session: use derive more

Signed-off-by: David Wood <[email protected]>

compiler/rustc_error_messages/locales/en-US/session.ftl

@@ -54,3 +54,7 @@ session_crate_name_empty = crate name must not be empty
 session_invalid_character_in_create_name = invalid character `{$character}` in crate name: `{$crate_name}`
 
 session_expr_parentheses_needed = parentheses are required to parse this as an expression
+
+session_skipping_const_checks = skipping const checks
+session_unleashed_feature_help_named = skipping check for `{$gate}` feature
+session_unleashed_feature_help_unnamed = skipping check that does not even have a feature gate

compiler/rustc_session/src/errors.rs

@@ -1,9 +1,7 @@
 use std::num::NonZeroU32;
 
 use crate::cgu_reuse_tracker::CguReuse;
-use rustc_errors::{
-    fluent, DiagnosticBuilder, ErrorGuaranteed, Handler, IntoDiagnostic, MultiSpan,
-};
+use rustc_errors::MultiSpan;
 use rustc_macros::Diagnostic;
 use rustc_span::{Span, Symbol};
 use rustc_target::spec::{SplitDebuginfo, StackProtector, TargetTriple};
@@ -148,24 +146,15 @@ pub struct CrateNameEmpty {
     pub span: Option<Span>,
 }
 
+#[derive(Diagnostic)]
+#[diag(session::invalid_character_in_create_name)]
 pub struct InvalidCharacterInCrateName<'a> {
+    #[primary_span]
     pub span: Option<Span>,
     pub character: char,
     pub crate_name: &'a str,
 }
 
-impl IntoDiagnostic<'_> for InvalidCharacterInCrateName<'_> {
-    fn into_diagnostic(self, sess: &Handler) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
-        let mut diag = sess.struct_err(fluent::session::invalid_character_in_create_name);
-        if let Some(sp) = self.span {
-            diag.set_span(sp);
-        }
-        diag.set_arg("character", self.character);
-        diag.set_arg("crate_name", self.crate_name);
-        diag
-    }
-}
-
 #[derive(Subdiagnostic)]
 #[multipart_suggestion(session::expr_parentheses_needed, applicability = "machine-applicable")]
 pub struct ExprParenthesesNeeded {
@@ -180,3 +169,25 @@ impl ExprParenthesesNeeded {
         ExprParenthesesNeeded { left: s.shrink_to_lo(), right: s.shrink_to_hi() }
     }
 }
+
+#[derive(Diagnostic)]
+#[diag(session::skipping_const_checks)]
+pub struct SkippingConstChecks {
+    #[subdiagnostic(eager)]
+    pub unleashed_features: Vec<UnleashedFeatureHelp>,
+}
+
+#[derive(Subdiagnostic)]
+pub enum UnleashedFeatureHelp {
+    #[help(session::unleashed_feature_help_named)]
+    Named {
+        #[primary_span]
+        span: Span,
+        gate: Symbol,
+    },
+    #[help(session::unleashed_feature_help_unnamed)]
+    Unnamed {
+        #[primary_span]
+        span: Span,
+    },
+}

compiler/rustc_session/src/session.rs

@@ -5,9 +5,10 @@ use crate::config::{self, CrateType, InstrumentCoverage, OptLevel, OutputType, S
 use crate::errors::{
     CannotEnableCrtStaticLinux, CannotMixAndMatchSanitizers, LinkerPluginToWindowsNotSupported,
     NotCircumventFeature, ProfileSampleUseFileDoesNotExist, ProfileUseFileDoesNotExist,
-    SanitizerCfiEnabled, SanitizerNotSupported, SanitizersNotSupported,
+    SanitizerCfiEnabled, SanitizerNotSupported, SanitizersNotSupported, SkippingConstChecks,
     SplitDebugInfoUnstablePlatform, StackProtectorNotSupportedForTarget,
-    TargetRequiresUnwindTables, UnstableVirtualFunctionElimination, UnsupportedDwarfVersion,
+    TargetRequiresUnwindTables, UnleashedFeatureHelp, UnstableVirtualFunctionElimination,
+    UnsupportedDwarfVersion,
 };
 use crate::parse::{add_feature_diagnostics, ParseSess};
 use crate::search_paths::{PathKind, SearchPath};
@@ -233,21 +234,19 @@ impl Session {
         if !unleashed_features.is_empty() {
             let mut must_err = false;
             // Create a diagnostic pointing at where things got unleashed.
-            // FIXME(#100717): needs eager translation/lists
-            #[allow(rustc::untranslatable_diagnostic)]
-            #[allow(rustc::diagnostic_outside_of_impl)]
-            let mut diag = self.struct_warn("skipping const checks");
-            for &(span, feature_gate) in unleashed_features.iter() {
-                // FIXME: `span_label` doesn't do anything, so we use "help" as a hack.
-                if let Some(gate) = feature_gate {
-                    diag.span_help(span, &format!("skipping check for `{gate}` feature"));
-                    // The unleash flag must *not* be used to just "hack around" feature gates.
-                    must_err = true;
-                } else {
-                    diag.span_help(span, "skipping check that does not even have a feature gate");
-                }
-            }
-            diag.emit();
+            self.emit_warning(SkippingConstChecks {
+                unleashed_features: unleashed_features
+                    .iter()
+                    .map(|(span, gate)| {
+                        gate.map(|gate| {
+                            must_err = true;
+                            UnleashedFeatureHelp::Named { span: *span, gate }
+                        })
+                        .unwrap_or(UnleashedFeatureHelp::Unnamed { span: *span })
+                    })
+                    .collect(),
+            });
+
             // If we should err, make sure we did.
             if must_err && self.has_errors().is_none() {
                 // We have skipped a feature gate, and not run into other errors... reject.