Add AltPattern HIR node

Example:
	match x {
	    0 | 1 => true,
	    _ => false
	}

gcc/rust/ChangeLog:

	* backend/rust-compile-fnparam.h:
	(CompileFnParam::visit): Add AltPattern visitor.
	* backend/rust-compile-pattern.h:
	(CompilePatternCaseLabelExpr::visit): Add AltPattern visitor.
	(CompilePatternBindings::visit): Add AltPattern visitor.
	(CompilePatternLet::visit): Add AltPattern visitor.
	* backend/rust-compile-resolve-path.h:
	(ResolvePathRef::visit): Add AltPattern visitor.
	* backend/rust-compile-var-decl.h:
	(CompileVarDecl::visit): Add AltPattern visitor.
	* checks/errors/rust-const-checker.cc
	(ConstChecker::visit): Add AltPattern visitor.
	* checks/errors/rust-const-checker.h:
	(ConstChecker::visit): Add AltPattern visitor.
	* checks/errors/rust-unsafe-checker.cc
	(UnsafeChecker::visit): Add AltPattern visitor.
	* checks/errors/rust-unsafe-checker.h:
	(UnsafeChecker::visit): Add AltPattern visitor.
	* hir/rust-hir-dump.cc
	(Dump::visit): Add AltPattern visitor.
	* hir/rust-hir-dump.h:
	(Dump::visit): Add AltPattern visitor.
	* hir/tree/rust-hir-full-decls.h
	(class AltPattern): Add forward declaration.
	* hir/tree/rust-hir-pattern.h
	(class AltPattern): New class.
	* hir/tree/rust-hir-visitor.h:
	(HIRFullVisitor::visit): Add AltPattern visitor.
	(HIRFullVisitorBase::visit): Add AltPattern visitor.
	(HIRPatternVisitor::visit): Add AltPattern visitor.
	* hir/tree/rust-hir.h:
	(Pattern::PatternType::ALT): New enumerator.
	* typecheck/rust-hir-type-check-pattern.cc
	(TypeCheckPattern::visit): Add AltPattern visitor.
	* typecheck/rust-hir-type-check-pattern.h:
	(TypeCheckPattern::visit): Add AltPattern visitor.

Signed-off-by: Owen Avery <powerboat9.gamer@gmail.com>

16 files changed, 117 insertions, 0 deletions

diff --git a/gcc/rust/backend/rust-compile-fnparam.h b/gcc/rust/backend/rust-compile-fnparam.h
index 10e8b67..c5b08e3a 100644
--- a/gcc/rust/backend/rust-compile-fnparam.h
+++ b/gcc/rust/backend/rust-compile-fnparam.h
@@ -39,6 +39,7 @@ public:
   void visit (HIR::TupleStructPattern &) override;
 
   // Empty visit for unused Pattern HIR nodes.
+  void visit (HIR::AltPattern &) override {}
   void visit (HIR::LiteralPattern &) override {}
   void visit (HIR::PathInExpression &) override {}
   void visit (HIR::QualifiedPathInExpression &) override {}
diff --git a/gcc/rust/backend/rust-compile-pattern.h b/gcc/rust/backend/rust-compile-pattern.h
index 8f44b7b..93faeeae 100644
--- a/gcc/rust/backend/rust-compile-pattern.h
+++ b/gcc/rust/backend/rust-compile-pattern.h
@@ -39,6 +39,13 @@ public:
   void visit (HIR::WildcardPattern &pattern) override;
   void visit (HIR::RangePattern &pattern) override;
 
+  // unsupported
+  void visit (HIR::AltPattern &pattern) override
+  {
+    rust_sorry_at (pattern.get_locus (),
+		   "alternate pattern case labels not supported");
+  }
+
   // Empty visit for unused Pattern HIR nodes.
   void visit (HIR::IdentifierPattern &) override {}
   void visit (HIR::LiteralPattern &) override;
@@ -70,6 +77,13 @@ public:
   void visit (HIR::StructPattern &pattern) override;
   void visit (HIR::TupleStructPattern &pattern) override;
 
+  // unsupported
+  void visit (HIR::AltPattern &pattern) override
+  {
+    rust_sorry_at (pattern.get_locus (),
+		   "alternate pattern bindings not supported");
+  }
+
   // Empty visit for unused Pattern HIR nodes.
   void visit (HIR::IdentifierPattern &) override {}
   void visit (HIR::LiteralPattern &) override {}
@@ -104,6 +118,12 @@ public:
   void visit (HIR::TuplePattern &) override;
 
   // check for unimplemented Pattern HIR nodes.
+  void visit (HIR::AltPattern &pattern) override
+  {
+    rust_sorry_at (pattern.get_locus (),
+		   "alternate pattern let statements not supported");
+  }
+
   void visit (HIR::LiteralPattern &pattern) override
   {
     rust_sorry_at (pattern.get_locus (),
diff --git a/gcc/rust/backend/rust-compile-resolve-path.h b/gcc/rust/backend/rust-compile-resolve-path.h
index 6aec7be..ad7a67f 100644
--- a/gcc/rust/backend/rust-compile-resolve-path.h
+++ b/gcc/rust/backend/rust-compile-resolve-path.h
@@ -50,6 +50,7 @@ public:
   void visit (HIR::RangePattern &) override {}
   void visit (HIR::ReferencePattern &) override {}
   void visit (HIR::SlicePattern &) override {}
+  void visit (HIR::AltPattern &) override {}
   void visit (HIR::StructPattern &) override {}
   void visit (HIR::TuplePattern &) override {}
   void visit (HIR::TupleStructPattern &) override {}
diff --git a/gcc/rust/backend/rust-compile-var-decl.h b/gcc/rust/backend/rust-compile-var-decl.h
index 13b429d..bc83816 100644
--- a/gcc/rust/backend/rust-compile-var-decl.h
+++ b/gcc/rust/backend/rust-compile-var-decl.h
@@ -54,6 +54,7 @@ public:
   }
 
   // Empty visit for unused Pattern HIR nodes.
+  void visit (HIR::AltPattern &) override {}
   void visit (HIR::LiteralPattern &) override {}
   void visit (HIR::PathInExpression &) override {}
   void visit (HIR::QualifiedPathInExpression &) override {}
diff --git a/gcc/rust/checks/errors/rust-const-checker.cc b/gcc/rust/checks/errors/rust-const-checker.cc
index 3752cf3..d0ca5cf 100644
--- a/gcc/rust/checks/errors/rust-const-checker.cc
+++ b/gcc/rust/checks/errors/rust-const-checker.cc
@@ -839,6 +839,10 @@ ConstChecker::visit (SlicePattern &)
 {}
 
 void
+ConstChecker::visit (AltPattern &)
+{}
+
+void
 ConstChecker::visit (EmptyStmt &)
 {}
 
diff --git a/gcc/rust/checks/errors/rust-const-checker.h b/gcc/rust/checks/errors/rust-const-checker.h
index e040236..2183992 100644
--- a/gcc/rust/checks/errors/rust-const-checker.h
+++ b/gcc/rust/checks/errors/rust-const-checker.h
@@ -187,6 +187,7 @@ private:
   virtual void visit (TuplePatternItemsRanged &tuple_items) override;
   virtual void visit (TuplePattern &pattern) override;
   virtual void visit (SlicePattern &pattern) override;
+  virtual void visit (AltPattern &pattern) override;
   virtual void visit (EmptyStmt &stmt) override;
   virtual void visit (LetStmt &stmt) override;
   virtual void visit (ExprStmtWithoutBlock &stmt) override;
diff --git a/gcc/rust/checks/errors/rust-unsafe-checker.cc b/gcc/rust/checks/errors/rust-unsafe-checker.cc
index ff7a0b3..be85c90 100644
--- a/gcc/rust/checks/errors/rust-unsafe-checker.cc
+++ b/gcc/rust/checks/errors/rust-unsafe-checker.cc
@@ -906,6 +906,10 @@ UnsafeChecker::visit (SlicePattern &)
 {}
 
 void
+UnsafeChecker::visit (AltPattern &)
+{}
+
+void
 UnsafeChecker::visit (EmptyStmt &)
 {}
 
diff --git a/gcc/rust/checks/errors/rust-unsafe-checker.h b/gcc/rust/checks/errors/rust-unsafe-checker.h
index ce270c0..2e6719a 100644
--- a/gcc/rust/checks/errors/rust-unsafe-checker.h
+++ b/gcc/rust/checks/errors/rust-unsafe-checker.h
@@ -169,6 +169,7 @@ private:
   virtual void visit (TuplePatternItemsRanged &tuple_items) override;
   virtual void visit (TuplePattern &pattern) override;
   virtual void visit (SlicePattern &pattern) override;
+  virtual void visit (AltPattern &pattern) override;
   virtual void visit (EmptyStmt &stmt) override;
   virtual void visit (LetStmt &stmt) override;
   virtual void visit (ExprStmtWithoutBlock &stmt) override;
diff --git a/gcc/rust/hir/rust-hir-dump.cc b/gcc/rust/hir/rust-hir-dump.cc
index d6b458b..9975a1e 100644
--- a/gcc/rust/hir/rust-hir-dump.cc
+++ b/gcc/rust/hir/rust-hir-dump.cc
@@ -580,6 +580,9 @@ Dump::visit (TuplePattern &)
 void
 Dump::visit (SlicePattern &)
 {}
+void
+Dump::visit (AltPattern &)
+{}
 
 void
 Dump::visit (EmptyStmt &)
diff --git a/gcc/rust/hir/rust-hir-dump.h b/gcc/rust/hir/rust-hir-dump.h
index b66e6b1..c1ef9849b 100644
--- a/gcc/rust/hir/rust-hir-dump.h
+++ b/gcc/rust/hir/rust-hir-dump.h
@@ -164,6 +164,7 @@ private:
   virtual void visit (TuplePatternItemsRanged &) override;
   virtual void visit (TuplePattern &) override;
   virtual void visit (SlicePattern &) override;
+  virtual void visit (AltPattern &) override;
 
   virtual void visit (EmptyStmt &) override;
   virtual void visit (LetStmt &) override;
diff --git a/gcc/rust/hir/tree/rust-hir-full-decls.h b/gcc/rust/hir/tree/rust-hir-full-decls.h
index 30adda6..d486d91 100644
--- a/gcc/rust/hir/tree/rust-hir-full-decls.h
+++ b/gcc/rust/hir/tree/rust-hir-full-decls.h
@@ -207,6 +207,7 @@ class TuplePatternItemsMultiple;
 class TuplePatternItemsRanged;
 class TuplePattern;
 class SlicePattern;
+class AltPattern;
 
 // rust-type.h
 class TraitBound;
diff --git a/gcc/rust/hir/tree/rust-hir-pattern.h b/gcc/rust/hir/tree/rust-hir-pattern.h
index 47a38cc..69faed1 100644
--- a/gcc/rust/hir/tree/rust-hir-pattern.h
+++ b/gcc/rust/hir/tree/rust-hir-pattern.h
@@ -1300,6 +1300,73 @@ protected:
   }
 };
 
+// HIR node for alternative patterns
+class AltPattern : public Pattern
+{
+  std::vector<std::unique_ptr<Pattern>> alts;
+  Location locus;
+  Analysis::NodeMapping mappings;
+
+public:
+public:
+  std::string as_string () const override;
+
+  AltPattern (Analysis::NodeMapping mappings,
+	      std::vector<std::unique_ptr<Pattern>> alts, Location locus)
+    : alts (std::move (alts)), locus (locus), mappings (mappings)
+  {}
+
+  // Copy constructor with vector clone
+  AltPattern (AltPattern const &other)
+    : locus (other.locus), mappings (other.mappings)
+  {
+    alts.reserve (other.alts.size ());
+    for (const auto &e : other.alts)
+      alts.push_back (e->clone_pattern ());
+  }
+
+  // Overloaded assignment operator to vector clone
+  AltPattern &operator= (AltPattern const &other)
+  {
+    locus = other.locus;
+    mappings = other.mappings;
+
+    alts.clear ();
+    alts.reserve (other.alts.size ());
+    for (const auto &e : other.alts)
+      alts.push_back (e->clone_pattern ());
+
+    return *this;
+  }
+
+  // move constructors
+  AltPattern (AltPattern &&other) = default;
+  AltPattern &operator= (AltPattern &&other) = default;
+
+  Location get_locus () const override { return locus; }
+
+  void accept_vis (HIRFullVisitor &vis) override;
+  void accept_vis (HIRPatternVisitor &vis) override;
+
+  Analysis::NodeMapping get_pattern_mappings () const override final
+  {
+    return mappings;
+  }
+
+  PatternType get_pattern_type () const override final
+  {
+    return PatternType::ALT;
+  }
+
+protected:
+  /* Use covariance to implement clone function as returning this object rather
+   * than base */
+  AltPattern *clone_pattern_impl () const override
+  {
+    return new AltPattern (*this);
+  }
+};
+
 // Moved definition to rust-path.h
 class PathPattern;
 
diff --git a/gcc/rust/hir/tree/rust-hir-visitor.h b/gcc/rust/hir/tree/rust-hir-visitor.h
index a635f90..fa6f592 100644
--- a/gcc/rust/hir/tree/rust-hir-visitor.h
+++ b/gcc/rust/hir/tree/rust-hir-visitor.h
@@ -139,6 +139,7 @@ public:
   virtual void visit (TuplePatternItemsRanged &tuple_items) = 0;
   virtual void visit (TuplePattern &pattern) = 0;
   virtual void visit (SlicePattern &pattern) = 0;
+  virtual void visit (AltPattern &pattern) = 0;
   virtual void visit (EmptyStmt &stmt) = 0;
   virtual void visit (LetStmt &stmt) = 0;
   virtual void visit (ExprStmtWithoutBlock &stmt) = 0;
@@ -290,6 +291,7 @@ public:
   virtual void visit (TuplePatternItemsRanged &) override {}
   virtual void visit (TuplePattern &) override {}
   virtual void visit (SlicePattern &) override {}
+  virtual void visit (AltPattern &) override {}
 
   virtual void visit (EmptyStmt &) override {}
   virtual void visit (LetStmt &) override {}
@@ -475,6 +477,7 @@ public:
   virtual void visit (RangePattern &) = 0;
   virtual void visit (ReferencePattern &) = 0;
   virtual void visit (SlicePattern &) = 0;
+  virtual void visit (AltPattern &) = 0;
   virtual void visit (StructPattern &) = 0;
   virtual void visit (TuplePattern &) = 0;
   virtual void visit (TupleStructPattern &) = 0;
diff --git a/gcc/rust/hir/tree/rust-hir.h b/gcc/rust/hir/tree/rust-hir.h
index 28f1f21..6ed7442 100644
--- a/gcc/rust/hir/tree/rust-hir.h
+++ b/gcc/rust/hir/tree/rust-hir.h
@@ -384,6 +384,7 @@ public:
     TUPLE,
     GROUPED,
     SLICE,
+    ALT
   };
 
   BaseKind get_hir_kind () override final { return PATTERN; }
diff --git a/gcc/rust/typecheck/rust-hir-type-check-pattern.cc b/gcc/rust/typecheck/rust-hir-type-check-pattern.cc
index b7412bc..3dca07b 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-pattern.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check-pattern.cc
@@ -437,5 +437,12 @@ TypeCheckPattern::emit_pattern_size_error (const HIR::Pattern &pattern,
 		 got_field_count == 1 ? "element" : "elements");
 }
 
+void
+TypeCheckPattern::visit (HIR::AltPattern &pattern)
+{
+  rust_sorry_at (pattern.get_locus (),
+		 "type checking alternate patterns not supported");
+}
+
 } // namespace Resolver
 } // namespace Rust
diff --git a/gcc/rust/typecheck/rust-hir-type-check-pattern.h b/gcc/rust/typecheck/rust-hir-type-check-pattern.h
index a4fbf88..3b392b5 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-pattern.h
+++ b/gcc/rust/typecheck/rust-hir-type-check-pattern.h
@@ -42,6 +42,7 @@ public:
   void visit (HIR::QualifiedPathInExpression &pattern) override;
   void visit (HIR::ReferencePattern &pattern) override;
   void visit (HIR::SlicePattern &pattern) override;
+  void visit (HIR::AltPattern &pattern) override;
 
 private:
   TypeCheckPattern (TyTy::BaseType *parent);