From 11eabc0946b26dfa1572cc6167e9f18dc39ed24a Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <293473+sandersn@users.noreply.github.com>
Date: Tue, 3 Apr 2018 06:23:59 -0700
Subject: [PATCH] Skip parens and non-null assertions when looking for
 this-context (#23097)

* Skip parens and ! for getting this-context of call

* Add test and improve code a bit

* Use skipOuterExpressions instead
---
 src/compiler/checker.ts                       |  9 +--
 src/compiler/utilities.ts                     |  2 +-
 .../reference/thisTypeSyntacticContext.js     | 27 ++++++++
 .../thisTypeSyntacticContext.symbols          | 52 ++++++++++++++
 .../reference/thisTypeSyntacticContext.types  | 69 +++++++++++++++++++
 .../thisType/thisTypeSyntacticContext.ts      | 13 ++++
 6 files changed, 165 insertions(+), 7 deletions(-)
 create mode 100644 tests/baselines/reference/thisTypeSyntacticContext.js
 create mode 100644 tests/baselines/reference/thisTypeSyntacticContext.symbols
 create mode 100644 tests/baselines/reference/thisTypeSyntacticContext.types
 create mode 100644 tests/cases/conformance/types/thisType/thisTypeSyntacticContext.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 1e6a16aa75f..c60f9c23029 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -17269,12 +17269,9 @@ namespace ts {
          */
         function getThisArgumentOfCall(node: CallLikeExpression): LeftHandSideExpression {
             if (node.kind === SyntaxKind.CallExpression) {
-                const callee = node.expression;
-                if (callee.kind === SyntaxKind.PropertyAccessExpression) {
-                    return (callee as PropertyAccessExpression).expression;
-                }
-                else if (callee.kind === SyntaxKind.ElementAccessExpression) {
-                    return (callee as ElementAccessExpression).expression;
+                const callee = skipOuterExpressions(node.expression);
+                if (callee.kind === SyntaxKind.PropertyAccessExpression || callee.kind === SyntaxKind.ElementAccessExpression) {
+                    return (callee as PropertyAccessExpression | ElementAccessExpression).expression;
                 }
             }
         }
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 9fba1a6610b..b8737960f47 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -2022,7 +2022,7 @@ namespace ts {
     export function skipParentheses(node: Node): Node;
     export function skipParentheses(node: Node): Node {
         while (node.kind === SyntaxKind.ParenthesizedExpression) {
-            node = (<ParenthesizedExpression>node).expression;
+            node = (node as ParenthesizedExpression).expression;
         }
 
         return node;
diff --git a/tests/baselines/reference/thisTypeSyntacticContext.js b/tests/baselines/reference/thisTypeSyntacticContext.js
new file mode 100644
index 00000000000..8a67842efbd
--- /dev/null
+++ b/tests/baselines/reference/thisTypeSyntacticContext.js
@@ -0,0 +1,27 @@
+//// [thisTypeSyntacticContext.ts]
+function f(this: { n: number }) {
+}
+
+const o: { n: number, test?: (this: { n: number }) => void } = { n: 1 }
+o.test = f
+
+o.test();
+o!.test();
+o.test!();
+o.test!!!();
+(o.test!)();
+(o.test)();
+
+
+
+//// [thisTypeSyntacticContext.js]
+function f() {
+}
+var o = { n: 1 };
+o.test = f;
+o.test();
+o.test();
+o.test();
+o.test();
+(o.test)();
+(o.test)();
diff --git a/tests/baselines/reference/thisTypeSyntacticContext.symbols b/tests/baselines/reference/thisTypeSyntacticContext.symbols
new file mode 100644
index 00000000000..07ea27bbff2
--- /dev/null
+++ b/tests/baselines/reference/thisTypeSyntacticContext.symbols
@@ -0,0 +1,52 @@
+=== tests/cases/conformance/types/thisType/thisTypeSyntacticContext.ts ===
+function f(this: { n: number }) {
+>f : Symbol(f, Decl(thisTypeSyntacticContext.ts, 0, 0))
+>this : Symbol(this, Decl(thisTypeSyntacticContext.ts, 0, 11))
+>n : Symbol(n, Decl(thisTypeSyntacticContext.ts, 0, 18))
+}
+
+const o: { n: number, test?: (this: { n: number }) => void } = { n: 1 }
+>o : Symbol(o, Decl(thisTypeSyntacticContext.ts, 3, 5))
+>n : Symbol(n, Decl(thisTypeSyntacticContext.ts, 3, 10))
+>test : Symbol(test, Decl(thisTypeSyntacticContext.ts, 3, 21))
+>this : Symbol(this, Decl(thisTypeSyntacticContext.ts, 3, 30))
+>n : Symbol(n, Decl(thisTypeSyntacticContext.ts, 3, 37))
+>n : Symbol(n, Decl(thisTypeSyntacticContext.ts, 3, 64))
+
+o.test = f
+>o.test : Symbol(test, Decl(thisTypeSyntacticContext.ts, 3, 21))
+>o : Symbol(o, Decl(thisTypeSyntacticContext.ts, 3, 5))
+>test : Symbol(test, Decl(thisTypeSyntacticContext.ts, 3, 21))
+>f : Symbol(f, Decl(thisTypeSyntacticContext.ts, 0, 0))
+
+o.test();
+>o.test : Symbol(test, Decl(thisTypeSyntacticContext.ts, 3, 21))
+>o : Symbol(o, Decl(thisTypeSyntacticContext.ts, 3, 5))
+>test : Symbol(test, Decl(thisTypeSyntacticContext.ts, 3, 21))
+
+o!.test();
+>o!.test : Symbol(test, Decl(thisTypeSyntacticContext.ts, 3, 21))
+>o : Symbol(o, Decl(thisTypeSyntacticContext.ts, 3, 5))
+>test : Symbol(test, Decl(thisTypeSyntacticContext.ts, 3, 21))
+
+o.test!();
+>o.test : Symbol(test, Decl(thisTypeSyntacticContext.ts, 3, 21))
+>o : Symbol(o, Decl(thisTypeSyntacticContext.ts, 3, 5))
+>test : Symbol(test, Decl(thisTypeSyntacticContext.ts, 3, 21))
+
+o.test!!!();
+>o.test : Symbol(test, Decl(thisTypeSyntacticContext.ts, 3, 21))
+>o : Symbol(o, Decl(thisTypeSyntacticContext.ts, 3, 5))
+>test : Symbol(test, Decl(thisTypeSyntacticContext.ts, 3, 21))
+
+(o.test!)();
+>o.test : Symbol(test, Decl(thisTypeSyntacticContext.ts, 3, 21))
+>o : Symbol(o, Decl(thisTypeSyntacticContext.ts, 3, 5))
+>test : Symbol(test, Decl(thisTypeSyntacticContext.ts, 3, 21))
+
+(o.test)();
+>o.test : Symbol(test, Decl(thisTypeSyntacticContext.ts, 3, 21))
+>o : Symbol(o, Decl(thisTypeSyntacticContext.ts, 3, 5))
+>test : Symbol(test, Decl(thisTypeSyntacticContext.ts, 3, 21))
+
+
diff --git a/tests/baselines/reference/thisTypeSyntacticContext.types b/tests/baselines/reference/thisTypeSyntacticContext.types
new file mode 100644
index 00000000000..e6996b0eb92
--- /dev/null
+++ b/tests/baselines/reference/thisTypeSyntacticContext.types
@@ -0,0 +1,69 @@
+=== tests/cases/conformance/types/thisType/thisTypeSyntacticContext.ts ===
+function f(this: { n: number }) {
+>f : (this: { n: number; }) => void
+>this : { n: number; }
+>n : number
+}
+
+const o: { n: number, test?: (this: { n: number }) => void } = { n: 1 }
+>o : { n: number; test?: (this: { n: number; }) => void; }
+>n : number
+>test : (this: { n: number; }) => void
+>this : { n: number; }
+>n : number
+>{ n: 1 } : { n: number; }
+>n : number
+>1 : 1
+
+o.test = f
+>o.test = f : (this: { n: number; }) => void
+>o.test : (this: { n: number; }) => void
+>o : { n: number; test?: (this: { n: number; }) => void; }
+>test : (this: { n: number; }) => void
+>f : (this: { n: number; }) => void
+
+o.test();
+>o.test() : void
+>o.test : (this: { n: number; }) => void
+>o : { n: number; test?: (this: { n: number; }) => void; }
+>test : (this: { n: number; }) => void
+
+o!.test();
+>o!.test() : void
+>o!.test : (this: { n: number; }) => void
+>o! : { n: number; test?: (this: { n: number; }) => void; }
+>o : { n: number; test?: (this: { n: number; }) => void; }
+>test : (this: { n: number; }) => void
+
+o.test!();
+>o.test!() : void
+>o.test! : (this: { n: number; }) => void
+>o.test : (this: { n: number; }) => void
+>o : { n: number; test?: (this: { n: number; }) => void; }
+>test : (this: { n: number; }) => void
+
+o.test!!!();
+>o.test!!!() : void
+>o.test!!! : (this: { n: number; }) => void
+>o.test!! : (this: { n: number; }) => void
+>o.test! : (this: { n: number; }) => void
+>o.test : (this: { n: number; }) => void
+>o : { n: number; test?: (this: { n: number; }) => void; }
+>test : (this: { n: number; }) => void
+
+(o.test!)();
+>(o.test!)() : void
+>(o.test!) : (this: { n: number; }) => void
+>o.test! : (this: { n: number; }) => void
+>o.test : (this: { n: number; }) => void
+>o : { n: number; test?: (this: { n: number; }) => void; }
+>test : (this: { n: number; }) => void
+
+(o.test)();
+>(o.test)() : void
+>(o.test) : (this: { n: number; }) => void
+>o.test : (this: { n: number; }) => void
+>o : { n: number; test?: (this: { n: number; }) => void; }
+>test : (this: { n: number; }) => void
+
+
diff --git a/tests/cases/conformance/types/thisType/thisTypeSyntacticContext.ts b/tests/cases/conformance/types/thisType/thisTypeSyntacticContext.ts
new file mode 100644
index 00000000000..8daa1986697
--- /dev/null
+++ b/tests/cases/conformance/types/thisType/thisTypeSyntacticContext.ts
@@ -0,0 +1,13 @@
+function f(this: { n: number }) {
+}
+
+const o: { n: number, test?: (this: { n: number }) => void } = { n: 1 }
+o.test = f
+
+o.test();
+o!.test();
+o.test!();
+o.test!!!();
+(o.test!)();
+(o.test)();
+