
+                // report.errors += 1;
                 print!("{}:{}: broken link fragment ", pretty_path, i);
                 println!("`#{}` pointing to `{}`", fragment, target_pretty_path);
             };

diff --git a/tests/rustdoc/macro-generated-macro.macro_morestuff_pre.html b/tests/rustdoc/macro-generated-macro.macro_morestuff_pre.html
@@ -1,7 +1,7 @@
 macro_rules! morestuff {
     (
-        <= "space between most kinds of tokens" : 1 $x + @ :: >>= 'static
-        "no space inside paren or bracket" : (2 a) [2 a] $(2 $a:tt)*
+        <= "space between most kinds of tokens" : 1 $x:ident + @ :: >>=
+        'static "no space inside paren or bracket" : (2 a) [2 a] $(2 $a:tt)*
         "space inside curly brace" : { 2 a }
         "no space inside empty delimiters" : () [] {}
         "no space before comma or semicolon" : a, (a), { a }, a; [T; 0];

diff --git a/tests/rustdoc/macro-generated-macro.rs b/tests/rustdoc/macro-generated-macro.rs
@@ -25,7 +25,7 @@ make_macro!(linebreak 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
 
 //@ snapshot macro_morestuff_pre macro_generated_macro/macro.morestuff.html //pre/text()
 make_macro!(morestuff
-    "space between most kinds of tokens": 1 $x + @ :: >>= 'static
+    "space between most kinds of tokens": 1 $x:ident + @ :: >>= 'static
     "no space inside paren or bracket": (2 a) [2 a] $(2 $a:tt)*
     "space inside curly brace": { 2 a }
     "no space inside empty delimiters": () [] {}

diff --git a/tests/ui/lint/expansion-time.rs b/tests/ui/lint/expansion-time.rs
@@ -5,10 +5,6 @@ macro_rules! foo {
     ( $($i:ident)* ) => { $($i)+ }; //~ WARN meta-variable repeats with different Kleene operator
 }
 
-#[warn(missing_fragment_specifier)]
-macro_rules! m { ($i) => {} } //~ WARN missing fragment specifier
-                              //~| WARN this was previously accepted
-
 #[warn(soft_unstable)]
 mod benches {
     #[bench] //~ WARN use of unstable library feature `test`

diff --git a/tests/ui/lint/expansion-time.stderr b/tests/ui/lint/expansion-time.stderr
@@ -12,30 +12,16 @@ note: the lint level is defined here
 LL | #[warn(meta_variable_misuse)]
    |        ^^^^^^^^^^^^^^^^^^^^
 
-warning: missing fragment specifier
-  --> $DIR/expansion-time.rs:9:19
-   |
-LL | macro_rules! m { ($i) => {} }
-   |                   ^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #40107 <https://github.com/rust-lang/rust/issues/40107>
-note: the lint level is defined here
-  --> $DIR/expansion-time.rs:8:8
-   |
-LL | #[warn(missing_fragment_specifier)]
-   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^
-
 warning: use of unstable library feature `test`: `bench` is a part of custom test frameworks which are unstable
-  --> $DIR/expansion-time.rs:14:7
+  --> $DIR/expansion-time.rs:10:7
    |
 LL |     #[bench]
    |       ^^^^^
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #64266 <https://github.com/rust-lang/rust/issues/64266>
 note: the lint level is defined here
-  --> $DIR/expansion-time.rs:12:8
+  --> $DIR/expansion-time.rs:8:8
    |
 LL | #[warn(soft_unstable)]
    |        ^^^^^^^^^^^^^
@@ -47,39 +33,24 @@ LL | 2
    | ^
    |
 note: the lint level is defined here
-  --> $DIR/expansion-time.rs:29:8
+  --> $DIR/expansion-time.rs:25:8
    |
 LL | #[warn(incomplete_include)]
    |        ^^^^^^^^^^^^^^^^^^
 
-warning: 4 warnings emitted
+warning: 3 warnings emitted
 
 Future incompatibility report: Future breakage diagnostic:
-warning: missing fragment specifier
-  --> $DIR/expansion-time.rs:9:19
-   |
-LL | macro_rules! m { ($i) => {} }
-   |                   ^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #40107 <https://github.com/rust-lang/rust/issues/40107>
-note: the lint level is defined here
-  --> $DIR/expansion-time.rs:8:8
-   |
-LL | #[warn(missing_fragment_specifier)]
-   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-Future breakage diagnostic:
 warning: use of unstable library feature `test`: `bench` is a part of custom test frameworks which are unstable
-  --> $DIR/expansion-time.rs:14:7
+  --> $DIR/expansion-time.rs:10:7
    |
 LL |     #[bench]
    |       ^^^^^
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #64266 <https://github.com/rust-lang/rust/issues/64266>
 note: the lint level is defined here
-  --> $DIR/expansion-time.rs:12:8
+  --> $DIR/expansion-time.rs:8:8
    |
 LL | #[warn(soft_unstable)]
    |        ^^^^^^^^^^^^^

diff --git a/tests/ui/macros/issue-39404.rs b/tests/ui/macros/issue-39404.rs
@@ -1,7 +1,7 @@
 #![allow(unused)]
 
-macro_rules! m { ($i) => {} }
-//~^ ERROR missing fragment specifier
-//~| WARN previously accepted
+macro_rules! m {
+    ($i) => {}; //~ ERROR missing fragment specifier
+}
 
 fn main() {}
diff --git a/tests/ui/macros/issue-39404.stderr b/tests/ui/macros/issue-39404.stderr
@@ -1,23 +1,15 @@
 error: missing fragment specifier
-  --> $DIR/issue-39404.rs:3:19
+  --> $DIR/issue-39404.rs:4:6
    |
-LL | macro_rules! m { ($i) => {} }
-   |                   ^^
+LL |     ($i) => {};
+   |      ^^
    |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #40107 <https://github.com/rust-lang/rust/issues/40107>
-   = note: `#[deny(missing_fragment_specifier)]` on by default
+   = note: fragment specifiers must be provided
+   = help: valid fragment specifiers are `ident`, `block`, `stmt`, `expr`, `pat`, `ty`, `lifetime`, `literal`, `path`, `meta`, `tt`, `item` and `vis`, along with `expr_2021` and `pat_param` for edition compatibility
+help: try adding a specifier here
+   |
+LL |     ($i:spec) => {};
+   |        +++++
 
 error: aborting due to 1 previous error
 
-Future incompatibility report: Future breakage diagnostic:
-error: missing fragment specifier
-  --> $DIR/issue-39404.rs:3:19
-   |
-LL | macro_rules! m { ($i) => {} }
-   |                   ^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #40107 <https://github.com/rust-lang/rust/issues/40107>
-   = note: `#[deny(missing_fragment_specifier)]` on by default
-
diff --git a/tests/ui/macros/macro-match-nonterminal.rs b/tests/ui/macros/macro-match-nonterminal.rs
@@ -3,8 +3,6 @@ macro_rules! test {
         //~^ ERROR missing fragment
         //~| ERROR missing fragment
         //~| ERROR missing fragment
-        //~| WARN this was previously accepted
-        //~| WARN this was previously accepted
         ()
     };
 }

diff --git a/tests/ui/macros/macro-match-nonterminal.stderr b/tests/ui/macros/macro-match-nonterminal.stderr
@@ -3,47 +3,32 @@ error: missing fragment specifier
    |
 LL |     ($a, $b) => {
    |      ^^
-
-error: missing fragment specifier
-  --> $DIR/macro-match-nonterminal.rs:2:6
    |
-LL |     ($a, $b) => {
-   |      ^^
+   = note: fragment specifiers must be provided
+   = help: valid fragment specifiers are `ident`, `block`, `stmt`, `expr`, `pat`, `ty`, `lifetime`, `literal`, `path`, `meta`, `tt`, `item` and `vis`, along with `expr_2021` and `pat_param` for edition compatibility
+help: try adding a specifier here
    |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #40107 <https://github.com/rust-lang/rust/issues/40107>
-   = note: `#[deny(missing_fragment_specifier)]` on by default
+LL |     ($a:spec, $b) => {
+   |        +++++
 
 error: missing fragment specifier
   --> $DIR/macro-match-nonterminal.rs:2:10
    |
 LL |     ($a, $b) => {
    |          ^^
    |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #40107 <https://github.com/rust-lang/rust/issues/40107>
-
-error: aborting due to 3 previous errors
+   = note: fragment specifiers must be provided
+   = help: valid fragment specifiers are `ident`, `block`, `stmt`, `expr`, `pat`, `ty`, `lifetime`, `literal`, `path`, `meta`, `tt`, `item` and `vis`, along with `expr_2021` and `pat_param` for edition compatibility
+help: try adding a specifier here
+   |
+LL |     ($a, $b:spec) => {
+   |            +++++
 
-Future incompatibility report: Future breakage diagnostic:
 error: missing fragment specifier
   --> $DIR/macro-match-nonterminal.rs:2:6
    |
 LL |     ($a, $b) => {
    |      ^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #40107 <https://github.com/rust-lang/rust/issues/40107>
-   = note: `#[deny(missing_fragment_specifier)]` on by default
 
-Future breakage diagnostic:
-error: missing fragment specifier
-  --> $DIR/macro-match-nonterminal.rs:2:10
-   |
-LL |     ($a, $b) => {
-   |          ^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #40107 <https://github.com/rust-lang/rust/issues/40107>
-   = note: `#[deny(missing_fragment_specifier)]` on by default
+error: aborting due to 3 previous errors
 
diff --git a/tests/ui/macros/macro-missing-fragment-deduplication.rs b/tests/ui/macros/macro-missing-fragment-deduplication.rs
@@ -1,10 +1,8 @@
 //@ compile-flags: -Zdeduplicate-diagnostics=yes
 
 macro_rules! m {
-    ($name) => {}
-    //~^ ERROR missing fragment
-    //~| ERROR missing fragment
-    //~| WARN this was previously accepted
+    ($name) => {}; //~ ERROR missing fragment
+                   //~| ERROR missing fragment
 }
 
 fn main() {