Add tests

microsoft · Nov 2, 2019 · 3fa24c7 · 3fa24c7
1 parent b1b0073
commit 3fa24c7
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Showing 2 changed files with 10 additions and 3 deletions.
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -3855,7 +3855,7 @@ namespace ts {
                 }
                 if (type.flags & TypeFlags.TypeParameter || objectFlags & ObjectFlags.ClassOrInterface) {
                     if (type.flags & TypeFlags.TypeParameter && contains(context.inferTypeParameters, type)) {
-                        context.approximateLength += (symbolName(type.symbol).length + 6);
+                        context.approximateLength += 6 + (type.symbol ? symbolName(type.symbol).length : 1);
                         return createInferTypeNode(typeParameterToDeclarationWithConstraint(type as TypeParameter, context, /*constraintNode*/ undefined));
                     }
                     if (context.flags & NodeBuilderFlags.GenerateNamesForShadowedTypeParams &&
@@ -4791,7 +4791,7 @@ namespace ts {
                         return cached;
                     }
                 }
-                let result = symbolToName(type.symbol, context, SymbolFlags.Type, /*expectsIdentifier*/ true);
+                let result = type.symbol ? symbolToName(type.symbol, context, SymbolFlags.Type, /*expectsIdentifier*/ true) : createIdentifier("?");
                 if (!(result.kind & SyntaxKind.Identifier)) {
                     return createIdentifier("(Missing type parameter)");
                 }

diff --git a/tests/cases/compiler/asyncFunctionReturnType.ts b/tests/cases/compiler/asyncFunctionReturnType.ts
@@ -73,4 +73,11 @@ async function fGenericIndexedTypeForPromiseOfKProp<TObj extends Obj, K extends
 
 async function fGenericIndexedTypeForExplicitPromiseOfKProp<TObj extends Obj, K extends keyof TObj>(obj: TObj, key: K): Promise<TObj[K]> {
     return Promise.resolve<TObj[K]>(obj[key]);
-}
+}
+
+// #27711
+
+async function fGeneric<T>(x: T) {
+    return x;
+}
+const result: Promise<number> = fGeneric(undefined as Promise<number>);