Merge pull request #24 from timocov/fix23_wrong_generic_type

Author: timocov

src/transformer.ts

@@ -289,6 +289,10 @@ function createTransformerFactory(program: ts.Program, options?: Partial<RenameO
 			const symbol = type.getSymbol();
 			const propertySymbol = typeChecker.getPropertyOfType(type, typePropertyName);
 
+			if (type.flags & ts.TypeFlags.IndexedAccess) {
+				return isTypePropertyExternal(typeChecker.getApparentType(type), typePropertyName);
+			}
+
 			if (type.flags & ts.TypeFlags.Object) {
 				const objectType = type as ts.ObjectType;
 				// treat any tuple property as "external"

tests/test-cases/indexed-generic-as-returned-type/input.ts

@@ -0,0 +1,26 @@
+export interface Ohlc {
+	open: number;
+	high: number;
+	low: number;
+	close: number;
+}
+
+interface BarValueByType {
+	Bar: Ohlc;
+	Line: number;
+}
+
+type SeriesType = keyof BarValueByType;
+
+function getBarValue<T extends SeriesType>(value: number, seriesType: T): BarValueByType[T] {
+	if (seriesType === 'Bar') {
+		return {
+			open: value,
+			high: value,
+			low: value,
+			close: value,
+		} as BarValueByType[T];
+	} else {
+		return value as BarValueByType[T];
+	}
+}

tests/test-cases/indexed-generic-as-returned-type/output.js

@@ -0,0 +1,15 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+function getBarValue(value, seriesType) {
+    if (seriesType === 'Bar') {
+        return {
+            open: value,
+            high: value,
+            low: value,
+            close: value,
+        };
+    }
+    else {
+        return value;
+    }
+}