diff --git a/compiler/rustc_typeck/src/collect.rs b/compiler/rustc_typeck/src/collect.rs
index d6985f3bd4d63..fdab5afd9aca1 100644
--- a/compiler/rustc_typeck/src/collect.rs
+++ b/compiler/rustc_typeck/src/collect.rs
@@ -710,6 +710,14 @@ fn convert_item(tcx: TyCtxt<'_>, item_id: hir::HirId) {
             if let hir::ItemKind::Fn(..) = it.kind {
                 tcx.ensure().fn_sig(def_id);
             }
+            // Account for the `_` placeholder.
+            // We only check on `static` or `const` to avoid too many duplicated errors
+            // (see https://github.com/rust-lang/rust/issues/77428).
+            if matches!(it.kind, hir::ItemKind::Static(..) | hir::ItemKind::Const(..)) {
+                let mut visitor = PlaceholderHirTyCollector::default();
+                visitor.visit_item(it);
+                placeholder_type_error(tcx, None, &[], visitor.0, false);
+            }
         }
     }
 }
diff --git a/src/test/ui/error-codes/E0121.rs b/src/test/ui/error-codes/E0121.rs
index f8b4d61b32301..1b68be4ea96c0 100644
--- a/src/test/ui/error-codes/E0121.rs
+++ b/src/test/ui/error-codes/E0121.rs
@@ -1,6 +1,10 @@
 fn foo() -> _ { 5 } //~ ERROR E0121
 
 static BAR: _ = "test"; //~ ERROR E0121
+//~^ ERROR E0121
 
-fn main() {
-}
+const FOO: dyn Fn() -> _ = ""; //~ ERROR E0121
+
+static BOO: dyn Fn() -> _ = ""; //~ ERROR E0121
+
+fn main() {}
diff --git a/src/test/ui/error-codes/E0121.stderr b/src/test/ui/error-codes/E0121.stderr
index ad854837ae5bd..b46383b4a0ca4 100644
--- a/src/test/ui/error-codes/E0121.stderr
+++ b/src/test/ui/error-codes/E0121.stderr
@@ -16,6 +16,24 @@ LL | static BAR: _ = "test";
    |             not allowed in type signatures
    |             help: replace `_` with the correct type: `&str`
 
-error: aborting due to 2 previous errors
+error[E0121]: the type placeholder `_` is not allowed within types on item signatures
+  --> $DIR/E0121.rs:3:13
+   |
+LL | static BAR: _ = "test";
+   |             ^ not allowed in type signatures
+
+error[E0121]: the type placeholder `_` is not allowed within types on item signatures
+  --> $DIR/E0121.rs:6:24
+   |
+LL | const FOO: dyn Fn() -> _ = "";
+   |                        ^ not allowed in type signatures
+
+error[E0121]: the type placeholder `_` is not allowed within types on item signatures
+  --> $DIR/E0121.rs:8:25
+   |
+LL | static BOO: dyn Fn() -> _ = "";
+   |                         ^ not allowed in type signatures
+
+error: aborting due to 5 previous errors
 
 For more information about this error, try `rustc --explain E0121`.