From 90667e104df18bce0e0457d90393b54f2b9a9730 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Mon, 13 May 2019 12:42:33 -0700
Subject: [PATCH 1/3] Remove this-parameter filtering in statement completion

---
 src/compiler/checker.ts | 20 +-------------------
 1 file changed, 1 insertion(+), 19 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 64834befee1c8..b730f382db3dd 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -20386,25 +20386,7 @@ namespace ts {
         }
 
         function isValidPropertyAccessForCompletions(node: PropertyAccessExpression | ImportTypeNode | QualifiedName, type: Type, property: Symbol): boolean {
-            return isValidPropertyAccessWithType(node, node.kind === SyntaxKind.PropertyAccessExpression && node.expression.kind === SyntaxKind.SuperKeyword, property.escapedName, type)
-                && (!(property.flags & SymbolFlags.Method) || isValidMethodAccess(property, type));
-        }
-        function isValidMethodAccess(method: Symbol, actualThisType: Type): boolean {
-            const propType = getTypeOfPropertyOfType(actualThisType, method.escapedName)!;
-            const signatures = getSignaturesOfType(getNonNullableType(propType), SignatureKind.Call);
-            Debug.assert(signatures.length !== 0);
-            return signatures.some(sig => {
-                const signatureThisType = getThisTypeOfSignature(sig);
-                return !signatureThisType || isTypeAssignableTo(actualThisType, getInstantiatedSignatureThisType(sig, signatureThisType, actualThisType));
-            });
-        }
-        function getInstantiatedSignatureThisType(sig: Signature, signatureThisType: Type, actualThisType: Type): Type {
-            if (!sig.typeParameters) {
-                return signatureThisType;
-            }
-            const context = createInferenceContext(sig.typeParameters, sig, InferenceFlags.None);
-            inferTypes(context.inferences, actualThisType, signatureThisType);
-            return instantiateType(signatureThisType, createSignatureTypeMapper(sig, getInferredTypes(context)));
+            return isValidPropertyAccessWithType(node, node.kind === SyntaxKind.PropertyAccessExpression && node.expression.kind === SyntaxKind.SuperKeyword, property.escapedName, type);
         }
 
         function isValidPropertyAccessWithType(

From a65f35b5fb4c1bc0d56724258a051b7e6f85bfce Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Mon, 13 May 2019 12:42:44 -0700
Subject: [PATCH 2/3] Remove fourslash test

---
 .../completionsMethodWithThisParameter.ts     | 20 -------------------
 1 file changed, 20 deletions(-)
 delete mode 100644 tests/cases/fourslash/completionsMethodWithThisParameter.ts

diff --git a/tests/cases/fourslash/completionsMethodWithThisParameter.ts b/tests/cases/fourslash/completionsMethodWithThisParameter.ts
deleted file mode 100644
index d746f3626dc08..0000000000000
--- a/tests/cases/fourslash/completionsMethodWithThisParameter.ts
+++ /dev/null
@@ -1,20 +0,0 @@
-/// <reference path='fourslash.ts'/>
-
-////class A<T> {
-////    value: T; // Make the type parameter actually matter
-////    ms(this: A<string>) {}
-////    mo(this: A<{}>) {}
-////    mt(this: A<T>) {}
-////    mp<P>(this: A<P>) {}
-////    mps<P extends string>(this: A<P>) {}
-////}
-////
-////const s = new A<string>();
-////const n = new A<number>();
-////s./*s*/;
-////n./*n*/;
-
-verify.completions(
-    { marker: "s", exact: ["value", "ms", "mo", "mt", "mp", "mps"] },
-    { marker: "n", exact: ["value", "mo", "mt", "mp"] },
-);

From d2923460e967d9bd58057ce1570e24e62c08c62b Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Mon, 13 May 2019 16:34:09 -0700
Subject: [PATCH 3/3] Add comment providing context on the change

---
 src/compiler/checker.ts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index b730f382db3dd..cdd873cd0bc0f 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -20387,6 +20387,7 @@ namespace ts {
 
         function isValidPropertyAccessForCompletions(node: PropertyAccessExpression | ImportTypeNode | QualifiedName, type: Type, property: Symbol): boolean {
             return isValidPropertyAccessWithType(node, node.kind === SyntaxKind.PropertyAccessExpression && node.expression.kind === SyntaxKind.SuperKeyword, property.escapedName, type);
+            // Previously we validated the 'this' type of methods but this adversely affected performance. See #31377 for more context.
         }
 
         function isValidPropertyAccessWithType(