get rid of min_const_fn references in library/ and rustdoc

Author: RalfJung

library/alloc/src/raw_vec.rs

@@ -53,17 +53,11 @@ pub struct RawVec<T, A: Allocator = Global> {
 }
 
 impl<T> RawVec<T, Global> {
-    /// HACK(Centril): This exists because `#[unstable]` `const fn`s needn't conform
-    /// to `min_const_fn` and so they cannot be called in `min_const_fn`s either.
+    /// HACK(Centril): This exists because stable `const fn` can only call stable `const fn`, so
+    /// they cannot call `Self::new()`.
     ///
-    /// If you change `RawVec<T>::new` or dependencies, please take care to not
-    /// introduce anything that would truly violate `min_const_fn`.
-    ///
-    /// NOTE: We could avoid this hack and check conformance with some
-    /// `#[rustc_force_min_const_fn]` attribute which requires conformance
-    /// with `min_const_fn` but does not necessarily allow calling it in
-    /// `stable(...) const fn` / user code not enabling `foo` when
-    /// `#[rustc_const_unstable(feature = "foo", issue = "01234")]` is present.
+    /// If you change `RawVec<T>::new` or dependencies, please take care to not introduce anything
+    /// that would truly const-call something unstable.
     pub const NEW: Self = Self::new();
 
     /// Creates the biggest possible `RawVec` (on the system heap)

src/librustdoc/clean/inline.rs

@@ -10,7 +10,6 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::Mutability;
 use rustc_metadata::creader::LoadedMacro;
 use rustc_middle::ty::{self, TyCtxt};
-use rustc_mir::const_eval::is_min_const_fn;
 use rustc_span::hygiene::MacroKind;
 use rustc_span::symbol::{kw, sym, Symbol};
 use rustc_span::Span;
@@ -210,7 +209,7 @@ fn build_external_function(cx: &mut DocContext<'_>, did: DefId) -> clean::Functi
     let sig = cx.tcx.fn_sig(did);
 
     let constness =
-        if is_min_const_fn(cx.tcx, did) { hir::Constness::Const } else { hir::Constness::NotConst };
+        if cx.tcx.is_const_fn_raw(did) { hir::Constness::Const } else { hir::Constness::NotConst };
     let asyncness = cx.tcx.asyncness(did);
     let predicates = cx.tcx.predicates_of(did);
     let (generics, decl) = clean::enter_impl_trait(cx, |cx| {

src/librustdoc/clean/mod.rs

@@ -22,7 +22,7 @@ use rustc_middle::middle::resolve_lifetime as rl;
 use rustc_middle::ty::fold::TypeFolder;
 use rustc_middle::ty::subst::{InternalSubsts, Subst};
 use rustc_middle::ty::{self, AdtKind, Lift, Ty, TyCtxt};
-use rustc_mir::const_eval::{is_const_fn, is_min_const_fn, is_unstable_const_fn};
+use rustc_mir::const_eval::{is_const_fn, is_unstable_const_fn};
 use rustc_span::hygiene::{AstPass, MacroKind};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{self, ExpnKind};
@@ -1048,7 +1048,7 @@ impl Clean<Item> for ty::AssocItem {
                     ty::TraitContainer(_) => self.defaultness.has_value(),
                 };
                 if provided {
-                    let constness = if is_min_const_fn(tcx, self.def_id) {
+                    let constness = if tcx.is_const_fn_raw(self.def_id) {
                         hir::Constness::Const
                     } else {
                         hir::Constness::NotConst