Keep parentheses around compound type in table indexer

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fixed handling of floor division (`//`) syntax when only Luau FFlag is enabled
 - Fixed missing space when table is inside of Luau interpolated string expression (`{{` is invalid syntax)
 - The CLI tool will now only write files if the contents differ, and not modify if no change (#827)
+- Fixed parentheses around a Luau compound type inside of a type table indexer being removed causing a syntax error (#828)
 
 ## [0.19.1] - 2023-11-15
 

src/formatters/luau.rs

@@ -183,6 +183,9 @@ struct TypeInfoContext {
     // Foo<(string), (number)>
     // we should NOT remove these parentheses are they may correspond to single-type type packs
     within_generic: bool,
+    /// A TypeInfo in a table indexer
+    /// we should NOT remove parentheses around a compound type [("foo" | "bar")]: string
+    within_table_indexer: bool,
 
     /// A TypeInfo part of a union/intersection operation
     /// If its a mixed composite type, then we should not remove excess parentheses. e.g.
@@ -202,6 +205,7 @@ impl TypeInfoContext {
             within_optional: false,
             within_variadic: false,
             within_generic: false,
+            within_table_indexer: false,
             contains_union: false,
             contains_intersect: false,
         }
@@ -228,6 +232,13 @@ impl TypeInfoContext {
         }
     }
 
+    fn mark_within_table_indexer(self) -> TypeInfoContext {
+        Self {
+            within_table_indexer: true,
+            ..self
+        }
+    }
+
     fn mark_contains_union(self) -> TypeInfoContext {
         Self {
             contains_union: true,
@@ -254,12 +265,18 @@ fn keep_parentheses(internal_type: &TypeInfo, context: TypeInfoContext) -> bool
             true
         }
         TypeInfo::Union { .. } | TypeInfo::Optional { .. }
-            if context.within_optional || context.within_variadic || context.contains_intersect =>
+            if context.within_optional
+                || context.within_variadic
+                || context.within_table_indexer
+                || context.contains_intersect =>
         {
             true
         }
         TypeInfo::Intersection { .. }
-            if context.within_optional || context.within_variadic || context.contains_union =>
+            if context.within_optional
+                || context.within_variadic
+                || context.within_table_indexer
+                || context.contains_union =>
         {
             true
         }
@@ -876,7 +893,12 @@ pub fn format_type_field_key(
         TypeFieldKey::IndexSignature { brackets, inner } => TypeFieldKey::IndexSignature {
             brackets: format_contained_span(ctx, brackets, shape)
                 .update_leading_trivia(leading_trivia),
-            inner: format_type_info(ctx, inner, shape + 1), // 1 = "["
+            inner: format_type_info_internal(
+                ctx,
+                inner,
+                TypeInfoContext::new().mark_within_table_indexer(),
+                shape + 1,
+            ), // 1 = "["
         },
         other => panic!("unknown node {:?}", other),
     }

tests/inputs-luau/types_parentheses_table_indexer.lua

@@ -0,0 +1,4 @@
+--- https://github.com/JohnnyMorganz/StyLua/issues/828
+type foo = {
+	[("bar" | "baz")]: any,
+}

tests/snapshots/tests__luau@types_parentheses_table_indexer.lua.snap

@@ -0,0 +1,10 @@
+---
+source: tests/tests.rs
+expression: format(&contents)
+input_file: tests/inputs-luau/types_parentheses_table_indexer.lua
+---
+--- https://github.com/JohnnyMorganz/StyLua/issues/828
+type foo = {
+	[("bar" | "baz")]: any,
+}
+