From f41b7b59ce8919702baff6ab7caf4363a001af60 Mon Sep 17 00:00:00 2001
From: Andrew Branch <andrewbranch@users.noreply.github.com>
Date: Thu, 17 Oct 2019 10:54:01 -0700
Subject: [PATCH] Fix quick info for methods whose contextual type is a mapped
 type property (#33930)

---
 src/services/symbolDisplay.ts                       | 2 +-
 tests/cases/fourslash/quickInfoMappedTypeMethods.ts | 9 +++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)
 create mode 100644 tests/cases/fourslash/quickInfoMappedTypeMethods.ts

diff --git a/src/services/symbolDisplay.ts b/src/services/symbolDisplay.ts
index 0dc540dcaca..faff3620d62 100644
--- a/src/services/symbolDisplay.ts
+++ b/src/services/symbolDisplay.ts
@@ -237,7 +237,7 @@ namespace ts.SymbolDisplay {
                 // get the signature from the declaration and write it
                 const functionDeclaration = <FunctionLike>location.parent;
                 // Use function declaration to write the signatures only if the symbol corresponding to this declaration
-                const locationIsSymbolDeclaration = find(symbol.declarations, declaration =>
+                const locationIsSymbolDeclaration = symbol.declarations && find(symbol.declarations, declaration =>
                     declaration === (location.kind === SyntaxKind.ConstructorKeyword ? functionDeclaration.parent : functionDeclaration));
 
                 if (locationIsSymbolDeclaration) {
diff --git a/tests/cases/fourslash/quickInfoMappedTypeMethods.ts b/tests/cases/fourslash/quickInfoMappedTypeMethods.ts
new file mode 100644
index 00000000000..8107775b9e4
--- /dev/null
+++ b/tests/cases/fourslash/quickInfoMappedTypeMethods.ts
@@ -0,0 +1,9 @@
+/// <reference path="fourslash.ts" />
+// https://github.com/microsoft/TypeScript/issues/32983
+
+////type M = { [K in 'one']: any };
+////const x: M = {
+////  /**/one() {}
+////}
+
+verify.quickInfoAt("", "(property) one: any");