Add pattern types to the compiler

Author: oli-obk

compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs

@@ -194,6 +194,15 @@ fn push_debuginfo_type_name<'tcx>(
                 }
             }
         }
+        ty::Pat(inner_type, pat) => {
+            if cpp_like_debuginfo {
+                output.push_str("pat$<");
+                push_debuginfo_type_name(tcx, inner_type, true, output, visited);
+                write!(output, ",{:?}>", pat).unwrap();
+            } else {
+                write!(output, "{:?}", t).unwrap();
+            }
+        }
         ty::Slice(inner_type) => {
             if cpp_like_debuginfo {
                 output.push_str("slice2$<");

compiler/rustc_const_eval/src/const_eval/valtrees.rs

@@ -96,6 +96,8 @@ pub(crate) fn const_to_valtree_inner<'tcx>(
             Ok(ty::ValTree::Leaf(val.assert_int()))
         }
 
+        ty::Pat(..) => const_to_valtree_inner(ecx, &ecx.mplace_field(&place, 0).unwrap(), num_nodes),
+
         // Raw pointers are not allowed in type level constants, as we cannot properly test them for
         // equality at compile-time (see `ptr_guaranteed_cmp`).
         // Technically we could allow function pointers (represented as `ty::Instance`), but this is not guaranteed to
@@ -265,7 +267,7 @@ pub fn valtree_to_const_value<'tcx>(
     let (param_env, ty) = param_env_ty.into_parts();
     let mut ecx = mk_eval_cx(tcx, DUMMY_SP, param_env, false);
 
-    match ty.kind() {
+    match *ty.kind() {
         ty::FnDef(..) => {
             assert!(valtree.unwrap_branch().is_empty());
             ConstValue::ZeroSized
@@ -276,6 +278,7 @@ pub fn valtree_to_const_value<'tcx>(
                 "ValTrees for Bool, Int, Uint, Float or Char should have the form ValTree::Leaf"
             ),
         },
+        ty::Pat(ty, _) => valtree_to_const_value(tcx, param_env.and(ty), valtree),
         ty::Ref(_, _, _) | ty::Tuple(_) | ty::Array(_, _) | ty::Adt(..) => {
             let mut place = match ty.kind() {
                 ty::Ref(_, inner_ty, _) => {

compiler/rustc_const_eval/src/interpret/intrinsics.rs

@@ -83,6 +83,9 @@ pub(crate) fn eval_nullary_intrinsic<'tcx>(
             ty::Alias(..) | ty::Param(_) | ty::Placeholder(_) | ty::Infer(_) => {
                 throw_inval!(TooGeneric)
             }
+            ty::Pat(..) => {
+                unimplemented!("pattern types need to calculate pattern from their pattern")
+            }
             ty::Bound(_, _) => bug!("bound ty during ctfe"),
             ty::Bool
             | ty::Char

compiler/rustc_const_eval/src/interpret/validity.rs

@@ -584,6 +584,7 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
                 // Nothing to check.
                 Ok(true)
             }
+            ty::Pat(..) => unimplemented!(),
             // The above should be all the primitive types. The rest is compound, we
             // check them by visiting their fields/variants.
             ty::Adt(..)

compiler/rustc_const_eval/src/util/type_name.rs

@@ -40,6 +40,7 @@ impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> {
             | ty::Uint(_)
             | ty::Float(_)
             | ty::Str
+            | ty::Pat(_, _)
             | ty::Array(_, _)
             | ty::Slice(_)
             | ty::RawPtr(_)

compiler/rustc_error_messages/locales/en-US/lint.ftl

@@ -237,6 +237,9 @@ lint_improper_ctypes_128bit = 128-bit integers don't currently have a known stab
 lint_improper_ctypes_char_reason = the `char` type has no C equivalent
 lint_improper_ctypes_char_help = consider using `u32` or `libc::wchar_t` instead
 
+lint_improper_ctypes_pat_reason = pattern types have no C equivalent
+lint_improper_ctypes_pat_help = consider using the patterned type instead
+
 lint_improper_ctypes_non_exhaustive = this enum is non-exhaustive
 lint_improper_ctypes_non_exhaustive_variant = this enum has non-exhaustive variants
 

compiler/rustc_hir_analysis/src/coherence/inherent_impls.rs

@@ -208,6 +208,9 @@ impl<'tcx> InherentCollect<'tcx> {
                 .note("define and implement a new trait or type instead")
                 .emit();
             }
+            ty::Pat(..) => {
+                self.tcx.sess.span_err(ty.span, "cannot define inherent `impl` for pattern types");
+            }
             ty::Bool
             | ty::Char
             | ty::Int(_)

compiler/rustc_hir_analysis/src/variance/constraints.rs

@@ -231,6 +231,16 @@ impl<'a, 'tcx> ConstraintContext<'a, 'tcx> {
                 self.add_constraints_from_ty(current, typ, variance);
             }
 
+            ty::Pat(typ, pat) => {
+                match *pat {
+                    ty::PatternKind::Range { start, end } => {
+                        self.add_constraints_from_const(current, start, variance);
+                        self.add_constraints_from_const(current, end, variance);
+                    }
+                }
+                self.add_constraints_from_ty(current, typ, variance);
+            }
+
             ty::Slice(typ) => {
                 self.add_constraints_from_ty(current, typ, variance);
             }

compiler/rustc_hir_typeck/src/cast.rs

@@ -132,6 +132,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             | ty::GeneratorWitness(..)
             | ty::RawPtr(_)
             | ty::Ref(..)
+            | ty::Pat(..)
             | ty::FnDef(..)
             | ty::FnPtr(..)
             | ty::Closure(..)

compiler/rustc_infer/src/infer/canonical/canonicalizer.rs

@@ -454,6 +454,7 @@ impl<'cx, 'tcx> TypeFolder<'tcx> for Canonicalizer<'cx, 'tcx> {
             | ty::Tuple(..)
             | ty::Alias(..)
             | ty::Foreign(..)
+            | ty::Pat(..)
             | ty::Param(..) => {
                 if t.flags().intersects(self.needs_canonical_flags) {
                     t.super_fold_with(self)