Only add unnecessary-await suggestion on await expressions (microsoft#32754)

andrewbranch · web-flow · commit 984956afec35 · 2019-08-07T11:27:36.000-07:00
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -24037,7 +24037,11 @@ namespace ts {
             }
 
             const operandType = checkExpression(node.expression);
-            return checkAwaitedType(operandType, node, Diagnostics.Type_of_await_operand_must_either_be_a_valid_promise_or_must_not_contain_a_callable_then_member);
+            const awaitedType = checkAwaitedType(operandType, node, Diagnostics.Type_of_await_operand_must_either_be_a_valid_promise_or_must_not_contain_a_callable_then_member);
+            if (awaitedType === operandType && awaitedType !== errorType && !(operandType.flags & TypeFlags.AnyOrUnknown)) {
+                addErrorOrSuggestion(/*isError*/ false, createDiagnosticForNode(node, Diagnostics.await_has_no_effect_on_the_type_of_this_expression));
+            }
+            return awaitedType;
         }
 
         function checkPrefixUnaryExpression(node: PrefixUnaryExpression): Type {
@@ -26537,9 +26541,6 @@ namespace ts {
          */
         function checkAwaitedType(type: Type, errorNode: Node, diagnosticMessage: DiagnosticMessage, arg0?: string | number): Type {
             const awaitedType = getAwaitedType(type, errorNode, diagnosticMessage, arg0);
-            if (awaitedType === type && !(type.flags & TypeFlags.AnyOrUnknown)) {
-                addErrorOrSuggestion(/*isError*/ false, createDiagnosticForNode(errorNode, Diagnostics.await_has_no_effect_on_the_type_of_this_expression));
-            }
             return awaitedType || errorType;
         }
 
diff --git a/tests/cases/fourslash/codeFixRemoveUnnecessaryAwait_notAvailableOnReturn.ts b/tests/cases/fourslash/codeFixRemoveUnnecessaryAwait_notAvailableOnReturn.ts
@@ -0,0 +1,8 @@
+/// <reference path="fourslash.ts" />
+
+// @target: esnext
+////async function fn(): Promise<number> {
+////  return 0;
+////}
+
+verify.getSuggestionDiagnostics([]);

Original file line number	Diff line number	Diff line change
`@@ -24037,7 +24037,11 @@ namespace ts {`
`24037`	`24037`	`}`
`24038`	`24038`
`24039`	`24039`	`const operandType = checkExpression(node.expression);`
`24040`		`- return checkAwaitedType(operandType, node, Diagnostics.Type_of_await_operand_must_either_be_a_valid_promise_or_must_not_contain_a_callable_then_member);`
	`24040`	`+ const awaitedType = checkAwaitedType(operandType, node, Diagnostics.Type_of_await_operand_must_either_be_a_valid_promise_or_must_not_contain_a_callable_then_member);`
	`24041`	`+ if (awaitedType === operandType && awaitedType !== errorType && !(operandType.flags & TypeFlags.AnyOrUnknown)) {`
	`24042`	`+ addErrorOrSuggestion(/isError/ false, createDiagnosticForNode(node, Diagnostics.await_has_no_effect_on_the_type_of_this_expression));`
	`24043`	`+ }`
	`24044`	`+ return awaitedType;`
`24041`	`24045`	`}`
`24042`	`24046`
`24043`	`24047`	`function checkPrefixUnaryExpression(node: PrefixUnaryExpression): Type {`
`@@ -26537,9 +26541,6 @@ namespace ts {`
`26537`	`26541`	`*/`
`26538`	`26542`	`function checkAwaitedType(type: Type, errorNode: Node, diagnosticMessage: DiagnosticMessage, arg0?: string \| number): Type {`
`26539`	`26543`	`const awaitedType = getAwaitedType(type, errorNode, diagnosticMessage, arg0);`
`26540`		`- if (awaitedType === type && !(type.flags & TypeFlags.AnyOrUnknown)) {`
`26541`		`- addErrorOrSuggestion(/isError/ false, createDiagnosticForNode(errorNode, Diagnostics.await_has_no_effect_on_the_type_of_this_expression));`
`26542`		`- }`
`26543`	`26544`	`return awaitedType \|\| errorType;`
`26544`	`26545`	`}`
`26545`	`26546`