do not reset current flow after processing finally block if it was unreachable (microsoft#11310)

vladima · web-flow · commit 4800464ed619 · 2016-10-03T11:03:28.000-07:00
* do not reset current flow after processing finally block if it was unreachable

* fix tests
diff --git 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
@@ -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
@@ -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
@@ -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
@@ -0,0 +1,14 @@
+// @noImplicitReturns: true
+
+function f() {
+    let x = 100;
+    try {
+        throw "WAT"
+    }
+    catch (e) {
+
+    }
+    finally {
+        return x;
+    }
+}

Original file line number	Diff line number	Diff line change
`@@ -964,7 +964,11 @@ namespace ts {`
`964`	`964`	`currentFlow = preTryFlow;`
`965`	`965`	`bind(node.finallyBlock);`
`966`	`966`	`}`
`967`		`- currentFlow = finishFlowLabel(postFinallyLabel);`
	`967`	`+ // if try statement has finally block and flow after finally block is unreachable - keep it`
	`968`	`+ // otherwise use whatever flow was accumulated at postFinallyLabel`
	`969`	`+ if (!node.finallyBlock \|\| !(currentFlow.flags & FlowFlags.Unreachable)) {`
	`970`	`+ currentFlow = finishFlowLabel(postFinallyLabel);`
	`971`	`+ }`
`968`	`972`	`}`
`969`	`973`
`970`	`974`	`function bindSwitchStatement(node: SwitchStatement): void {`