From 0c1730a21871762c392f8d6862adfc1005743edd Mon Sep 17 00:00:00 2001
From: Mohamed Hegazy <mhegazy@microsoft.com>
Date: Tue, 17 Oct 2017 16:51:22 -0700
Subject: [PATCH] Fix #19257: Ensure a generated signature has a return type
 (#19264)

* Fix #19257: Ensure a generated signature has a return type

* Ensure generated properties have types

* Use the same context for multiple inferences to the same property access
---
 src/services/codefixes/inferFromUsage.ts          |  6 +++---
 .../cases/fourslash/codeFixInferFromUsageCall.ts  |  8 ++++++++
 .../codeFixInferFromUsagePropertyAccess.ts        | 15 +++++++++++++++
 3 files changed, 26 insertions(+), 3 deletions(-)
 create mode 100644 tests/cases/fourslash/codeFixInferFromUsageCall.ts
 create mode 100644 tests/cases/fourslash/codeFixInferFromUsagePropertyAccess.ts

diff --git a/src/services/codefixes/inferFromUsage.ts b/src/services/codefixes/inferFromUsage.ts
index 046eb915c1..b952cc5a98 100644
--- a/src/services/codefixes/inferFromUsage.ts
+++ b/src/services/codefixes/inferFromUsage.ts
@@ -521,7 +521,7 @@ namespace ts.codefix {
             if (!usageContext.properties) {
                 usageContext.properties = createUnderscoreEscapedMap<UsageContext>();
             }
-            const propertyUsageContext = {};
+            const propertyUsageContext = usageContext.properties.get(name) || { };
             inferTypeFromContext(parent, checker, propertyUsageContext);
             usageContext.properties.set(name, propertyUsageContext);
         }
@@ -575,7 +575,7 @@ namespace ts.codefix {
                 if (usageContext.properties) {
                     usageContext.properties.forEach((context, name) => {
                         const symbol = checker.createSymbol(SymbolFlags.Property, name);
-                        symbol.type = getTypeFromUsageContext(context, checker);
+                        symbol.type = getTypeFromUsageContext(context, checker) || checker.getAnyType();
                         members.set(name, symbol);
                     });
                 }
@@ -636,7 +636,7 @@ namespace ts.codefix {
                 symbol.type = checker.getWidenedType(checker.getBaseTypeOfLiteralType(callContext.argumentTypes[i]));
                 parameters.push(symbol);
             }
-            const returnType = getTypeFromUsageContext(callContext.returnType, checker);
+            const returnType = getTypeFromUsageContext(callContext.returnType, checker) || checker.getVoidType();
             return checker.createSignature(/*declaration*/ undefined, /*typeParameters*/ undefined, /*thisParameter*/ undefined, parameters, returnType, /*typePredicate*/ undefined, callContext.argumentTypes.length, /*hasRestParameter*/ false, /*hasLiteralTypes*/ false);
         }
 
diff --git a/tests/cases/fourslash/codeFixInferFromUsageCall.ts b/tests/cases/fourslash/codeFixInferFromUsageCall.ts
new file mode 100644
index 0000000000..e74b6faf7d
--- /dev/null
+++ b/tests/cases/fourslash/codeFixInferFromUsageCall.ts
@@ -0,0 +1,8 @@
+/// <reference path='fourslash.ts' />
+
+// @noImplicitAny: true
+////function wat([|b |]) {
+////    b();
+////}
+
+verify.rangeAfterCodeFix("b: () => void");
\ No newline at end of file
diff --git a/tests/cases/fourslash/codeFixInferFromUsagePropertyAccess.ts b/tests/cases/fourslash/codeFixInferFromUsagePropertyAccess.ts
new file mode 100644
index 0000000000..c8b85ee11e
--- /dev/null
+++ b/tests/cases/fourslash/codeFixInferFromUsagePropertyAccess.ts
@@ -0,0 +1,15 @@
+/// <reference path='fourslash.ts' />
+
+// @noImplicitAny: true
+////function foo([|a, m, x |]) {
+////    a.b.c;
+////
+////    var numeric = 0;
+////    numeric = m.n();
+////
+////    x.y.z
+////    x.y.z.push(0);
+////    return x.y.z
+////}
+
+verify.rangeAfterCodeFix("a: { b: { c: any; }; }, m: { n: () => number; }, x: { y: { z: number[]; }; }", /*includeWhiteSpace*/ undefined, /*errorCode*/ undefined, /*index*/0);
\ No newline at end of file