fix: permit string/number literal in union type

Troy Tae · Troy Tae · commit a5cda4633bab · 2019-09-18T16:19:18.000+09:00
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -32797,7 +32797,7 @@ namespace ts {
                         typeToString(node.type ? getTypeFromTypeNode(node.type) : anyType));
                 }
 
-                if (type.flags & TypeFlags.Union && allTypesAssignableToKind(type, TypeFlags.StringLiteral, /*strict*/ true)) {
+                if (type.flags & TypeFlags.Union && allTypesAssignableToKind(type, TypeFlags.StringOrNumberLiteral, /*strict*/ true)) {
                     return grammarErrorOnNode(parameter.name,
                         Diagnostics.An_index_signature_parameter_type_cannot_be_a_union_type_Consider_using_a_mapped_object_type_instead);
                 }

Original file line number	Diff line number	Diff line change
`@@ -32797,7 +32797,7 @@ namespace ts {`
`32797`	`32797`	`typeToString(node.type ? getTypeFromTypeNode(node.type) : anyType));`
`32798`	`32798`	`}`
`32799`	`32799`
`32800`		`- if (type.flags & TypeFlags.Union && allTypesAssignableToKind(type, TypeFlags.StringLiteral, /strict/ true)) {`
	`32800`	`+ if (type.flags & TypeFlags.Union && allTypesAssignableToKind(type, TypeFlags.StringOrNumberLiteral, /strict/ true)) {`
`32801`	`32801`	`return grammarErrorOnNode(parameter.name,`
`32802`	`32802`	`Diagnostics.An_index_signature_parameter_type_cannot_be_a_union_type_Consider_using_a_mapped_object_type_instead);`
`32803`	`32803`	`}`