Auto merge of rust-lang#114134 - fee1-dead-contrib:rm-constness-from-…

…param-env, r=oli-obk

Remove `constness` from `ParamEnv`

This should be replaced by keyword generics/effects. cc rust-lang#110395

r? `@oli-obk`

clippy_lints/src/derive.rs

@@ -6,7 +6,7 @@ use rustc_errors::Applicability;
 use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit::{walk_expr, walk_fn, walk_item, FnKind, Visitor};
 use rustc_hir::{
-    self as hir, BlockCheckMode, BodyId, Constness, Expr, ExprKind, FnDecl, Impl, Item, ItemKind, UnsafeSource,
+    self as hir, BlockCheckMode, BodyId, Expr, ExprKind, FnDecl, Impl, Item, ItemKind, UnsafeSource,
     Unsafety,
 };
 use rustc_lint::{LateContext, LateLintPass};
@@ -526,6 +526,5 @@ fn param_env_for_derived_eq(tcx: TyCtxt<'_>, did: DefId, eq_trait_id: DefId) ->
             }),
         )),
         Reveal::UserFacing,
-        Constness::NotConst,
     )
 }

clippy_lints/src/manual_float_methods.rs

@@ -3,7 +3,7 @@ use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::source::snippet_opt;
 use clippy_utils::{is_from_proc_macro, path_to_local};
 use rustc_errors::Applicability;
-use rustc_hir::{BinOpKind, Expr, ExprKind};
+use rustc_hir::{BinOpKind, Constness, Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass, Lint, LintContext};
 use rustc_middle::lint::in_external_macro;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
@@ -83,8 +83,10 @@ impl Variant {
 impl<'tcx> LateLintPass<'tcx> for ManualFloatMethods {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
         if !in_external_macro(cx.sess(), expr.span)
-            && (!cx.param_env.is_const() || cx.tcx.features().active(sym!(const_float_classify)))
-            && let ExprKind::Binary(kind, lhs, rhs) = expr.kind
+            && (
+                matches!(cx.tcx.constness(cx.tcx.hir().enclosing_body_owner(expr.hir_id)), Constness::NotConst) 
+                    || cx.tcx.features().active(sym!(const_float_classify))
+            ) && let ExprKind::Binary(kind, lhs, rhs) = expr.kind
             && let ExprKind::Binary(lhs_kind, lhs_lhs, lhs_rhs) = lhs.kind
             && let ExprKind::Binary(rhs_kind, rhs_lhs, rhs_rhs) = rhs.kind
             // Checking all possible scenarios using a function would be a hopeless task, as we have

clippy_utils/src/qualify_min_const_fn.rs

@@ -391,32 +391,38 @@ fn is_const_fn(tcx: TyCtxt<'_>, def_id: DefId, msrv: &Msrv) -> bool {
 
 #[expect(clippy::similar_names)] // bit too pedantic
 fn is_ty_const_destruct<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>, body: &Body<'tcx>) -> bool {
-    // Avoid selecting for simple cases, such as builtin types.
-    if ty::util::is_trivially_const_drop(ty) {
-        return true;
-    }
+    // FIXME(effects, fee1-dead) revert to const destruct once it works again
+    #[expect(unused)]
+    fn is_ty_const_destruct_unused<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>, body: &Body<'tcx>) -> bool {
+        // Avoid selecting for simple cases, such as builtin types.
+        if ty::util::is_trivially_const_drop(ty) {
+            return true;
+        }
 
-    let obligation = Obligation::new(
-        tcx,
-        ObligationCause::dummy_with_span(body.span),
-        ConstCx::new(tcx, body).param_env.with_const(),
-        TraitRef::from_lang_item(tcx, LangItem::Destruct, body.span, [ty]).with_constness(BoundConstness::ConstIfConst),
-    );
+        let obligation = Obligation::new(
+            tcx,
+            ObligationCause::dummy_with_span(body.span),
+            ConstCx::new(tcx, body).param_env,
+            TraitRef::from_lang_item(tcx, LangItem::Destruct, body.span, [ty]).with_constness(BoundConstness::ConstIfConst),
+        );
 
-    let infcx = tcx.infer_ctxt().build();
-    let mut selcx = SelectionContext::new(&infcx);
-    let Some(impl_src) = selcx.select(&obligation).ok().flatten() else {
-        return false;
-    };
+        let infcx = tcx.infer_ctxt().build();
+        let mut selcx = SelectionContext::new(&infcx);
+        let Some(impl_src) = selcx.select(&obligation).ok().flatten() else {
+            return false;
+        };
+
+        if !matches!(
+            impl_src,
+            ImplSource::Builtin(BuiltinImplSource::Misc, _) | ImplSource::Param(ty::BoundConstness::ConstIfConst, _)
+        ) {
+            return false;
+        }
 
-    if !matches!(
-        impl_src,
-        ImplSource::Builtin(BuiltinImplSource::Misc, _) | ImplSource::Param(ty::BoundConstness::ConstIfConst, _)
-    ) {
-        return false;
+        let ocx = ObligationCtxt::new(&infcx);
+        ocx.register_obligations(impl_src.nested_obligations());
+        ocx.select_all_or_error().is_empty()
     }
 
-    let ocx = ObligationCtxt::new(&infcx);
-    ocx.register_obligations(impl_src.nested_obligations());
-    ocx.select_all_or_error().is_empty()
+    !ty.needs_drop(tcx, ConstCx::new(tcx, body).param_env)    
 }

tests/ui/missing_const_for_fn/could_be_const.rs

@@ -99,4 +99,5 @@ impl const Drop for D {
 }
 
 // Lint this, since it can be dropped in const contexts
+// FIXME(effects)
 fn d(this: D) {}

tests/ui/missing_const_for_fn/could_be_const.stderr

@@ -89,11 +89,5 @@ LL | |     46
 LL | | }
    | |_^
 
-error: this could be a `const fn`
-  --> $DIR/could_be_const.rs:102:1
-   |
-LL | fn d(this: D) {}
-   | ^^^^^^^^^^^^^^^^
-
-error: aborting due to 12 previous errors
+error: aborting due to 11 previous errors