rustc_hir_analysis: add a helper to check function the signature mismatches

This function is now used to check `#[panic_handler]`, `start` lang item, `main`, `#[start]` and intrinsic functions.

The diagnosis produced are now closer to the ones produced by trait/impl method signature mismatch.

1 files changed, 1 insertions, 25 deletions

diff --git a/compiler/rustc_hir_analysis/src/lib.rs b/compiler/rustc_hir_analysis/src/lib.rs
index ef788935efb..03963925d3d 100644
--- a/compiler/rustc_hir_analysis/src/lib.rs
+++ b/compiler/rustc_hir_analysis/src/lib.rs
@@ -99,7 +99,6 @@ use rustc_errors::ErrorGuaranteed;
 use rustc_errors::{DiagnosticMessage, SubdiagnosticMessage};
 use rustc_fluent_macro::fluent_messages;
 use rustc_hir as hir;
-use rustc_infer::infer::TyCtxtInferExt;
 use rustc_middle::middle;
 use rustc_middle::query::Providers;
 use rustc_middle::ty::{self, Ty, TyCtxt};
@@ -107,8 +106,7 @@ use rustc_middle::util;
 use rustc_session::parse::feature_err;
 use rustc_span::{symbol::sym, Span, DUMMY_SP};
 use rustc_target::spec::abi::Abi;
-use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt as _;
-use rustc_trait_selection::traits::{self, ObligationCause, ObligationCtxt};
+use rustc_trait_selection::traits;
 
 use astconv::{AstConv, OnlySelfBounds};
 use bounds::Bounds;
@@ -151,28 +149,6 @@ fn require_c_abi_if_c_variadic(tcx: TyCtxt<'_>, decl: &hir::FnDecl<'_>, abi: Abi
     tcx.sess.emit_err(errors::VariadicFunctionCompatibleConvention { span, conventions });
 }
 
-fn require_same_types<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    cause: &ObligationCause<'tcx>,
-    param_env: ty::ParamEnv<'tcx>,
-    expected: Ty<'tcx>,
-    actual: Ty<'tcx>,
-) {
-    let infcx = &tcx.infer_ctxt().build();
-    let ocx = ObligationCtxt::new(infcx);
-    match ocx.eq(cause, param_env, expected, actual) {
-        Ok(()) => {
-            let errors = ocx.select_all_or_error();
-            if !errors.is_empty() {
-                infcx.err_ctxt().report_fulfillment_errors(&errors);
-            }
-        }
-        Err(err) => {
-            infcx.err_ctxt().report_mismatched_types(cause, expected, actual, err).emit();
-        }
-    }
-}
-
 pub fn provide(providers: &mut Providers) {
     collect::provide(providers);
     coherence::provide(providers);