Auto merge of #87114 - cjgillot:abilint, r=estebank

Lint missing Abi in ast validation instead of lowering.

compiler/rustc_ast_lowering/src/lib.rs

@@ -53,7 +53,7 @@ use rustc_hir::definitions::{DefKey, DefPathData, Definitions};
 use rustc_hir::intravisit;
 use rustc_hir::{ConstArg, GenericArg, InferKind, ParamName};
 use rustc_index::vec::{Idx, IndexVec};
-use rustc_session::lint::builtin::{BARE_TRAIT_OBJECTS, MISSING_ABI};
+use rustc_session::lint::builtin::BARE_TRAIT_OBJECTS;
 use rustc_session::lint::{BuiltinLintDiagnostics, LintBuffer};
 use rustc_session::utils::{FlattenNonterminals, NtToTokenstream};
 use rustc_session::Session;
@@ -62,7 +62,6 @@ use rustc_span::hygiene::ExpnId;
 use rustc_span::source_map::{respan, CachingSourceMapView, DesugaringKind};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{Span, DUMMY_SP};
-use rustc_target::spec::abi::Abi;
 
 use smallvec::SmallVec;
 use std::collections::BTreeMap;
@@ -1361,7 +1360,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             }
             TyKind::BareFn(ref f) => self.with_in_scope_lifetime_defs(&f.generic_params, |this| {
                 this.with_anonymous_lifetime_mode(AnonymousLifetimeMode::PassThrough, |this| {
-                    let span = this.sess.source_map().next_point(t.span.shrink_to_lo());
                     hir::TyKind::BareFn(this.arena.alloc(hir::BareFnTy {
                         generic_params: this.lower_generic_params(
                             &f.generic_params,
@@ -1369,7 +1367,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                             ImplTraitContext::disallowed(),
                         ),
                         unsafety: this.lower_unsafety(f.unsafety),
-                        abi: this.lower_extern(f.ext, span, t.id),
+                        abi: this.lower_extern(f.ext),
                         decl: this.lower_fn_decl(&f.decl, None, false, None),
                         param_names: this.lower_fn_params_to_names(&f.decl),
                     }))
@@ -2749,26 +2747,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             }
         }
     }
-
-    fn maybe_lint_missing_abi(&mut self, span: Span, id: NodeId, default: Abi) {
-        // FIXME(davidtwco): This is a hack to detect macros which produce spans of the
-        // call site which do not have a macro backtrace. See #61963.
-        let is_macro_callsite = self
-            .sess
-            .source_map()
-            .span_to_snippet(span)
-            .map(|snippet| snippet.starts_with("#["))
-            .unwrap_or(true);
-        if !is_macro_callsite {
-            self.resolver.lint_buffer().buffer_lint_with_diagnostic(
-                MISSING_ABI,
-                id,
-                span,
-                "extern declarations without an explicit ABI are deprecated",
-                BuiltinLintDiagnostics::MissingAbi(span, default),
-            )
-        }
-    }
 }
 
 fn body_ids(bodies: &BTreeMap<hir::BodyId, hir::Body<'_>>) -> Vec<hir::BodyId> {