Similar to #1272, changed the type of alternative signature from generic Expression to TupleLiteral to match the grammar (#1291)

common/fuzzing/carbon.proto

@@ -300,7 +300,7 @@ message ClassDeclaration {
 
 message AlternativeSignature {
   optional string name = 1;
-  optional Expression signature = 2;
+  optional TupleLiteralExpression signature = 3;
 }
 
 message ChoiceDeclaration {

common/fuzzing/proto_to_carbon.cpp

@@ -644,7 +644,7 @@ static auto DeclarationToCarbon(const Fuzzing::Declaration& declaration,
       for (const auto& alternative : choice.alternatives()) {
         out << sep;
         IdentifierToCarbon(alternative.name(), out);
-        ExpressionToCarbon(alternative.signature(), out);
+        TupleLiteralExpressionToCarbon(alternative.signature(), out);
       }
       out << "}";
       break;

explorer/ast/declaration.h

@@ -220,7 +220,7 @@ class ClassDeclaration : public Declaration {
 class AlternativeSignature : public AstNode {
  public:
   AlternativeSignature(SourceLocation source_loc, std::string name,
-                       Nonnull<Expression*> signature)
+                       Nonnull<TupleLiteral*> signature)
       : AstNode(AstNodeKind::AlternativeSignature, source_loc),
         name_(std::move(name)),
         signature_(signature) {}
@@ -233,12 +233,12 @@ class AlternativeSignature : public AstNode {
   }
 
   auto name() const -> const std::string& { return name_; }
-  auto signature() const -> const Expression& { return *signature_; }
-  auto signature() -> Expression& { return *signature_; }
+  auto signature() const -> const TupleLiteral& { return *signature_; }
+  auto signature() -> TupleLiteral& { return *signature_; }
 
  private:
   std::string name_;
-  Nonnull<Expression*> signature_;
+  Nonnull<TupleLiteral*> signature_;
 };
 
 class ChoiceDeclaration : public Declaration {

explorer/fuzzing/ast_to_proto.cpp

@@ -516,7 +516,7 @@ static auto DeclarationToProto(const Declaration& declaration)
         auto* alternative_proto = choice_proto->add_alternatives();
         alternative_proto->set_name(alternative->name());
         *alternative_proto->mutable_signature() =
-            ExpressionToProto(alternative->signature());
+            TupleLiteralExpressionToProto(alternative->signature());
       }
       break;
     }

explorer/fuzzing/fuzzer_corpus/3a2e6f830b6edea6bcf31348f30a12a27b36d496.textproto

@@ -0,0 +1,482 @@
+compilation_unit {
+  package_statement {
+    package_name: "ExplorerTest"
+  }
+  is_api: true
+  declarations {
+    choice {
+      name: "Ints"
+      alternatives {
+        name: "None"
+        signature {
+        }
+      }
+      alternatives {
+        name: "One"
+        signature {
+          fields {
+            int_type_literal {
+            }
+          }
+        }
+      }
+      alternatives {
+        name: "Two"
+        signature {
+          fields {
+            int_type_literal {
+            }
+          }
+          fields {
+            int_type_literal {
+            }
+          }
+        }
+      }
+    }
+  }
+  declarations {
+    function {
+      name: "Main"
+      param_pattern {
+      }
+      return_term {
+        kind: Expression
+        type {
+          int_type_literal {
+          }
+        }
+      }
+      body {
+        statements {
+          variable_definition {
+            pattern {
+              binding_pattern {
+                name: "x"
+                type {
+                  auto_pattern {
+                  }
+                }
+              }
+            }
+            init {
+              call {
+                function {
+                  field_access {
+                    field: "None"
+                    aggregate {
+                      identifier {
+                        name: "Ints"
+                      }
+                    }
+                  }
+                }
+                argument {
+                  tuple_literal {
+                  }
+                }
+              }
+            }
+          }
+        }
+        statements {
+          variable_definition {
+            pattern {
+              binding_pattern {
+                name: "y"
+                type {
+                  auto_pattern {
+                  }
+                }
+              }
+            }
+            init {
+              call {
+                function {
+                  field_access {
+                    field: "One"
+                    aggregate {
+                      identifier {
+                        name: "Ints"
+                      }
+                    }
+                  }
+                }
+                argument {
+                  tuple_literal {
+                    fields {
+                      int_literal {
+                        value: 42
+                      }
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+        statements {
+          variable_definition {
+            pattern {
+              binding_pattern {
+                name: "n"
+                type {
+                  auto_pattern {
+                  }
+                }
+              }
+            }
+            init {
+              int_literal {
+                value: 0
+              }
+            }
+          }
+        }
+        statements {
+          match {
+            expression {
+              identifier {
+                name: "y"
+              }
+            }
+            clauses {
+              pattern {
+                expression_pattern {
+                  expression {
+                    field_access {
+                      field: "None"
+                      aggregate {
+                        identifier {
+                          name: "Ints"
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+              statement {
+                assign {
+                  lhs {
+                    identifier {
+                      name: "n"
+                    }
+                  }
+                  rhs {
+                    primitive_operator {
+                      op: Add
+                      arguments {
+                        identifier {
+                          name: "n"
+                        }
+                      }
+                      arguments {
+                        int_literal {
+                          value: 2
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+            }
+            clauses {
+              pattern {
+                alternative_pattern {
+                  choice_type {
+                    identifier {
+                      name: "Ints"
+                    }
+                  }
+                  alternative_name: "One"
+                  arguments {
+                    fields {
+                      binding_pattern {
+                        name: "x"
+                        type {
+                          auto_pattern {
+                          }
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+              statement {
+                assign {
+                  lhs {
+                    identifier {
+                      name: "n"
+                    }
+                  }
+                  rhs {
+                    primitive_operator {
+                      op: Sub
+                      arguments {
+                        primitive_operator {
+                          op: Add
+                          arguments {
+                            identifier {
+                              name: "x"
+                            }
+                          }
+                          arguments {
+                            int_literal {
+                              value: 1
+                            }
+                          }
+                        }
+                      }
+                      arguments {
+                        int_literal {
+                          value: 42
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+            }
+            clauses {
+              pattern {
+                alternative_pattern {
+                  choice_type {
+                    identifier {
+                      name: "Ints"
+                    }
+                  }
+                  alternative_name: "Two"
+                  arguments {
+                    fields {
+                      binding_pattern {
+                        name: "a"
+                        type {
+                          auto_pattern {
+                          }
+                        }
+                      }
+                    }
+                    fields {
+                      binding_pattern {
+                        name: "b"
+                        type {
+                          auto_pattern {
+                          }
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+              statement {
+                assign {
+                  lhs {
+                    identifier {
+                      name: "n"
+                    }
+                  }
+                  rhs {
+                    int_literal {
+                      value: 2
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+        statements {
+          match {
+            expression {
+              identifier {
+                name: "x"
+              }
+            }
+            clauses {
+              pattern {
+                alternative_pattern {
+                  choice_type {
+                    identifier {
+                      name: "Ints"
+                    }
+                  }
+                  alternative_name: "One"
+                  arguments {
+                    fields {
+                      binding_pattern {
+                        name: "x"
+                        type {
+                          auto_pattern {
+                          }
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+              statement {
+                assign {
+                  lhs {
+                    identifier {
+                      name: "n"
+                    }
+                  }
+                  rhs {
+                    primitive_operator {
+                      op: Add
+                      arguments {
+                        identifier {
+                          name: "x"
+                        }
+                      }
+                      arguments {
+                        int_literal {
+                          value: 2
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+            }
+            clauses {
+              pattern {
+                expression_pattern {
+                  expression {
+                    call {
+                      function {
+                        field_access {
+                          field: "None"
+                          aggregate {
+                            identifier {
+                              name: "Ints"
+                            }
+                          }
+                        }
+                      }
+                      argument {
+                        tuple_literal {
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+              statement {
+                assign {
+                  lhs {
+                    identifier {
+                      name: "n"
+                    }
+                  }
+                  rhs {
+                    primitive_operator {
+                      op: Sub
+                      arguments {
+                        identifier {
+                          name: "n"
+                        }
+                      }
+                      arguments {
+                        int_literal {
+                          value: 1
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+            }
+            clauses {
+              pattern {
+                alternative_pattern {
+                  choice_type {
+                    identifier {
+                      name: "Ints"
+                    }
+                  }
+                  alternative_name: "Two"
+                  arguments {
+                    fields {
+                      binding_pattern {
+                        name: "x"
+                        type {
+                          auto_pattern {
+                          }
+                        }
+                      }
+                    }
+                    fields {
+                      binding_pattern {
+                        name: "y"
+                        type {
+                          auto_pattern {
+                          }
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+              statement {
+                assign {
+                  lhs {
+                    identifier {
+                      name: "n"
+                    }
+                  }
+                  rhs {
+                    int_literal {
+                      value: 5
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+        statements {
+          return_statement {
+            expression {
+              identifier {
+                name: "n"
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+  declarations {
+    choice {
+      name: "MoreInts"
+      alternatives {
+        name: "None"
+        signature {
+        }
+      }
+      alternatives {
+        name: "One"
+        signature {
+          fields {
+            int_type_literal {
+            }
+          }
+        }
+      }
+      alternatives {
+        name: "Two"
+        signature {
+          fields {
+            int_type_literal {
+            }
+          }
+          fields {
+            int_type_literal {
+            }
+          }
+        }
+      }
+    }
+  }
+}

explorer/fuzzing/fuzzer_corpus/90c1b392ccc71913bc6166593f51626e0cebb737.textproto

@@ -0,0 +1,299 @@
+compilation_unit {
+  package_statement {
+    package_name: "ExplorerTest"
+  }
+  is_api: true
+  declarations {
+    choice {
+      name: "Ints"
+      alternatives {
+        name: "None"
+        signature {
+        }
+      }
+      alternatives {
+        name: "One"
+        signature {
+          fields {
+            int_type_literal {
+            }
+          }
+        }
+      }
+      alternatives {
+        name: "Two"
+        signature {
+          fields {
+            int_type_literal {
+            }
+          }
+          fields {
+            int_type_literal {
+            }
+          }
+        }
+      }
+    }
+  }
+  declarations {
+    function {
+      name: "Main"
+      param_pattern {
+      }
+      return_term {
+        kind: Expression
+        type {
+          int_type_literal {
+          }
+        }
+      }
+      body {
+        statements {
+          variable_definition {
+            pattern {
+              tuple_pattern {
+                fields {
+                  var_pattern {
+                    pattern {
+                      alternative_pattern {
+                        choice_type {
+                          identifier {
+                            name: "Ints"
+                          }
+                        }
+                        alternative_name: "Two"
+                        arguments {
+                          fields {
+                            binding_pattern {
+                              name: "a1"
+                              type {
+                                auto_pattern {
+                                }
+                              }
+                            }
+                          }
+                          fields {
+                            var_pattern {
+                              pattern {
+                                binding_pattern {
+                                  name: "a2"
+                                  type {
+                                    auto_pattern {
+                                    }
+                                  }
+                                }
+                              }
+                            }
+                          }
+                        }
+                      }
+                    }
+                  }
+                }
+                fields {
+                  tuple_pattern {
+                    fields {
+                      tuple_pattern {
+                        fields {
+                          binding_pattern {
+                            name: "b"
+                            type {
+                              auto_pattern {
+                              }
+                            }
+                          }
+                        }
+                        fields {
+                          var_pattern {
+                            pattern {
+                              binding_pattern {
+                                name: "c"
+                                type {
+                                  auto_pattern {
+                                  }
+                                }
+                              }
+                            }
+                          }
+                        }
+                      }
+                    }
+                    fields {
+                      var_pattern {
+                        pattern {
+                          tuple_pattern {
+                            fields {
+                              binding_pattern {
+                                name: "d"
+                                type {
+                                  auto_pattern {
+                                  }
+                                }
+                              }
+                            }
+                            fields {
+                              binding_pattern {
+                                name: "e"
+                                type {
+                                  auto_pattern {
+                                  }
+                                }
+                              }
+                            }
+                          }
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+            }
+            init {
+              tuple_literal {
+                fields {
+                  call {
+                    function {
+                      field_access {
+                        field: "Two"
+                        aggregate {
+                          identifier {
+                            name: "Ints"
+                          }
+                        }
+                      }
+                    }
+                    argument {
+                      tuple_literal {
+                        fields {
+                          int_literal {
+                            value: 1
+                          }
+                        }
+                        fields {
+                          int_literal {
+                            value: 10
+                          }
+                        }
+                      }
+                    }
+                  }
+                }
+                fields {
+                  tuple_literal {
+                    fields {
+                      tuple_literal {
+                        fields {
+                          int_literal {
+                            value: 2
+                          }
+                        }
+                        fields {
+                          int_literal {
+                            value: 3
+                          }
+                        }
+                      }
+                    }
+                    fields {
+                      tuple_literal {
+                        fields {
+                          int_literal {
+                            value: 4
+                          }
+                        }
+                        fields {
+                          int_literal {
+                            value: 5
+                          }
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+        statements {
+          assign {
+            lhs {
+              identifier {
+                name: "a1"
+              }
+            }
+            rhs {
+              int_literal {
+                value: 0
+              }
+            }
+          }
+        }
+        statements {
+          assign {
+            lhs {
+              identifier {
+                name: "a2"
+              }
+            }
+            rhs {
+              int_literal {
+                value: 0
+              }
+            }
+          }
+        }
+        statements {
+          assign {
+            lhs {
+              identifier {
+                name: "c"
+              }
+            }
+            rhs {
+              int_literal {
+                value: 0
+              }
+            }
+          }
+        }
+        statements {
+          assign {
+            lhs {
+              identifier {
+                name: "d"
+              }
+            }
+            rhs {
+              int_literal {
+                value: 0
+              }
+            }
+          }
+        }
+        statements {
+          assign {
+            lhs {
+              identifier {
+                name: "e"
+              }
+            }
+            rhs {
+              int_literal {
+                value: 0
+              }
+            }
+          }
+        }
+        statements {
+          return_statement {
+            expression {
+              int_literal {
+                value: 0
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+}

explorer/fuzzing/fuzzer_corpus/c7c6e4477db2a3b777e740964a09a379684261d8.textproto

@@ -0,0 +1,28 @@
+compilation_unit {
+  declarations {
+    choice {
+      alternatives {
+        signature {
+          fields {
+            primitive_operator {
+              arguments {
+                intrinsic {
+                  argument {
+                    fields {
+                      primitive_operator {
+                        arguments {
+                          identifier {
+                          }
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+}

explorer/fuzzing/fuzzer_corpus/dedba2ac81916ee306624a2ac3db2a3c7a4ea5ad.textproto

@@ -1,26 +0,0 @@
-compilation_unit {
-  declarations {
-    choice {
-      alternatives {
-        signature {
-          primitive_operator {
-            arguments {
-              intrinsic {
-                argument {
-                  fields {
-                    primitive_operator {
-                      arguments {
-                        identifier {
-                        }
-                      }
-                    }
-                  }
-                }
-              }
-            }
-          }
-        }
-      }
-    }
-  }
-}