Test validity of pattern types

compiler/rustc_const_eval/src/interpret/validity.rs

@@ -1240,6 +1240,17 @@ impl<'rt, 'tcx, M: Machine<'tcx>> ValueVisitor<'tcx, M> for ValidityVisitor<'rt,
                     self.visit_field(val, 0, &self.ecx.project_index(val, 0)?)?;
                 }
             }
+            ty::Pat(base, pat) => {
+                // First check that the base type is valid
+                self.visit_value(&val.transmute(self.ecx.layout_of(*base)?, self.ecx)?)?;
+                // When you extend this match, make sure to also add tests to
+                // tests/ui/type/pattern_types/validity.rs((
+                match **pat {
+                    // Range patterns are precisely reflected into `valid_range` and thus
+                    // handled fully by `visit_scalar` (called below).
+                    ty::PatternKind::Range { .. } => {},
+                }
+            }
             _ => {
                 // default handler
                 try_validation!(

compiler/rustc_hir_analysis/messages.ftl

@@ -234,6 +234,9 @@ hir_analysis_inherent_ty_outside_relevant = cannot define inherent `impl` for a
     .help = consider moving this inherent impl into the crate defining the type if possible
     .span_help = alternatively add `#[rustc_allow_incoherent_impl]` to the relevant impl items
 
+hir_analysis_invalid_base_type = `{$ty}` is not a valid base type for range patterns
+    .note = range patterns only support integers
+
 hir_analysis_invalid_generic_receiver_ty = invalid generic `self` parameter type: `{$receiver_ty}`
     .note = type of `self` must not be a method generic parameter type
 
@@ -438,7 +441,6 @@ hir_analysis_pattern_type_wild_pat = wildcard patterns are not permitted for pat
     .label = this type is the same as the inner type without a pattern
 hir_analysis_placeholder_not_allowed_item_signatures = the placeholder `_` is not allowed within types on item signatures for {$kind}
     .label = not allowed in type signatures
-
 hir_analysis_precise_capture_self_alias = `Self` can't be captured in `use<...>` precise captures list, since it is an alias
     .label = `Self` is not a generic argument, but an alias to the type of the {$what}
 

compiler/rustc_hir_analysis/src/errors/pattern_types.rs

@@ -1,4 +1,5 @@
 use rustc_macros::Diagnostic;
+use rustc_middle::ty::Ty;
 use rustc_span::Span;
 
 #[derive(Diagnostic)]
@@ -7,3 +8,14 @@ pub(crate) struct WildPatTy {
     #[primary_span]
     pub span: Span,
 }
+
+#[derive(Diagnostic)]
+#[diag(hir_analysis_invalid_base_type)]
+pub(crate) struct InvalidBaseType<'tcx> {
+    pub ty: Ty<'tcx>,
+    #[primary_span]
+    pub ty_span: Span,
+    pub pat: &'static str,
+    #[note]
+    pub pat_span: Span,
+}

compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

@@ -53,7 +53,7 @@ use tracing::{debug, instrument};
 
 use crate::bounds::Bounds;
 use crate::check::check_abi_fn_ptr;
-use crate::errors::{AmbiguousLifetimeBound, BadReturnTypeNotation, WildPatTy};
+use crate::errors::{AmbiguousLifetimeBound, BadReturnTypeNotation, InvalidBaseType, WildPatTy};
 use crate::hir_ty_lowering::errors::{GenericsArgsErrExtend, prohibit_assoc_item_constraint};
 use crate::hir_ty_lowering::generics::{check_generic_arg_count, lower_generic_args};
 use crate::middle::resolve_bound_vars as rbv;
@@ -2432,13 +2432,26 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 self.ty_infer(None, hir_ty.span)
             }
             hir::TyKind::Pat(ty, pat) => {
+                let ty_span = ty.span;
                 let ty = self.lower_ty(ty);
                 let pat_ty = match pat.kind {
                     hir::PatKind::Wild => {
                         let err = self.dcx().emit_err(WildPatTy { span: pat.span });
                         Ty::new_error(tcx, err)
                     }
                     hir::PatKind::Range(start, end, include_end) => {
+                        let ty = match ty.kind() {
+                            ty::Int(_) | ty::Uint(_) | ty::Char => ty,
+                            _ => Ty::new_error(
+                                tcx,
+                                self.dcx().emit_err(InvalidBaseType {
+                                    ty,
+                                    pat: "range",
+                                    ty_span,
+                                    pat_span: pat.span,
+                                }),
+                            ),
+                        };
                         let expr_to_const = |expr: &'tcx hir::PatExpr<'tcx>| -> ty::Const<'tcx> {
                             let (c, c_ty) = match expr.kind {
                                 hir::PatExprKind::Lit { lit, negated } => {

tests/ui/type/pattern_types/chars.rs

@@ -0,0 +1,12 @@
+//! Check that chars can be used in ranges
+
+//@ check-pass
+
+#![feature(pattern_types)]
+#![feature(pattern_type_macro)]
+
+use std::pat::pattern_type;
+
+const LOWERCASE: pattern_type!(char is 'a'..='z') = unsafe { std::mem::transmute('b') };
+
+fn main() {}

tests/ui/type/pattern_types/nested.rs

@@ -0,0 +1,26 @@
+//! Check that pattern types can only have specific base types
+
+#![feature(pattern_types)]
+#![feature(pattern_type_macro)]
+
+use std::pat::pattern_type;
+
+// Undoing an inner pattern type's restrictions should either be forbidden,
+// or still validate correctly.
+const BAD_NESTING: pattern_type!(pattern_type!(u32 is 1..) is 0..) = todo!();
+//~^ ERROR: not a valid base type for range patterns
+
+// We want to get the most narrowest version that a pattern could be
+const BAD_NESTING2: pattern_type!(pattern_type!(i32 is 1..) is ..=-1) = todo!();
+//~^ ERROR: not a valid base type for range patterns
+
+const BAD_NESTING3: pattern_type!(pattern_type!(i32 is 1..) is ..0) = todo!();
+//~^ ERROR: not a valid base type for range patterns
+
+const BAD_NESTING4: pattern_type!(() is ..0) = todo!();
+//~^ ERROR: not a valid base type for range patterns
+
+const BAD_NESTING5: pattern_type!(f32 is 1.0 .. 2.0) = todo!();
+//~^ ERROR: not a valid base type for range patterns
+
+fn main() {}

tests/ui/type/pattern_types/nested.stderr

@@ -0,0 +1,62 @@
+error: `(u32) is 1..=` is not a valid base type for range patterns
+  --> $DIR/nested.rs:10:34
+   |
+LL | const BAD_NESTING: pattern_type!(pattern_type!(u32 is 1..) is 0..) = todo!();
+   |                                  ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: range patterns only support integers
+  --> $DIR/nested.rs:10:63
+   |
+LL | const BAD_NESTING: pattern_type!(pattern_type!(u32 is 1..) is 0..) = todo!();
+   |                                                               ^^^
+
+error: `(i32) is 1..=` is not a valid base type for range patterns
+  --> $DIR/nested.rs:14:35
+   |
+LL | const BAD_NESTING2: pattern_type!(pattern_type!(i32 is 1..) is ..=-1) = todo!();
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: range patterns only support integers
+  --> $DIR/nested.rs:14:64
+   |
+LL | const BAD_NESTING2: pattern_type!(pattern_type!(i32 is 1..) is ..=-1) = todo!();
+   |                                                                ^^^^^
+
+error: `(i32) is 1..=` is not a valid base type for range patterns
+  --> $DIR/nested.rs:17:35
+   |
+LL | const BAD_NESTING3: pattern_type!(pattern_type!(i32 is 1..) is ..0) = todo!();
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: range patterns only support integers
+  --> $DIR/nested.rs:17:64
+   |
+LL | const BAD_NESTING3: pattern_type!(pattern_type!(i32 is 1..) is ..0) = todo!();
+   |                                                                ^^^
+
+error: `()` is not a valid base type for range patterns
+  --> $DIR/nested.rs:20:35
+   |
+LL | const BAD_NESTING4: pattern_type!(() is ..0) = todo!();
+   |                                   ^^
+   |
+note: range patterns only support integers
+  --> $DIR/nested.rs:20:41
+   |
+LL | const BAD_NESTING4: pattern_type!(() is ..0) = todo!();
+   |                                         ^^^
+
+error: `f32` is not a valid base type for range patterns
+  --> $DIR/nested.rs:23:35
+   |
+LL | const BAD_NESTING5: pattern_type!(f32 is 1.0 .. 2.0) = todo!();
+   |                                   ^^^
+   |
+note: range patterns only support integers
+  --> $DIR/nested.rs:23:42
+   |
+LL | const BAD_NESTING5: pattern_type!(f32 is 1.0 .. 2.0) = todo!();
+   |                                          ^^^^^^^^^^
+
+error: aborting due to 5 previous errors
+

tests/ui/type/pattern_types/pattern_type_mismatch.rs

@@ -0,0 +1,20 @@
+//! Check that pattern types patterns must be of the type of the base type
+
+//@ known-bug: unknown
+//@ failure-status: 101
+//@ normalize-stderr: "note: .*\n\n" -> ""
+//@ normalize-stderr: "thread 'rustc' panicked.*\n" -> ""
+//@ normalize-stderr: "(error: internal compiler error: [^:]+):\d+:\d+: " -> "$1:LL:CC: "
+//@ normalize-stderr: "(delayed at compiler/rustc_mir_transform/src/lib.rs:)\d+:\d+" -> "$1:LL:CC"
+//@ rustc-env:RUST_BACKTRACE=0
+
+#![feature(pattern_types)]
+#![feature(pattern_type_macro)]
+
+use std::pat::pattern_type;
+
+const BAD_NESTING4: pattern_type!(u8 is 'a'..='a') = todo!();
+
+const BAD_NESTING5: pattern_type!(char is 1..=1) = todo!();
+
+fn main() {}

tests/ui/type/pattern_types/pattern_type_mismatch.stderr

@@ -0,0 +1,31 @@
+error: internal compiler error: ty::ConstKind::Error constructed but no error reported
+   |
+   = error: internal compiler error: ty::ConstKind::Error constructed but no error reported
+   |
+   = note: delayed at compiler/rustc_mir_build/src/thir/constant.rs:72:21 - disabled backtrace
+   = error: internal compiler error: mir_const_qualif: MIR had errors
+  --> $DIR/pattern_type_mismatch.rs:16:1
+   |
+LL | const BAD_NESTING4: pattern_type!(u8 is 'a'..='a') = todo!();
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: delayed at compiler/rustc_mir_transform/src/lib.rs::LL:CC - disabled backtrace
+  --> $DIR/pattern_type_mismatch.rs:16:1
+   |
+LL | const BAD_NESTING4: pattern_type!(u8 is 'a'..='a') = todo!();
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: internal compiler error: mir_const_qualif: MIR had errors
+  --> $DIR/pattern_type_mismatch.rs:18:1
+   |
+LL | const BAD_NESTING5: pattern_type!(char is 1..=1) = todo!();
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: delayed at compiler/rustc_mir_transform/src/lib.rs::LL:CC - disabled backtrace
+  --> $DIR/pattern_type_mismatch.rs:18:1
+   |
+LL | const BAD_NESTING5: pattern_type!(char is 1..=1) = todo!();
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+query stack during panic:
+end of query stack

tests/ui/type/pattern_types/reverse_range.rs

@@ -0,0 +1,14 @@
+//! Check that the range start must be smaller than the range end
+//@ known-bug: unknown
+//@ failure-status: 101
+//@ normalize-stderr: "note: .*\n\n" -> ""
+//@ normalize-stderr: "thread 'rustc' panicked.*\n" -> ""
+//@ normalize-stderr: "(error: internal compiler error: [^:]+):\d+:\d+: " -> "$1:LL:CC: "
+//@ rustc-env:RUST_BACKTRACE=0
+
+#![feature(pattern_types)]
+#![feature(pattern_type_macro)]
+
+use std::pat::pattern_type;
+
+const NONE: pattern_type!(u8 is 1..0) = unsafe { std::mem::transmute(3_u8) };

tests/ui/type/pattern_types/reverse_range.stderr

@@ -0,0 +1,17 @@
+error[E0601]: `main` function not found in crate `reverse_range`
+  --> $DIR/reverse_range.rs:14:78
+   |
+LL | const NONE: pattern_type!(u8 is 1..0) = unsafe { std::mem::transmute(3_u8) };
+   |                                                                              ^ consider adding a `main` function to `$DIR/reverse_range.rs`
+
+
+assertion failed: end <= max_value
+error: the compiler unexpectedly panicked. this is a bug.
+
+query stack during panic:
+#0 [eval_to_allocation_raw] const-evaluating + checking `NONE`
+#1 [eval_to_const_value_raw] simplifying constant for the type system `NONE`
+... and 1 other queries... use `env RUST_BACKTRACE=1` to see the full query stack
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0601`.

tests/ui/type/pattern_types/validity.rs

@@ -0,0 +1,37 @@
+//! Check that pattern types have their validity checked
+
+#![feature(pattern_types)]
+#![feature(pattern_type_macro)]
+
+use std::pat::pattern_type;
+
+const BAD: pattern_type!(u32 is 1..) = unsafe { std::mem::transmute(0) };
+//~^ ERROR: it is undefined behavior to use this value
+
+const BAD_UNINIT: pattern_type!(u32 is 1..) =
+    //~^ ERROR: evaluation of constant value failed
+    unsafe { std::mem::transmute(std::mem::MaybeUninit::<u32>::uninit()) };
+
+const BAD_PTR: pattern_type!(usize is 1..) = unsafe { std::mem::transmute(&42) };
+//~^ ERROR: evaluation of constant value failed
+
+const BAD_AGGREGATE: (pattern_type!(u32 is 1..), u32) = (unsafe { std::mem::transmute(0) }, 0);
+//~^ ERROR: it is undefined behavior to use this value
+
+struct Foo(Bar);
+struct Bar(pattern_type!(u32 is 1..));
+
+const BAD_FOO: Foo = Foo(Bar(unsafe { std::mem::transmute(0) }));
+//~^ ERROR: it is undefined behavior to use this value
+
+const CHAR_UNINIT: pattern_type!(char is 'A'..'Z') =
+    //~^ ERROR: evaluation of constant value failed
+    unsafe { std::mem::transmute(std::mem::MaybeUninit::<u32>::uninit()) };
+
+const CHAR_OOB_PAT: pattern_type!(char is 'A'..'Z') = unsafe { std::mem::transmute('a') };
+//~^ ERROR: it is undefined behavior to use this value
+
+const CHAR_OOB: pattern_type!(char is 'A'..'Z') = unsafe { std::mem::transmute(u32::MAX) };
+//~^ ERROR: it is undefined behavior to use this value
+
+fn main() {}

tests/ui/type/pattern_types/validity.stderr

@@ -0,0 +1,79 @@
+error[E0080]: it is undefined behavior to use this value
+  --> $DIR/validity.rs:8:1
+   |
+LL | const BAD: pattern_type!(u32 is 1..) = unsafe { std::mem::transmute(0) };
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered 0, but expected something greater or equal to 1
+   |
+   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
+   = note: the raw bytes of the constant (size: 4, align: 4) {
+               00 00 00 00                                     │ ....
+           }
+
+error[E0080]: evaluation of constant value failed
+  --> $DIR/validity.rs:11:1
+   |
+LL | const BAD_UNINIT: pattern_type!(u32 is 1..) =
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
+
+error[E0080]: evaluation of constant value failed
+  --> $DIR/validity.rs:15:1
+   |
+LL | const BAD_PTR: pattern_type!(usize is 1..) = unsafe { std::mem::transmute(&42) };
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into integer
+   |
+   = help: this code performed an operation that depends on the underlying bytes representing a pointer
+   = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
+
+error[E0080]: it is undefined behavior to use this value
+  --> $DIR/validity.rs:18:1
+   |
+LL | const BAD_AGGREGATE: (pattern_type!(u32 is 1..), u32) = (unsafe { std::mem::transmute(0) }, 0);
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .0: encountered 0, but expected something greater or equal to 1
+   |
+   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
+   = note: the raw bytes of the constant (size: 8, align: 4) {
+               00 00 00 00 00 00 00 00                         │ ........
+           }
+
+error[E0080]: it is undefined behavior to use this value
+  --> $DIR/validity.rs:24:1
+   |
+LL | const BAD_FOO: Foo = Foo(Bar(unsafe { std::mem::transmute(0) }));
+   | ^^^^^^^^^^^^^^^^^^ constructing invalid value at .0.0: encountered 0, but expected something greater or equal to 1
+   |
+   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
+   = note: the raw bytes of the constant (size: 4, align: 4) {
+               00 00 00 00                                     │ ....
+           }
+
+error[E0080]: evaluation of constant value failed
+  --> $DIR/validity.rs:27:1
+   |
+LL | const CHAR_UNINIT: pattern_type!(char is 'A'..'Z') =
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
+
+error[E0080]: it is undefined behavior to use this value
+  --> $DIR/validity.rs:31:1
+   |
+LL | const CHAR_OOB_PAT: pattern_type!(char is 'A'..'Z') = unsafe { std::mem::transmute('a') };
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered 97, but expected something in the range 65..=89
+   |
+   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
+   = note: the raw bytes of the constant (size: 4, align: 4) {
+               61 00 00 00                                     │ a...
+           }
+
+error[E0080]: it is undefined behavior to use this value
+  --> $DIR/validity.rs:34:1
+   |
+LL | const CHAR_OOB: pattern_type!(char is 'A'..'Z') = unsafe { std::mem::transmute(u32::MAX) };
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered 0xffffffff, but expected a valid unicode scalar value (in `0..=0x10FFFF` but not in `0xD800..=0xDFFF`)
+   |
+   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
+   = note: the raw bytes of the constant (size: 4, align: 4) {
+               ff ff ff ff                                     │ ....
+           }
+
+error: aborting due to 8 previous errors
+
+For more information about this error, try `rustc --explain E0080`.