Migrate 'invalid callee' diagnostic

compiler/rustc_hir_typeck/messages.ftl

@@ -56,8 +56,10 @@ hir_typeck_functional_record_update_on_non_struct =
 
 hir_typeck_help_set_edition_cargo = set `edition = "{$edition}"` in `Cargo.toml`
 hir_typeck_help_set_edition_standalone = pass `--edition {$edition}` to `rustc`
-hir_typeck_lang_start_expected_sig_note = the `start` lang item should have the signature `fn(fn() -> T, isize, *const *const u8, u8) -> isize`
 
+hir_typeck_invalid_callee = expected function, found {$ty}
+
+hir_typeck_lang_start_expected_sig_note = the `start` lang item should have the signature `fn(fn() -> T, isize, *const *const u8, u8) -> isize`
 hir_typeck_lang_start_incorrect_number_params = incorrect number of parameters for the `start` lang item
 hir_typeck_lang_start_incorrect_number_params_note_expected_count = the `start` lang item should have four parameters, but found {$found_param_count}
 

compiler/rustc_hir_typeck/src/callee.rs

@@ -3,7 +3,6 @@ use super::method::MethodCallee;
 use super::{Expectation, FnCtxt, TupleArgumentsFlag};
 
 use crate::errors;
-use crate::type_error_struct;
 use rustc_ast::util::parser::PREC_POSTFIX;
 use rustc_errors::{Applicability, Diagnostic, ErrorGuaranteed, StashKey};
 use rustc_hir as hir;
@@ -603,17 +602,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
 
         let callee_ty = self.resolve_vars_if_possible(callee_ty);
-        let mut err = type_error_struct!(
-            self.tcx.sess,
-            callee_expr.span,
-            callee_ty,
-            E0618,
-            "expected function, found {}",
-            match &unit_variant {
+        let mut err = self.tcx.sess.create_err(errors::InvalidCallee {
+            span: callee_expr.span,
+            ty: match &unit_variant {
                 Some((_, kind, path)) => format!("{kind} `{path}`"),
                 None => format!("`{callee_ty}`"),
             }
-        );
+        });
+        if callee_ty.references_error() {
+            err.downgrade_to_delayed_bug();
+        }
 
         self.identify_bad_closure_def_and_call(
             &mut err,

compiler/rustc_hir_typeck/src/errors.rs

@@ -282,6 +282,14 @@ impl HelpUseLatestEdition {
     }
 }
 
+#[derive(Diagnostic)]
+#[diag(hir_typeck_invalid_callee, code = "E0618")]
+pub struct InvalidCallee {
+    #[primary_span]
+    pub span: Span,
+    pub ty: String,
+}
+
 #[derive(Subdiagnostic)]
 pub enum OptionResultRefMismatch {
     #[suggestion(