From 6f72e24544928f1ea9fa50a9be0c6a73ba92e070 Mon Sep 17 00:00:00 2001
From: Wesley Wigham <wewigham@microsoft.com>
Date: Tue, 21 May 2024 13:44:35 -0700
Subject: [PATCH] Fix elided var handling in declaration emit visibility checks
 (#58605)

Co-authored-by: TypeScript Bot <typescriptbot@microsoft.com>
---
 src/compiler/checker.ts                          | 11 +++++++++--
 .../declarationEmitInvalidExport.errors.txt      |  5 ++++-
 .../reference/declarationEmitInvalidExport.js    |  4 ----
 .../declarationEmitVarInElidedBlock.errors.txt   | 10 ++++++++++
 .../declarationEmitVarInElidedBlock.symbols      | 11 +++++++++++
 .../declarationEmitVarInElidedBlock.types        | 16 ++++++++++++++++
 .../compiler/declarationEmitVarInElidedBlock.ts  |  6 ++++++
 7 files changed, 56 insertions(+), 7 deletions(-)
 create mode 100644 tests/baselines/reference/declarationEmitVarInElidedBlock.errors.txt
 create mode 100644 tests/baselines/reference/declarationEmitVarInElidedBlock.symbols
 create mode 100644 tests/baselines/reference/declarationEmitVarInElidedBlock.types
 create mode 100644 tests/cases/compiler/declarationEmitVarInElidedBlock.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index a4020504f9c..df8026b71ec 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5862,9 +5862,16 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
             return { accessibility: SymbolAccessibility.Accessible };
         }
 
+        if (!symbol) {
+            return {
+                accessibility: SymbolAccessibility.NotResolved,
+                errorSymbolName: getTextOfNode(firstIdentifier),
+                errorNode: firstIdentifier,
+            };
+        }
         // Verify if the symbol is accessible
-        return (symbol && hasVisibleDeclarations(symbol, shouldComputeAliasToMakeVisible)) || {
-            accessibility: SymbolAccessibility.NotResolved,
+        return hasVisibleDeclarations(symbol, shouldComputeAliasToMakeVisible) || {
+            accessibility: SymbolAccessibility.NotAccessible,
             errorSymbolName: getTextOfNode(firstIdentifier),
             errorNode: firstIdentifier,
         };
diff --git a/tests/baselines/reference/declarationEmitInvalidExport.errors.txt b/tests/baselines/reference/declarationEmitInvalidExport.errors.txt
index 781c383b958..afd6881f3be 100644
--- a/tests/baselines/reference/declarationEmitInvalidExport.errors.txt
+++ b/tests/baselines/reference/declarationEmitInvalidExport.errors.txt
@@ -1,11 +1,14 @@
+declarationEmitInvalidExport.ts(4,30): error TS4081: Exported type alias 'MyClass' has or is using private name 'myClass'.
 declarationEmitInvalidExport.ts(5,1): error TS1128: Declaration or statement expected.
 
 
-==== declarationEmitInvalidExport.ts (1 errors) ====
+==== declarationEmitInvalidExport.ts (2 errors) ====
     if (false) {
       export var myClass = 0;
     }
     export type MyClass = typeof myClass;
+                                 ~~~~~~~
+!!! error TS4081: Exported type alias 'MyClass' has or is using private name 'myClass'.
     }
     ~
 !!! error TS1128: Declaration or statement expected.
diff --git a/tests/baselines/reference/declarationEmitInvalidExport.js b/tests/baselines/reference/declarationEmitInvalidExport.js
index aa91414f494..77fade49af2 100644
--- a/tests/baselines/reference/declarationEmitInvalidExport.js
+++ b/tests/baselines/reference/declarationEmitInvalidExport.js
@@ -14,7 +14,3 @@ Object.defineProperty(exports, "__esModule", { value: true });
 if (false) {
     exports.myClass = 0;
 }
-
-
-//// [declarationEmitInvalidExport.d.ts]
-export type MyClass = typeof myClass;
diff --git a/tests/baselines/reference/declarationEmitVarInElidedBlock.errors.txt b/tests/baselines/reference/declarationEmitVarInElidedBlock.errors.txt
new file mode 100644
index 00000000000..28fae144d2d
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitVarInElidedBlock.errors.txt
@@ -0,0 +1,10 @@
+declarationEmitVarInElidedBlock.ts(4,22): error TS4025: Exported variable 'b' has or is using private name 'a'.
+
+
+==== declarationEmitVarInElidedBlock.ts (1 errors) ====
+    {
+        var a = "";
+    }
+    export let b: typeof a;
+                         ~
+!!! error TS4025: Exported variable 'b' has or is using private name 'a'.
\ No newline at end of file
diff --git a/tests/baselines/reference/declarationEmitVarInElidedBlock.symbols b/tests/baselines/reference/declarationEmitVarInElidedBlock.symbols
new file mode 100644
index 00000000000..c8566c47cb6
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitVarInElidedBlock.symbols
@@ -0,0 +1,11 @@
+//// [tests/cases/compiler/declarationEmitVarInElidedBlock.ts] ////
+
+=== declarationEmitVarInElidedBlock.ts ===
+{
+    var a = "";
+>a : Symbol(a, Decl(declarationEmitVarInElidedBlock.ts, 1, 7))
+}
+export let b: typeof a;
+>b : Symbol(b, Decl(declarationEmitVarInElidedBlock.ts, 3, 10))
+>a : Symbol(a, Decl(declarationEmitVarInElidedBlock.ts, 1, 7))
+
diff --git a/tests/baselines/reference/declarationEmitVarInElidedBlock.types b/tests/baselines/reference/declarationEmitVarInElidedBlock.types
new file mode 100644
index 00000000000..b814ae55601
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitVarInElidedBlock.types
@@ -0,0 +1,16 @@
+//// [tests/cases/compiler/declarationEmitVarInElidedBlock.ts] ////
+
+=== declarationEmitVarInElidedBlock.ts ===
+{
+    var a = "";
+>a : string
+>  : ^^^^^^
+>"" : ""
+>   : ^^
+}
+export let b: typeof a;
+>b : string
+>  : ^^^^^^
+>a : string
+>  : ^^^^^^
+
diff --git a/tests/cases/compiler/declarationEmitVarInElidedBlock.ts b/tests/cases/compiler/declarationEmitVarInElidedBlock.ts
new file mode 100644
index 00000000000..76e62472c5f
--- /dev/null
+++ b/tests/cases/compiler/declarationEmitVarInElidedBlock.ts
@@ -0,0 +1,6 @@
+// @declaration: true
+// @emitDeclarationOnly: true
+{
+    var a = "";
+}
+export let b: typeof a;
\ No newline at end of file