diff --git a/crates/biome_graphql_parser/src/parser/definitions/mod.rs b/crates/biome_graphql_parser/src/parser/definitions/mod.rs
index 3b33e39c1429..f9ce303f602b 100644
--- a/crates/biome_graphql_parser/src/parser/definitions/mod.rs
+++ b/crates/biome_graphql_parser/src/parser/definitions/mod.rs
@@ -5,6 +5,7 @@ mod object;
 mod operation;
 mod scalar;
 mod schema;
+mod union;
 
 use crate::parser::{parse_error::expected_any_definition, GraphqlParser};
 use biome_graphql_syntax::GraphqlSyntaxKind::{self, *};
@@ -20,6 +21,7 @@ use self::{
     operation::{is_at_operation, parse_operation_definition},
     scalar::{is_at_scalar_type_definition, parse_scalar_type_definition},
     schema::{is_at_schema_definition, parse_schema_definition},
+    union::{is_at_union_type_definition, parse_union_type_definition},
 };
 pub(crate) use operation::is_at_selection_set_end;
 
@@ -76,6 +78,8 @@ fn parse_definition(p: &mut GraphqlParser) -> ParsedSyntax {
         parse_object_type_definition(p)
     } else if is_at_interface_type_definition(p) {
         parse_interface_type_definition(p)
+    } else if is_at_union_type_definition(p) {
+        parse_union_type_definition(p)
     } else {
         Absent
     }
@@ -90,4 +94,5 @@ fn is_at_definition(p: &mut GraphqlParser<'_>) -> bool {
         || is_at_scalar_type_definition(p)
         || is_at_object_type_definition(p)
         || is_at_interface_type_definition(p)
+        || is_at_union_type_definition(p)
 }
diff --git a/crates/biome_graphql_parser/src/parser/definitions/union.rs b/crates/biome_graphql_parser/src/parser/definitions/union.rs
new file mode 100644
index 000000000000..473897541c9f
--- /dev/null
+++ b/crates/biome_graphql_parser/src/parser/definitions/union.rs
@@ -0,0 +1,139 @@
+use crate::parser::{
+    directive::DirectiveList,
+    is_at_name, parse_description,
+    parse_error::{expected_name, expected_named_type},
+    parse_name,
+    r#type::parse_named_type,
+    value::is_at_string,
+    GraphqlParser,
+};
+use biome_graphql_syntax::{
+    GraphqlSyntaxKind::{self, *},
+    T,
+};
+use biome_parser::{
+    parse_lists::{ParseNodeList, ParseSeparatedList},
+    parse_recovery::ParseRecovery,
+    parsed_syntax::ParsedSyntax,
+    prelude::ParsedSyntax::*,
+    token_source::TokenSource,
+    Parser,
+};
+
+use super::is_at_definition;
+
+#[inline]
+pub(crate) fn parse_union_type_definition(p: &mut GraphqlParser) -> ParsedSyntax {
+    if !is_at_union_type_definition(p) {
+        return Absent;
+    }
+    let m = p.start();
+
+    // description is optional
+    parse_description(p).ok();
+
+    p.bump(T![union]);
+
+    parse_name(p).or_add_diagnostic(p, expected_name);
+
+    DirectiveList.parse_list(p);
+
+    // union member types are optional
+    parse_union_member_types(p).ok();
+
+    Present(m.complete(p, GRAPHQL_UNION_TYPE_DEFINITION))
+}
+
+#[inline]
+fn parse_union_member_types(p: &mut GraphqlParser) -> ParsedSyntax {
+    if !is_at_union_member_types(p) {
+        return Absent;
+    }
+    let m = p.start();
+    p.expect(T![=]);
+
+    if p.at(T![|]) {
+        p.bump(T![|]);
+    }
+
+    let position = p.source().position();
+    UnionMemberTypeList.parse_list(p);
+
+    // has not progressed, meaning no union member types were parsed
+    if position == p.source().position() {
+        p.error(expected_named_type(p, p.cur_range()));
+    }
+    Present(m.complete(p, GRAPHQL_UNION_MEMBER_TYPES))
+}
+
+#[derive(Default)]
+struct UnionMemberTypeList;
+
+impl ParseSeparatedList for UnionMemberTypeList {
+    type Kind = GraphqlSyntaxKind;
+    type Parser<'source> = GraphqlParser<'source>;
+
+    const LIST_KIND: Self::Kind = GRAPHQL_UNION_MEMBER_TYPE_LIST;
+
+    fn parse_element(&mut self, p: &mut Self::Parser<'_>) -> ParsedSyntax {
+        parse_named_type(p)
+    }
+
+    fn is_at_list_end(&self, p: &mut Self::Parser<'_>) -> bool {
+        is_at_union_member_types_end(p)
+    }
+
+    fn recover(
+        &mut self,
+        p: &mut Self::Parser<'_>,
+        parsed_element: ParsedSyntax,
+    ) -> biome_parser::parse_recovery::RecoveryResult {
+        parsed_element.or_recover(p, &UnionMemberListParseRecovery, expected_named_type)
+    }
+
+    fn separating_element_kind(&mut self) -> Self::Kind {
+        T![|]
+    }
+
+    fn allow_trailing_separating_element(&self) -> bool {
+        false
+    }
+}
+
+struct UnionMemberListParseRecovery;
+
+impl ParseRecovery for UnionMemberListParseRecovery {
+    type Kind = GraphqlSyntaxKind;
+    type Parser<'source> = GraphqlParser<'source>;
+    const RECOVERED_KIND: Self::Kind = GRAPHQL_BOGUS;
+
+    fn is_at_recovered(&self, p: &mut Self::Parser<'_>) -> bool {
+        p.at(T![|])
+        // After a union definition is a new type definition so it's safe to
+        // assume any name we see before a new type definition is a union
+        // member type
+        || is_at_name(p)
+        || is_at_union_member_types_end(p)
+    }
+}
+
+#[inline]
+pub(crate) fn is_at_union_type_definition(p: &mut GraphqlParser<'_>) -> bool {
+    p.at(T![union]) || (is_at_string(p) && p.nth_at(1, T![union]))
+}
+
+#[inline]
+fn is_at_union_member_types(p: &mut GraphqlParser<'_>) -> bool {
+    p.at(T![=])
+    // missing =
+    || p.at(T![|])
+    // missing both = and |. After a union definition is a new type definition
+    // so it's safe to assume any name we see before a new type definition is
+    // a union member type
+    || is_at_name(p)
+}
+
+#[inline]
+fn is_at_union_member_types_end(p: &mut GraphqlParser<'_>) -> bool {
+    is_at_definition(p)
+}
diff --git a/crates/biome_graphql_parser/tests/graphql_test_suite/err/union.graphql b/crates/biome_graphql_parser/tests/graphql_test_suite/err/union.graphql
new file mode 100644
index 000000000000..6b7329792600
--- /dev/null
+++ b/crates/biome_graphql_parser/tests/graphql_test_suite/err/union.graphql
@@ -0,0 +1,14 @@
+union SearchResult = Photo |
+
+union SearchResult
+	| Photo
+	| Person
+
+
+union SearchResult |
+
+union SearchResult =
+
+union SearchResult = |
+
+union SearchResult @ =
diff --git a/crates/biome_graphql_parser/tests/graphql_test_suite/err/union.graphql.snap b/crates/biome_graphql_parser/tests/graphql_test_suite/err/union.graphql.snap
new file mode 100644
index 000000000000..c7d690efe6d3
--- /dev/null
+++ b/crates/biome_graphql_parser/tests/graphql_test_suite/err/union.graphql.snap
@@ -0,0 +1,361 @@
+---
+source: crates/biome_graphql_parser/tests/spec_test.rs
+expression: snapshot
+---
+## Input
+```graphql
+union SearchResult = Photo |
+
+union SearchResult
+	| Photo
+	| Person
+
+
+union SearchResult |
+
+union SearchResult =
+
+union SearchResult = |
+
+union SearchResult @ =
+
+```
+
+## AST
+
+```
+GraphqlRoot {
+    bom_token: missing (optional),
+    definitions: GraphqlDefinitionList [
+        GraphqlUnionTypeDefinition {
+            description: missing (optional),
+            union_token: UNION_KW@0..6 "union" [] [Whitespace(" ")],
+            name: GraphqlName {
+                value_token: GRAPHQL_NAME@6..19 "SearchResult" [] [Whitespace(" ")],
+            },
+            directives: GraphqlDirectiveList [],
+            union_members: GraphqlUnionMemberTypes {
+                eq_token: EQ@19..21 "=" [] [Whitespace(" ")],
+                bitwise_or_token: missing (optional),
+                members: GraphqlUnionMemberTypeList [
+                    GraphqlNamedType {
+                        name: GraphqlName {
+                            value_token: GRAPHQL_NAME@21..27 "Photo" [] [Whitespace(" ")],
+                        },
+                    },
+                    PIPE@27..28 "|" [] [],
+                    missing element,
+                ],
+            },
+        },
+        GraphqlUnionTypeDefinition {
+            description: missing (optional),
+            union_token: UNION_KW@28..36 "union" [Newline("\n"), Newline("\n")] [Whitespace(" ")],
+            name: GraphqlName {
+                value_token: GRAPHQL_NAME@36..48 "SearchResult" [] [],
+            },
+            directives: GraphqlDirectiveList [],
+            union_members: GraphqlUnionMemberTypes {
+                eq_token: missing (required),
+                bitwise_or_token: PIPE@48..52 "|" [Newline("\n"), Whitespace("\t")] [Whitespace(" ")],
+                members: GraphqlUnionMemberTypeList [
+                    GraphqlNamedType {
+                        name: GraphqlName {
+                            value_token: GRAPHQL_NAME@52..57 "Photo" [] [],
+                        },
+                    },
+                    PIPE@57..61 "|" [Newline("\n"), Whitespace("\t")] [Whitespace(" ")],
+                    GraphqlNamedType {
+                        name: GraphqlName {
+                            value_token: GRAPHQL_NAME@61..67 "Person" [] [],
+                        },
+                    },
+                ],
+            },
+        },
+        GraphqlUnionTypeDefinition {
+            description: missing (optional),
+            union_token: UNION_KW@67..76 "union" [Newline("\n"), Newline("\n"), Newline("\n")] [Whitespace(" ")],
+            name: GraphqlName {
+                value_token: GRAPHQL_NAME@76..89 "SearchResult" [] [Whitespace(" ")],
+            },
+            directives: GraphqlDirectiveList [],
+            union_members: GraphqlUnionMemberTypes {
+                eq_token: missing (required),
+                bitwise_or_token: PIPE@89..90 "|" [] [],
+                members: GraphqlUnionMemberTypeList [],
+            },
+        },
+        GraphqlUnionTypeDefinition {
+            description: missing (optional),
+            union_token: UNION_KW@90..98 "union" [Newline("\n"), Newline("\n")] [Whitespace(" ")],
+            name: GraphqlName {
+                value_token: GRAPHQL_NAME@98..111 "SearchResult" [] [Whitespace(" ")],
+            },
+            directives: GraphqlDirectiveList [],
+            union_members: GraphqlUnionMemberTypes {
+                eq_token: EQ@111..112 "=" [] [],
+                bitwise_or_token: missing (optional),
+                members: GraphqlUnionMemberTypeList [],
+            },
+        },
+        GraphqlUnionTypeDefinition {
+            description: missing (optional),
+            union_token: UNION_KW@112..120 "union" [Newline("\n"), Newline("\n")] [Whitespace(" ")],
+            name: GraphqlName {
+                value_token: GRAPHQL_NAME@120..133 "SearchResult" [] [Whitespace(" ")],
+            },
+            directives: GraphqlDirectiveList [],
+            union_members: GraphqlUnionMemberTypes {
+                eq_token: EQ@133..135 "=" [] [Whitespace(" ")],
+                bitwise_or_token: PIPE@135..136 "|" [] [],
+                members: GraphqlUnionMemberTypeList [],
+            },
+        },
+        GraphqlUnionTypeDefinition {
+            description: missing (optional),
+            union_token: UNION_KW@136..144 "union" [Newline("\n"), Newline("\n")] [Whitespace(" ")],
+            name: GraphqlName {
+                value_token: GRAPHQL_NAME@144..157 "SearchResult" [] [Whitespace(" ")],
+            },
+            directives: GraphqlDirectiveList [
+                GraphqlDirective {
+                    at_token: AT@157..159 "@" [] [Whitespace(" ")],
+                    name: missing (required),
+                    arguments: missing (optional),
+                },
+            ],
+            union_members: GraphqlUnionMemberTypes {
+                eq_token: EQ@159..160 "=" [] [],
+                bitwise_or_token: missing (optional),
+                members: GraphqlUnionMemberTypeList [],
+            },
+        },
+    ],
+    eof_token: EOF@160..161 "" [Newline("\n")] [],
+}
+```
+
+## CST
+
+```
+0: GRAPHQL_ROOT@0..161
+  0: (empty)
+  1: GRAPHQL_DEFINITION_LIST@0..160
+    0: GRAPHQL_UNION_TYPE_DEFINITION@0..28
+      0: (empty)
+      1: UNION_KW@0..6 "union" [] [Whitespace(" ")]
+      2: GRAPHQL_NAME@6..19
+        0: GRAPHQL_NAME@6..19 "SearchResult" [] [Whitespace(" ")]
+      3: GRAPHQL_DIRECTIVE_LIST@19..19
+      4: GRAPHQL_UNION_MEMBER_TYPES@19..28
+        0: EQ@19..21 "=" [] [Whitespace(" ")]
+        1: (empty)
+        2: GRAPHQL_UNION_MEMBER_TYPE_LIST@21..28
+          0: GRAPHQL_NAMED_TYPE@21..27
+            0: GRAPHQL_NAME@21..27
+              0: GRAPHQL_NAME@21..27 "Photo" [] [Whitespace(" ")]
+          1: PIPE@27..28 "|" [] []
+          2: (empty)
+    1: GRAPHQL_UNION_TYPE_DEFINITION@28..67
+      0: (empty)
+      1: UNION_KW@28..36 "union" [Newline("\n"), Newline("\n")] [Whitespace(" ")]
+      2: GRAPHQL_NAME@36..48
+        0: GRAPHQL_NAME@36..48 "SearchResult" [] []
+      3: GRAPHQL_DIRECTIVE_LIST@48..48
+      4: GRAPHQL_UNION_MEMBER_TYPES@48..67
+        0: (empty)
+        1: PIPE@48..52 "|" [Newline("\n"), Whitespace("\t")] [Whitespace(" ")]
+        2: GRAPHQL_UNION_MEMBER_TYPE_LIST@52..67
+          0: GRAPHQL_NAMED_TYPE@52..57
+            0: GRAPHQL_NAME@52..57
+              0: GRAPHQL_NAME@52..57 "Photo" [] []
+          1: PIPE@57..61 "|" [Newline("\n"), Whitespace("\t")] [Whitespace(" ")]
+          2: GRAPHQL_NAMED_TYPE@61..67
+            0: GRAPHQL_NAME@61..67
+              0: GRAPHQL_NAME@61..67 "Person" [] []
+    2: GRAPHQL_UNION_TYPE_DEFINITION@67..90
+      0: (empty)
+      1: UNION_KW@67..76 "union" [Newline("\n"), Newline("\n"), Newline("\n")] [Whitespace(" ")]
+      2: GRAPHQL_NAME@76..89
+        0: GRAPHQL_NAME@76..89 "SearchResult" [] [Whitespace(" ")]
+      3: GRAPHQL_DIRECTIVE_LIST@89..89
+      4: GRAPHQL_UNION_MEMBER_TYPES@89..90
+        0: (empty)
+        1: PIPE@89..90 "|" [] []
+        2: GRAPHQL_UNION_MEMBER_TYPE_LIST@90..90
+    3: GRAPHQL_UNION_TYPE_DEFINITION@90..112
+      0: (empty)
+      1: UNION_KW@90..98 "union" [Newline("\n"), Newline("\n")] [Whitespace(" ")]
+      2: GRAPHQL_NAME@98..111
+        0: GRAPHQL_NAME@98..111 "SearchResult" [] [Whitespace(" ")]
+      3: GRAPHQL_DIRECTIVE_LIST@111..111
+      4: GRAPHQL_UNION_MEMBER_TYPES@111..112
+        0: EQ@111..112 "=" [] []
+        1: (empty)
+        2: GRAPHQL_UNION_MEMBER_TYPE_LIST@112..112
+    4: GRAPHQL_UNION_TYPE_DEFINITION@112..136
+      0: (empty)
+      1: UNION_KW@112..120 "union" [Newline("\n"), Newline("\n")] [Whitespace(" ")]
+      2: GRAPHQL_NAME@120..133
+        0: GRAPHQL_NAME@120..133 "SearchResult" [] [Whitespace(" ")]
+      3: GRAPHQL_DIRECTIVE_LIST@133..133
+      4: GRAPHQL_UNION_MEMBER_TYPES@133..136
+        0: EQ@133..135 "=" [] [Whitespace(" ")]
+        1: PIPE@135..136 "|" [] []
+        2: GRAPHQL_UNION_MEMBER_TYPE_LIST@136..136
+    5: GRAPHQL_UNION_TYPE_DEFINITION@136..160
+      0: (empty)
+      1: UNION_KW@136..144 "union" [Newline("\n"), Newline("\n")] [Whitespace(" ")]
+      2: GRAPHQL_NAME@144..157
+        0: GRAPHQL_NAME@144..157 "SearchResult" [] [Whitespace(" ")]
+      3: GRAPHQL_DIRECTIVE_LIST@157..159
+        0: GRAPHQL_DIRECTIVE@157..159
+          0: AT@157..159 "@" [] [Whitespace(" ")]
+          1: (empty)
+          2: (empty)
+      4: GRAPHQL_UNION_MEMBER_TYPES@159..160
+        0: EQ@159..160 "=" [] []
+        1: (empty)
+        2: GRAPHQL_UNION_MEMBER_TYPE_LIST@160..160
+  2: EOF@160..161 "" [Newline("\n")] []
+
+```
+
+## Diagnostics
+
+```
+union.graphql:3:1 parse ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  × Expected a named type but instead found 'union'.
+  
+    1 │ union SearchResult = Photo |
+    2 │ 
+  > 3 │ union SearchResult
+      │ ^^^^^
+    4 │ 	| Photo
+    5 │ 	| Person
+  
+  i Expected a named type here.
+  
+    1 │ union SearchResult = Photo |
+    2 │ 
+  > 3 │ union SearchResult
+      │ ^^^^^
+    4 │ 	| Photo
+    5 │ 	| Person
+  
+union.graphql:4:2 parse ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  × expected `=` but instead found `|`
+  
+    3 │ union SearchResult
+  > 4 │ 	| Photo
+      │ 	^
+    5 │ 	| Person
+    6 │ 
+  
+  i Remove |
+  
+union.graphql:8:20 parse ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  × expected `=` but instead found `|`
+  
+   > 8 │ union SearchResult |
+       │                    ^
+     9 │ 
+    10 │ union SearchResult =
+  
+  i Remove |
+  
+union.graphql:10:1 parse ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  × Expected a named type but instead found 'union'.
+  
+     8 │ union SearchResult |
+     9 │ 
+  > 10 │ union SearchResult =
+       │ ^^^^^
+    11 │ 
+    12 │ union SearchResult = |
+  
+  i Expected a named type here.
+  
+     8 │ union SearchResult |
+     9 │ 
+  > 10 │ union SearchResult =
+       │ ^^^^^
+    11 │ 
+    12 │ union SearchResult = |
+  
+union.graphql:12:1 parse ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  × Expected a named type but instead found 'union'.
+  
+    10 │ union SearchResult =
+    11 │ 
+  > 12 │ union SearchResult = |
+       │ ^^^^^
+    13 │ 
+    14 │ union SearchResult @ =
+  
+  i Expected a named type here.
+  
+    10 │ union SearchResult =
+    11 │ 
+  > 12 │ union SearchResult = |
+       │ ^^^^^
+    13 │ 
+    14 │ union SearchResult @ =
+  
+union.graphql:14:1 parse ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  × Expected a named type but instead found 'union'.
+  
+    12 │ union SearchResult = |
+    13 │ 
+  > 14 │ union SearchResult @ =
+       │ ^^^^^
+    15 │ 
+  
+  i Expected a named type here.
+  
+    12 │ union SearchResult = |
+    13 │ 
+  > 14 │ union SearchResult @ =
+       │ ^^^^^
+    15 │ 
+  
+union.graphql:14:22 parse ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  × Expected a name but instead found '='.
+  
+    12 │ union SearchResult = |
+    13 │ 
+  > 14 │ union SearchResult @ =
+       │                      ^
+    15 │ 
+  
+  i Expected a name here.
+  
+    12 │ union SearchResult = |
+    13 │ 
+  > 14 │ union SearchResult @ =
+       │                      ^
+    15 │ 
+  
+union.graphql:15:1 parse ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  × Expected a named type but instead found the end of the file.
+  
+    14 │ union SearchResult @ =
+  > 15 │ 
+       │ 
+  
+  i Expected a named type here.
+  
+    14 │ union SearchResult @ =
+  > 15 │ 
+       │ 
+  
+```
diff --git a/crates/biome_graphql_parser/tests/graphql_test_suite/ok/definitions/union.graphql b/crates/biome_graphql_parser/tests/graphql_test_suite/ok/definitions/union.graphql
new file mode 100644
index 000000000000..da90c0882c35
--- /dev/null
+++ b/crates/biome_graphql_parser/tests/graphql_test_suite/ok/definitions/union.graphql
@@ -0,0 +1,11 @@
+union SearchResult = Photo | Person
+
+union SearchResult =
+	| Photo
+	| Person
+
+union SearchResult
+
+union SearchResult @deprecated
+
+union SearchResult @deprecated = Photo | Person
diff --git a/crates/biome_graphql_parser/tests/graphql_test_suite/ok/definitions/union.graphql.snap b/crates/biome_graphql_parser/tests/graphql_test_suite/ok/definitions/union.graphql.snap
new file mode 100644
index 000000000000..a8411d55de77
--- /dev/null
+++ b/crates/biome_graphql_parser/tests/graphql_test_suite/ok/definitions/union.graphql.snap
@@ -0,0 +1,224 @@
+---
+source: crates/biome_graphql_parser/tests/spec_test.rs
+expression: snapshot
+---
+## Input
+```graphql
+union SearchResult = Photo | Person
+
+union SearchResult =
+	| Photo
+	| Person
+
+union SearchResult
+
+union SearchResult @deprecated
+
+union SearchResult @deprecated = Photo | Person
+
+```
+
+## AST
+
+```
+GraphqlRoot {
+    bom_token: missing (optional),
+    definitions: GraphqlDefinitionList [
+        GraphqlUnionTypeDefinition {
+            description: missing (optional),
+            union_token: UNION_KW@0..6 "union" [] [Whitespace(" ")],
+            name: GraphqlName {
+                value_token: GRAPHQL_NAME@6..19 "SearchResult" [] [Whitespace(" ")],
+            },
+            directives: GraphqlDirectiveList [],
+            union_members: GraphqlUnionMemberTypes {
+                eq_token: EQ@19..21 "=" [] [Whitespace(" ")],
+                bitwise_or_token: missing (optional),
+                members: GraphqlUnionMemberTypeList [
+                    GraphqlNamedType {
+                        name: GraphqlName {
+                            value_token: GRAPHQL_NAME@21..27 "Photo" [] [Whitespace(" ")],
+                        },
+                    },
+                    PIPE@27..29 "|" [] [Whitespace(" ")],
+                    GraphqlNamedType {
+                        name: GraphqlName {
+                            value_token: GRAPHQL_NAME@29..35 "Person" [] [],
+                        },
+                    },
+                ],
+            },
+        },
+        GraphqlUnionTypeDefinition {
+            description: missing (optional),
+            union_token: UNION_KW@35..43 "union" [Newline("\n"), Newline("\n")] [Whitespace(" ")],
+            name: GraphqlName {
+                value_token: GRAPHQL_NAME@43..56 "SearchResult" [] [Whitespace(" ")],
+            },
+            directives: GraphqlDirectiveList [],
+            union_members: GraphqlUnionMemberTypes {
+                eq_token: EQ@56..57 "=" [] [],
+                bitwise_or_token: PIPE@57..61 "|" [Newline("\n"), Whitespace("\t")] [Whitespace(" ")],
+                members: GraphqlUnionMemberTypeList [
+                    GraphqlNamedType {
+                        name: GraphqlName {
+                            value_token: GRAPHQL_NAME@61..66 "Photo" [] [],
+                        },
+                    },
+                    PIPE@66..70 "|" [Newline("\n"), Whitespace("\t")] [Whitespace(" ")],
+                    GraphqlNamedType {
+                        name: GraphqlName {
+                            value_token: GRAPHQL_NAME@70..76 "Person" [] [],
+                        },
+                    },
+                ],
+            },
+        },
+        GraphqlUnionTypeDefinition {
+            description: missing (optional),
+            union_token: UNION_KW@76..84 "union" [Newline("\n"), Newline("\n")] [Whitespace(" ")],
+            name: GraphqlName {
+                value_token: GRAPHQL_NAME@84..96 "SearchResult" [] [],
+            },
+            directives: GraphqlDirectiveList [],
+            union_members: missing (optional),
+        },
+        GraphqlUnionTypeDefinition {
+            description: missing (optional),
+            union_token: UNION_KW@96..104 "union" [Newline("\n"), Newline("\n")] [Whitespace(" ")],
+            name: GraphqlName {
+                value_token: GRAPHQL_NAME@104..117 "SearchResult" [] [Whitespace(" ")],
+            },
+            directives: GraphqlDirectiveList [
+                GraphqlDirective {
+                    at_token: AT@117..118 "@" [] [],
+                    name: GraphqlName {
+                        value_token: GRAPHQL_NAME@118..128 "deprecated" [] [],
+                    },
+                    arguments: missing (optional),
+                },
+            ],
+            union_members: missing (optional),
+        },
+        GraphqlUnionTypeDefinition {
+            description: missing (optional),
+            union_token: UNION_KW@128..136 "union" [Newline("\n"), Newline("\n")] [Whitespace(" ")],
+            name: GraphqlName {
+                value_token: GRAPHQL_NAME@136..149 "SearchResult" [] [Whitespace(" ")],
+            },
+            directives: GraphqlDirectiveList [
+                GraphqlDirective {
+                    at_token: AT@149..150 "@" [] [],
+                    name: GraphqlName {
+                        value_token: GRAPHQL_NAME@150..161 "deprecated" [] [Whitespace(" ")],
+                    },
+                    arguments: missing (optional),
+                },
+            ],
+            union_members: GraphqlUnionMemberTypes {
+                eq_token: EQ@161..163 "=" [] [Whitespace(" ")],
+                bitwise_or_token: missing (optional),
+                members: GraphqlUnionMemberTypeList [
+                    GraphqlNamedType {
+                        name: GraphqlName {
+                            value_token: GRAPHQL_NAME@163..169 "Photo" [] [Whitespace(" ")],
+                        },
+                    },
+                    PIPE@169..171 "|" [] [Whitespace(" ")],
+                    GraphqlNamedType {
+                        name: GraphqlName {
+                            value_token: GRAPHQL_NAME@171..177 "Person" [] [],
+                        },
+                    },
+                ],
+            },
+        },
+    ],
+    eof_token: EOF@177..178 "" [Newline("\n")] [],
+}
+```
+
+## CST
+
+```
+0: GRAPHQL_ROOT@0..178
+  0: (empty)
+  1: GRAPHQL_DEFINITION_LIST@0..177
+    0: GRAPHQL_UNION_TYPE_DEFINITION@0..35
+      0: (empty)
+      1: UNION_KW@0..6 "union" [] [Whitespace(" ")]
+      2: GRAPHQL_NAME@6..19
+        0: GRAPHQL_NAME@6..19 "SearchResult" [] [Whitespace(" ")]
+      3: GRAPHQL_DIRECTIVE_LIST@19..19
+      4: GRAPHQL_UNION_MEMBER_TYPES@19..35
+        0: EQ@19..21 "=" [] [Whitespace(" ")]
+        1: (empty)
+        2: GRAPHQL_UNION_MEMBER_TYPE_LIST@21..35
+          0: GRAPHQL_NAMED_TYPE@21..27
+            0: GRAPHQL_NAME@21..27
+              0: GRAPHQL_NAME@21..27 "Photo" [] [Whitespace(" ")]
+          1: PIPE@27..29 "|" [] [Whitespace(" ")]
+          2: GRAPHQL_NAMED_TYPE@29..35
+            0: GRAPHQL_NAME@29..35
+              0: GRAPHQL_NAME@29..35 "Person" [] []
+    1: GRAPHQL_UNION_TYPE_DEFINITION@35..76
+      0: (empty)
+      1: UNION_KW@35..43 "union" [Newline("\n"), Newline("\n")] [Whitespace(" ")]
+      2: GRAPHQL_NAME@43..56
+        0: GRAPHQL_NAME@43..56 "SearchResult" [] [Whitespace(" ")]
+      3: GRAPHQL_DIRECTIVE_LIST@56..56
+      4: GRAPHQL_UNION_MEMBER_TYPES@56..76
+        0: EQ@56..57 "=" [] []
+        1: PIPE@57..61 "|" [Newline("\n"), Whitespace("\t")] [Whitespace(" ")]
+        2: GRAPHQL_UNION_MEMBER_TYPE_LIST@61..76
+          0: GRAPHQL_NAMED_TYPE@61..66
+            0: GRAPHQL_NAME@61..66
+              0: GRAPHQL_NAME@61..66 "Photo" [] []
+          1: PIPE@66..70 "|" [Newline("\n"), Whitespace("\t")] [Whitespace(" ")]
+          2: GRAPHQL_NAMED_TYPE@70..76
+            0: GRAPHQL_NAME@70..76
+              0: GRAPHQL_NAME@70..76 "Person" [] []
+    2: GRAPHQL_UNION_TYPE_DEFINITION@76..96
+      0: (empty)
+      1: UNION_KW@76..84 "union" [Newline("\n"), Newline("\n")] [Whitespace(" ")]
+      2: GRAPHQL_NAME@84..96
+        0: GRAPHQL_NAME@84..96 "SearchResult" [] []
+      3: GRAPHQL_DIRECTIVE_LIST@96..96
+      4: (empty)
+    3: GRAPHQL_UNION_TYPE_DEFINITION@96..128
+      0: (empty)
+      1: UNION_KW@96..104 "union" [Newline("\n"), Newline("\n")] [Whitespace(" ")]
+      2: GRAPHQL_NAME@104..117
+        0: GRAPHQL_NAME@104..117 "SearchResult" [] [Whitespace(" ")]
+      3: GRAPHQL_DIRECTIVE_LIST@117..128
+        0: GRAPHQL_DIRECTIVE@117..128
+          0: AT@117..118 "@" [] []
+          1: GRAPHQL_NAME@118..128
+            0: GRAPHQL_NAME@118..128 "deprecated" [] []
+          2: (empty)
+      4: (empty)
+    4: GRAPHQL_UNION_TYPE_DEFINITION@128..177
+      0: (empty)
+      1: UNION_KW@128..136 "union" [Newline("\n"), Newline("\n")] [Whitespace(" ")]
+      2: GRAPHQL_NAME@136..149
+        0: GRAPHQL_NAME@136..149 "SearchResult" [] [Whitespace(" ")]
+      3: GRAPHQL_DIRECTIVE_LIST@149..161
+        0: GRAPHQL_DIRECTIVE@149..161
+          0: AT@149..150 "@" [] []
+          1: GRAPHQL_NAME@150..161
+            0: GRAPHQL_NAME@150..161 "deprecated" [] [Whitespace(" ")]
+          2: (empty)
+      4: GRAPHQL_UNION_MEMBER_TYPES@161..177
+        0: EQ@161..163 "=" [] [Whitespace(" ")]
+        1: (empty)
+        2: GRAPHQL_UNION_MEMBER_TYPE_LIST@163..177
+          0: GRAPHQL_NAMED_TYPE@163..169
+            0: GRAPHQL_NAME@163..169
+              0: GRAPHQL_NAME@163..169 "Photo" [] [Whitespace(" ")]
+          1: PIPE@169..171 "|" [] [Whitespace(" ")]
+          2: GRAPHQL_NAMED_TYPE@171..177
+            0: GRAPHQL_NAME@171..177
+              0: GRAPHQL_NAME@171..177 "Person" [] []
+  2: EOF@177..178 "" [Newline("\n")] []
+
+```