make the lint early-pass

Author: ada4a

clippy_lints/src/let_with_type_underscore.rs

@@ -1,9 +1,9 @@
 use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::is_from_proc_macro;
 use clippy_utils::source::{IntoSpan, SpanRangeExt};
+use rustc_ast::{Local, TyKind};
 use rustc_errors::Applicability;
-use rustc_hir::{LetStmt, TyKind};
-use rustc_lint::{LateContext, LateLintPass};
+use rustc_lint::{EarlyContext, EarlyLintPass, LintContext};
 use rustc_session::declare_lint_pass;
 
 declare_clippy_lint! {
@@ -26,14 +26,14 @@ declare_clippy_lint! {
 }
 declare_lint_pass!(UnderscoreTyped => [LET_WITH_TYPE_UNDERSCORE]);
 
-impl<'tcx> LateLintPass<'tcx> for UnderscoreTyped {
-    fn check_local(&mut self, cx: &LateContext<'tcx>, local: &'tcx LetStmt<'_>) {
-        if let Some(ty) = local.ty // Ensure that it has a type defined
-            && let TyKind::Infer(()) = &ty.kind // that type is '_'
+impl EarlyLintPass for UnderscoreTyped {
+    fn check_local<'tcx>(&mut self, cx: &EarlyContext<'tcx>, local: &Local) {
+        if let Some(ty) = &local.ty // Ensure that it has a type defined
+            && let TyKind::Infer = ty.kind // that type is '_'
             && local.span.eq_ctxt(ty.span)
-            && let sm = cx.tcx.sess.source_map()
+            && let sm = cx.sess().source_map()
             && !local.span.in_external_macro(sm)
-            && !is_from_proc_macro(cx, ty)
+            && !is_from_proc_macro(cx, &**ty)
         {
             let span_to_remove = sm
                 .span_extend_to_prev_char_before(ty.span, ':', true)

clippy_lints/src/lib.rs

@@ -742,7 +742,7 @@ pub fn register_lint_passes(store: &mut rustc_lint::LintStore, conf: &'static Co
     store.register_late_pass(|_| Box::new(missing_assert_message::MissingAssertMessage));
     store.register_late_pass(|_| Box::new(needless_maybe_sized::NeedlessMaybeSized));
     store.register_late_pass(|_| Box::new(redundant_async_block::RedundantAsyncBlock));
-    store.register_late_pass(|_| Box::new(let_with_type_underscore::UnderscoreTyped));
+    store.register_early_pass(|| Box::new(let_with_type_underscore::UnderscoreTyped));
     store.register_late_pass(move |_| Box::new(manual_main_separator_str::ManualMainSeparatorStr::new(conf)));
     store.register_late_pass(|_| Box::new(unnecessary_struct_initialization::UnnecessaryStruct));
     store.register_late_pass(move |_| Box::new(unnecessary_box_returns::UnnecessaryBoxReturns::new(conf)));