From 7f64b3a82c632055e7ae1fd52c4ff754f9db5391 Mon Sep 17 00:00:00 2001
From: TypeScript Bot <ts_bot@rcavanaugh.com>
Date: Tue, 16 Feb 2021 11:25:58 -0800
Subject: [PATCH] Cherry-pick PR #42626 into release-4.2 (#42780)

Component commits:
214ef0c750 No did-you-mean-to-call error on casts
I chose to do the ad-hoc check rather than yet another tree walk.

1. It's faster to run and easier to read.
2. This error came from looking at real code. It happened twice, so I
think the best estimate for other uses that happened zero times is in
fact zero.
3. I couldn't think of other places to put the cast, given the
restrictions on `testedNode` just before the new code.

1d347785de Merge branch 'master' into no-did-you-mean-to-call-error-on-casts

Co-authored-by: Nathan Shively-Sanders <nathansa@microsoft.com>
---
 src/compiler/checker.ts                       |  5 +++-
 .../truthinessCallExpressionCoercion3.js      | 19 +++++++++++++++
 .../truthinessCallExpressionCoercion3.symbols | 24 +++++++++++++++++++
 .../truthinessCallExpressionCoercion3.types   | 23 ++++++++++++++++++
 .../truthinessCallExpressionCoercion3.ts      | 13 ++++++++++
 5 files changed, 83 insertions(+), 1 deletion(-)
 create mode 100644 tests/baselines/reference/truthinessCallExpressionCoercion3.js
 create mode 100644 tests/baselines/reference/truthinessCallExpressionCoercion3.symbols
 create mode 100644 tests/baselines/reference/truthinessCallExpressionCoercion3.types
 create mode 100644 tests/cases/compiler/truthinessCallExpressionCoercion3.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 3de21bebf7681..4baec04d9967e 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -34542,8 +34542,11 @@ namespace ts {
                 : isPropertyAccessExpression(location) ? location.name
                 : isBinaryExpression(location) && isIdentifier(location.right) ? location.right
                 : undefined;
+            const isPropertyExpressionCast = isPropertyAccessExpression(location)
+                && isParenthesizedExpression(location.expression)
+                && isAssertionExpression(location.expression.expression);
 
-            if (!testedNode) {
+            if (!testedNode || isPropertyExpressionCast) {
                 return;
             }
 
diff --git a/tests/baselines/reference/truthinessCallExpressionCoercion3.js b/tests/baselines/reference/truthinessCallExpressionCoercion3.js
new file mode 100644
index 0000000000000..a2ab27f21a2ef
--- /dev/null
+++ b/tests/baselines/reference/truthinessCallExpressionCoercion3.js
@@ -0,0 +1,19 @@
+//// [truthinessCallExpressionCoercion3.ts]
+// from #41640, based on an example in ant-design
+interface I {
+    always(): void
+}
+
+function f(result: unknown) {
+    if ((result as I).always) {
+        return result
+    }
+}
+
+
+//// [truthinessCallExpressionCoercion3.js]
+function f(result) {
+    if (result.always) {
+        return result;
+    }
+}
diff --git a/tests/baselines/reference/truthinessCallExpressionCoercion3.symbols b/tests/baselines/reference/truthinessCallExpressionCoercion3.symbols
new file mode 100644
index 0000000000000..35392c06aef0e
--- /dev/null
+++ b/tests/baselines/reference/truthinessCallExpressionCoercion3.symbols
@@ -0,0 +1,24 @@
+=== tests/cases/compiler/truthinessCallExpressionCoercion3.ts ===
+// from #41640, based on an example in ant-design
+interface I {
+>I : Symbol(I, Decl(truthinessCallExpressionCoercion3.ts, 0, 0))
+
+    always(): void
+>always : Symbol(I.always, Decl(truthinessCallExpressionCoercion3.ts, 1, 13))
+}
+
+function f(result: unknown) {
+>f : Symbol(f, Decl(truthinessCallExpressionCoercion3.ts, 3, 1))
+>result : Symbol(result, Decl(truthinessCallExpressionCoercion3.ts, 5, 11))
+
+    if ((result as I).always) {
+>(result as I).always : Symbol(I.always, Decl(truthinessCallExpressionCoercion3.ts, 1, 13))
+>result : Symbol(result, Decl(truthinessCallExpressionCoercion3.ts, 5, 11))
+>I : Symbol(I, Decl(truthinessCallExpressionCoercion3.ts, 0, 0))
+>always : Symbol(I.always, Decl(truthinessCallExpressionCoercion3.ts, 1, 13))
+
+        return result
+>result : Symbol(result, Decl(truthinessCallExpressionCoercion3.ts, 5, 11))
+    }
+}
+
diff --git a/tests/baselines/reference/truthinessCallExpressionCoercion3.types b/tests/baselines/reference/truthinessCallExpressionCoercion3.types
new file mode 100644
index 0000000000000..200ddbfa13ecc
--- /dev/null
+++ b/tests/baselines/reference/truthinessCallExpressionCoercion3.types
@@ -0,0 +1,23 @@
+=== tests/cases/compiler/truthinessCallExpressionCoercion3.ts ===
+// from #41640, based on an example in ant-design
+interface I {
+    always(): void
+>always : () => void
+}
+
+function f(result: unknown) {
+>f : (result: unknown) => unknown
+>result : unknown
+
+    if ((result as I).always) {
+>(result as I).always : () => void
+>(result as I) : I
+>result as I : I
+>result : unknown
+>always : () => void
+
+        return result
+>result : unknown
+    }
+}
+
diff --git a/tests/cases/compiler/truthinessCallExpressionCoercion3.ts b/tests/cases/compiler/truthinessCallExpressionCoercion3.ts
new file mode 100644
index 0000000000000..69f6ba8214d40
--- /dev/null
+++ b/tests/cases/compiler/truthinessCallExpressionCoercion3.ts
@@ -0,0 +1,13 @@
+// @strictNullChecks: true
+// @lib: esnext,dom
+
+// from #41640, based on an example in ant-design
+interface I {
+    always(): void
+}
+
+function f(result: unknown) {
+    if ((result as I).always) {
+        return result
+    }
+}