Support enquoted field alias

Summary:
## Context
GraphQL Server team has a usecase for field aliases represented by string literals, e.g.:
https://www.internalfb.com/code/fbsource/[6eebb1a1e581]/www/flib/__generated__/GraphQLHackClientMeerkatStep/single_source/GraphQLIGClipsProfileQueryExperiment/GraphQLIGClipsProfileInWWWQueryIGQuery.php?lines=47

More context on "why": [workplace post](https://fb.workplace.com/groups/606728000165364/permalink/1863505397820945/)

This is already supported in WWW and IG parsers.

In this stack we're adding an *opt-in* support for literal aliases for Relay's parser.

## This diff
Parse field aliases when the feature is enabled.

 Adds support for field aliases specified as string literals, e.g.:
```
{ "1$alias": name }
```

Reviewed By: captbaritone

Differential Revision: D73563288

fbshipit-source-id: 8e46aea98b9427bf0edd2c0b1b769ede42392b28

Author: Arseniy Panfilov

compiler/crates/graphql-syntax/Cargo.toml

@@ -1,4 +1,4 @@
-# @generated by autocargo from //relay/oss/crates/graphql-syntax:[advance_schema_document_test,graphql-syntax,graphql-syntax_print_test,parse_document_test,parse_document_with_features_test,parse_executable_document_test,parse_executable_document_with_error_recovery_test,parse_schema_document_test]
+# @generated by autocargo from //relay/oss/crates/graphql-syntax:[advance_schema_document_test,graphql-syntax,graphql-syntax_print_test,parse_document_test,parse_document_with_enquoted_alias_test,parse_document_with_features_test,parse_executable_document_test,parse_executable_document_with_error_recovery_test,parse_schema_document_test]
 
 [package]
 name = "graphql-syntax"

compiler/crates/graphql-syntax/src/node/executable.rs

@@ -160,6 +160,11 @@ impl fmt::Display for Alias {
     }
 }
 
+pub enum IdentifierOrString {
+    Identifier(Identifier),
+    StringNode(StringNode),
+}
+
 #[derive(Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash)]
 pub struct TypeCondition {
     pub span: Span,

compiler/crates/graphql-syntax/src/parser.rs

@@ -1908,7 +1908,7 @@ impl<'a> Parser<'a> {
         let token = self.peek();
         match token.kind {
             TokenKind::Spread => self.parse_spread(),
-            TokenKind::Identifier => self.parse_field(),
+            TokenKind::Identifier | TokenKind::StringLiteral => self.parse_field(),
             // hint for invalid spreads
             TokenKind::Period | TokenKind::PeriodPeriod => {
                 let error = Diagnostic::error(
@@ -1929,13 +1929,49 @@ impl<'a> Parser<'a> {
         }
     }
 
+    fn parse_name_or_string_literal(&mut self) -> ParseResult<IdentifierOrString> {
+        let token_kind = self.peek_token_kind();
+        if token_kind == TokenKind::Identifier {
+            return Ok(IdentifierOrString::Identifier(self.parse_identifier()?));
+        }
+
+        let token = self.parse_token();
+        if !self.features.allow_string_literal_alias {
+            self.record_error(Diagnostic::error(
+                SyntaxError::Expected(TokenKind::Identifier),
+                Location::new(self.source_location, token.span),
+            ));
+            return Err(());
+        }
+
+        match token.kind {
+            TokenKind::StringLiteral => Ok(IdentifierOrString::StringNode(
+                self.parse_string_literal(token, self.source(&token)),
+            )),
+            _ => {
+                self.record_error(Diagnostic::error(
+                    SyntaxError::Expected(TokenKind::StringLiteral),
+                    Location::new(self.source_location, token.span),
+                ));
+                Err(())
+            }
+        }
+    }
+
     /// Field : Alias? Name Arguments? Directives? SelectionSet?
     fn parse_field(&mut self) -> ParseResult<Selection> {
         let start = self.index();
-        let name = self.parse_identifier()?;
+        let maybe_alias = self.parse_name_or_string_literal()?;
         let (name, alias) = if self.peek_token_kind() == TokenKind::Colon {
             let colon = self.parse_kind(TokenKind::Colon)?;
-            let alias = name;
+            let alias = match maybe_alias {
+                IdentifierOrString::Identifier(node) => node,
+                IdentifierOrString::StringNode(node) => Identifier {
+                    span: node.token.span,
+                    token: node.token,
+                    value: node.value,
+                },
+            };
             let name = {
                 match self.peek_token_kind() {
                     TokenKind::Identifier => self.parse_identifier()?,
@@ -1962,8 +1998,18 @@ impl<'a> Parser<'a> {
                 }),
             )
         } else {
-            (name, None)
+            match maybe_alias {
+                IdentifierOrString::StringNode(node) => {
+                    self.record_error(Diagnostic::error(
+                        SyntaxError::Expected(TokenKind::Identifier),
+                        Location::new(self.source_location, node.token.span),
+                    ));
+                    (self.empty_identifier(), None)
+                }
+                IdentifierOrString::Identifier(node) => (node, None),
+            }
         };
+
         let arguments = self.parse_optional_arguments()?;
         let directives = self.parse_directives()?;
         if self.peek_token_kind() == TokenKind::OpenBrace {
@@ -2389,13 +2435,9 @@ impl<'a> Parser<'a> {
         let token = self.parse_token();
         let source = self.source(&token);
         match &token.kind {
-            TokenKind::StringLiteral => {
-                let value = source[1..source.len() - 1].to_string();
-                Ok(ConstantValue::String(StringNode {
-                    token,
-                    value: value.intern(),
-                }))
-            }
+            TokenKind::StringLiteral => Ok(ConstantValue::String(
+                self.parse_string_literal(token, source),
+            )),
             TokenKind::BlockStringLiteral => {
                 let value = clean_block_string_literal(source);
                 Ok(ConstantValue::String(StringNode {
@@ -2499,6 +2541,14 @@ impl<'a> Parser<'a> {
         }
     }
 
+    fn parse_string_literal(&self, token: Token, source: &str) -> StringNode {
+        let value = source[1..source.len() - 1].to_string();
+        StringNode {
+            token,
+            value: value.intern(),
+        }
+    }
+
     /// IntValue
     /// FloatValue
     /// StringValue

compiler/crates/graphql-syntax/tests/parse_document_with_enquoted_alias.rs

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+use common::Diagnostic;
+use common::SourceLocationKey;
+use common::TextSource;
+use fixture_tests::Fixture;
+use graphql_cli::DiagnosticPrinter;
+use graphql_syntax::ParserFeatures;
+use graphql_syntax::parse_executable_with_features;
+
+pub async fn transform_fixture(fixture: &Fixture<'_>) -> Result<String, String> {
+    parse_executable_with_features(
+        fixture.content,
+        SourceLocationKey::standalone(fixture.file_name),
+        ParserFeatures {
+            allow_string_literal_alias: true,
+            ..Default::default()
+        },
+    )
+    .map(|x| format!("{:#?}", x))
+    .map_err(|diagnostics| diagnostics_to_sorted_string(fixture.content, &diagnostics))
+}
+
+// NOTE: copied from graphql-test-helpers to avoid cyclic dependency breaking Rust Analyzer
+fn diagnostics_to_sorted_string(source: &str, diagnostics: &[Diagnostic]) -> String {
+    let printer =
+        DiagnosticPrinter::new(|_| Some(TextSource::from_whole_document(source.to_string())));
+    let mut printed = diagnostics
+        .iter()
+        .map(|diagnostic| printer.diagnostic_to_string(diagnostic))
+        .collect::<Vec<_>>();
+    printed.sort();
+    printed.join("\n\n")
+}

compiler/crates/graphql-syntax/tests/parse_document_with_enquoted_alias/fixtures/enquoted_alias_with_enquoted_field.invalid.expected

@@ -0,0 +1,23 @@
+==================================== INPUT ====================================
+# expected-to-throw
+
+query EnquotedAliasWithEnquotedFieldName {
+  "alias": "field_name"
+}
+==================================== ERROR ====================================
+✖︎ Expected a non-variable identifier (e.g. 'x' or 'Foo')
+
+  enquoted_alias_with_enquoted_field.invalid.graphql:4:12
+    3 │ query EnquotedAliasWithEnquotedFieldName {
+    4 │   "alias": "field_name"
+      │            ^^^^^^^^^^^^
+    5 │ }
+
+
+✖︎ Incomplete field alias, expected non-variable identifier (e.g. 'x' or 'Foo') but found string literal (e.g. '"..."')
+
+  enquoted_alias_with_enquoted_field.invalid.graphql:4:3
+    3 │ query EnquotedAliasWithEnquotedFieldName {
+    4 │   "alias": "field_name"
+      │   ^^^^^^^^
+    5 │ }

compiler/crates/graphql-syntax/tests/parse_document_with_enquoted_alias/fixtures/enquoted_alias_with_enquoted_field.invalid.graphql

@@ -0,0 +1,5 @@
+# expected-to-throw
+
+query EnquotedAliasWithEnquotedFieldName {
+  "alias": "field_name"
+}

compiler/crates/graphql-syntax/tests/parse_document_with_enquoted_alias/fixtures/enquoted_alias_with_escape.expected

@@ -0,0 +1,77 @@
+==================================== INPUT ====================================
+query EnquotedAlias {
+  "1$ali\"as": escaped_quote_alias
+}
+==================================== OUTPUT ===================================
+ExecutableDocument {
+    span: 0:59,
+    definitions: [
+        OperationDefinition {
+            location: enquoted_alias_with_escape.graphql:0:58,
+            operation: Some(
+                (
+                    Token {
+                        span: 0:5,
+                        kind: Identifier,
+                    },
+                    Query,
+                ),
+            ),
+            name: Some(
+                Identifier {
+                    span: 6:19,
+                    token: Token {
+                        span: 6:19,
+                        kind: Identifier,
+                    },
+                    value: "EnquotedAlias",
+                },
+            ),
+            variable_definitions: None,
+            directives: [],
+            selections: List {
+                span: 20:58,
+                start: Token {
+                    span: 20:21,
+                    kind: OpenBrace,
+                },
+                items: [
+                    ScalarField {
+                        span: 24:56,
+                        alias: Some(
+                            Alias {
+                                span: 24:56,
+                                alias: Identifier {
+                                    span: 24:35,
+                                    token: Token {
+                                        span: 24:35,
+                                        kind: StringLiteral,
+                                    },
+                                    value: "1$ali\\\"as",
+                                },
+                                colon: Token {
+                                    span: 35:36,
+                                    kind: Colon,
+                                },
+                            },
+                        ),
+                        name: Identifier {
+                            span: 37:56,
+                            token: Token {
+                                span: 37:56,
+                                kind: Identifier,
+                            },
+                            value: "escaped_quote_alias",
+                        },
+                        arguments: None,
+                        directives: [],
+                    },
+                ],
+                end: Token {
+                    span: 57:58,
+                    kind: CloseBrace,
+                },
+            },
+        },
+    ],
+}

compiler/crates/graphql-syntax/tests/parse_document_with_enquoted_alias/fixtures/enquoted_alias_with_escape.graphql

@@ -0,0 +1,3 @@
+query EnquotedAlias {
+  "1$ali\"as": escaped_quote_alias
+}

compiler/crates/graphql-syntax/tests/parse_document_with_enquoted_alias/fixtures/enquoted_field_name.invalid.expected

@@ -0,0 +1,14 @@
+==================================== INPUT ====================================
+# expected-to-throw
+
+query EnquotedFieldName {
+  "field_name"
+}
+==================================== ERROR ====================================
+✖︎ Expected a non-variable identifier (e.g. 'x' or 'Foo')
+
+  enquoted_field_name.invalid.graphql:4:3
+    3 │ query EnquotedFieldName {
+    4 │   "field_name"
+      │   ^^^^^^^^^^^^
+    5 │ }

compiler/crates/graphql-syntax/tests/parse_document_with_enquoted_alias/fixtures/enquoted_field_name.invalid.graphql

@@ -0,0 +1,5 @@
+# expected-to-throw
+
+query EnquotedFieldName {
+  "field_name"
+}