From 4800464ed6191d4ba8b99fb790b60aa3de6398bb Mon Sep 17 00:00:00 2001
From: Vladimir Matveev <vladima@microsoft.com>
Date: Mon, 3 Oct 2016 11:03:28 -0700
Subject: [PATCH] do not reset current flow after processing finally block if
 it was unreachable (#11310)

* do not reset current flow after processing finally block if it was unreachable

* fix tests
---
 src/compiler/binder.ts                        |  6 ++++-
 .../reference/unreachableFlowAfterFinally.js  | 27 +++++++++++++++++++
 .../unreachableFlowAfterFinally.symbols       | 20 ++++++++++++++
 .../unreachableFlowAfterFinally.types         | 22 +++++++++++++++
 .../compiler/unreachableFlowAfterFinally.ts   | 14 ++++++++++
 5 files changed, 88 insertions(+), 1 deletion(-)
 create mode 100644 tests/baselines/reference/unreachableFlowAfterFinally.js
 create mode 100644 tests/baselines/reference/unreachableFlowAfterFinally.symbols
 create mode 100644 tests/baselines/reference/unreachableFlowAfterFinally.types
 create mode 100644 tests/cases/compiler/unreachableFlowAfterFinally.ts

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index e2d31162127..2fe7d30ab56 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -964,7 +964,11 @@ namespace ts {
                 currentFlow = preTryFlow;
                 bind(node.finallyBlock);
             }
-            currentFlow = finishFlowLabel(postFinallyLabel);
+            // if try statement has finally block and flow after finally block is unreachable - keep it
+            // otherwise use whatever flow was accumulated at postFinallyLabel
+            if (!node.finallyBlock || !(currentFlow.flags & FlowFlags.Unreachable)) {
+                currentFlow = finishFlowLabel(postFinallyLabel);
+            }
         }
 
         function bindSwitchStatement(node: SwitchStatement): void {
diff --git a/tests/baselines/reference/unreachableFlowAfterFinally.js b/tests/baselines/reference/unreachableFlowAfterFinally.js
new file mode 100644
index 00000000000..97f04b219b6
--- /dev/null
+++ b/tests/baselines/reference/unreachableFlowAfterFinally.js
@@ -0,0 +1,27 @@
+//// [unreachableFlowAfterFinally.ts]
+
+function f() {
+    let x = 100;
+    try {
+        throw "WAT"
+    }
+    catch (e) {
+
+    }
+    finally {
+        return x;
+    }
+}
+
+//// [unreachableFlowAfterFinally.js]
+function f() {
+    var x = 100;
+    try {
+        throw "WAT";
+    }
+    catch (e) {
+    }
+    finally {
+        return x;
+    }
+}
diff --git a/tests/baselines/reference/unreachableFlowAfterFinally.symbols b/tests/baselines/reference/unreachableFlowAfterFinally.symbols
new file mode 100644
index 00000000000..92a5d7b06a5
--- /dev/null
+++ b/tests/baselines/reference/unreachableFlowAfterFinally.symbols
@@ -0,0 +1,20 @@
+=== tests/cases/compiler/unreachableFlowAfterFinally.ts ===
+
+function f() {
+>f : Symbol(f, Decl(unreachableFlowAfterFinally.ts, 0, 0))
+
+    let x = 100;
+>x : Symbol(x, Decl(unreachableFlowAfterFinally.ts, 2, 7))
+
+    try {
+        throw "WAT"
+    }
+    catch (e) {
+>e : Symbol(e, Decl(unreachableFlowAfterFinally.ts, 6, 11))
+
+    }
+    finally {
+        return x;
+>x : Symbol(x, Decl(unreachableFlowAfterFinally.ts, 2, 7))
+    }
+}
diff --git a/tests/baselines/reference/unreachableFlowAfterFinally.types b/tests/baselines/reference/unreachableFlowAfterFinally.types
new file mode 100644
index 00000000000..814bebfc2fd
--- /dev/null
+++ b/tests/baselines/reference/unreachableFlowAfterFinally.types
@@ -0,0 +1,22 @@
+=== tests/cases/compiler/unreachableFlowAfterFinally.ts ===
+
+function f() {
+>f : () => number
+
+    let x = 100;
+>x : number
+>100 : 100
+
+    try {
+        throw "WAT"
+>"WAT" : "WAT"
+    }
+    catch (e) {
+>e : any
+
+    }
+    finally {
+        return x;
+>x : number
+    }
+}
diff --git a/tests/cases/compiler/unreachableFlowAfterFinally.ts b/tests/cases/compiler/unreachableFlowAfterFinally.ts
new file mode 100644
index 00000000000..4a7c0944949
--- /dev/null
+++ b/tests/cases/compiler/unreachableFlowAfterFinally.ts
@@ -0,0 +1,14 @@
+// @noImplicitReturns: true
+
+function f() {
+    let x = 100;
+    try {
+        throw "WAT"
+    }
+    catch (e) {
+
+    }
+    finally {
+        return x;
+    }
+}
\ No newline at end of file