Simplify rustc_lint::EmitDiag by removing Lint from its API

Author: GuillaumeGomez

compiler/rustc_hir_analysis/src/lib.rs

@@ -153,26 +153,27 @@ fn emit_delayed_lint(lint: &DelayedLint, tcx: TyCtxt<'_>) {
         hir_id: rustc_hir::HirId,
         tcx: TyCtxt<'tcx>,
         span: Span,
+        lint: &'static rustc_lint::Lint,
     }
 
     impl rustc_lint::EmitDiag for DiagEmitter<'_> {
-        fn emit(
-            &self,
-            lint: &'static rustc_lint::Lint,
-            diag: impl for<'a> rustc_errors::Diagnostic<'a, ()>,
-        ) {
-            self.tcx.emit_node_span_lint(lint, self.hir_id, self.span, diag);
+        fn emit(&self, diag: impl for<'a> rustc_errors::Diagnostic<'a, ()>) {
+            self.tcx.emit_node_span_lint(self.lint, self.hir_id, self.span, diag);
         }
     }
 
     match lint {
         DelayedLint::AttributeParsing(attribute_lint) => {
             rustc_lint::decorate_attribute_lint(
-                &DiagEmitter { hir_id: attribute_lint.id, tcx, span: attribute_lint.span },
+                &DiagEmitter {
+                    hir_id: attribute_lint.id,
+                    tcx,
+                    span: attribute_lint.span,
+                    lint: attribute_lint.lint_id.lint,
+                },
                 tcx.sess,
                 Some(tcx),
                 &attribute_lint.kind,
-                attribute_lint.lint_id.lint,
             );
         }
     }

compiler/rustc_lint/src/early.rs

@@ -34,17 +34,18 @@ pub struct EarlyContextAndPass<'ecx, 'tcx, T: EarlyLintPass> {
 }
 
 pub trait EmitDiag {
-    fn emit(&self, lint: &'static Lint, diag: impl for<'a> Diagnostic<'a, ()>);
+    fn emit(&self, diag: impl for<'a> Diagnostic<'a, ()>);
 }
 
 struct DiagEmitter<'a, 'b> {
     ctx: &'a EarlyContext<'b>,
     span: Option<MultiSpan>,
+    lint: &'static Lint,
 }
 
 impl EmitDiag for DiagEmitter<'_, '_> {
-    fn emit(&self, lint: &'static Lint, diag: impl for<'a> Diagnostic<'a, ()>) {
-        self.ctx.opt_span_diag_lint(lint, self.span.clone(), diag);
+    fn emit(&self, diag: impl for<'a> Diagnostic<'a, ()>) {
+        self.ctx.opt_span_diag_lint(self.lint, self.span.clone(), diag);
     }
 }
 
@@ -55,11 +56,10 @@ impl<'ecx, 'tcx, T: EarlyLintPass> EarlyContextAndPass<'ecx, 'tcx, T> {
             match diagnostic {
                 DecorateDiagCompat::Builtin(b) => {
                     diagnostics::decorate_builtin_lint(
-                        &DiagEmitter { ctx: &self.context, span },
+                        &DiagEmitter { ctx: &self.context, span, lint: lint_id.lint },
                         self.context.sess(),
                         self.tcx,
                         b,
-                        lint_id.lint,
                     );
                 }
                 DecorateDiagCompat::Dynamic(d) => {