Update tests and add more tests in a module

Author: ahejlsberg

tests/cases/compiler/narrowingPastLastAssignment.ts

@@ -65,6 +65,27 @@ function f5(x: string | number, cond: () => boolean) {
     action(() => { x /* number */ });
 }
 
+function f5a(cond: boolean) {
+    if (cond) {
+        let x: number | undefined;
+        x = 1;
+        action(() => { x /* number */ });
+    }
+    else {
+        let x: number | undefined;
+        x = 2;
+        action(() => { x /* number */ });
+    }
+}
+
+function f5b() {
+    for (let x = 0; x < 10; x++) {
+        if (x === 1 || x === 2) {
+            action(() => { x /* 1 | 2 */ })
+        }
+    }
+}
+
 // Implicit any variables have a known type following last assignment
 
 function f6() {
@@ -87,6 +108,23 @@ function f7() {
     }
 }
 
+// Narrowings are not preserved for global variables
+
+let g: string | number;
+g = "abc";
+action(() => { g /* string | number */ });
+
+// Narrowings are not preserved for exported namespace members
+
+namespace Foo {
+    export let x: string | number;
+    x = "abc";
+    action(() => { x /* string | number */ });
+    let y: string | number;
+    y = "abc";
+    action(() => { y /* string */ });
+}
+
 // Repros from #35124
 
 function f10() {
@@ -108,10 +146,12 @@ function f11() {
 
 // Repro from #52104
 
-const fooMap: Map<string,Array<number>> = new Map()
-const values = [1, 2, 3, 4, 5];
-let foo = fooMap.get("a");
-if (foo == null) {
-    foo = [];
+function f12() {
+    const fooMap: Map<string,Array<number>> = new Map()
+    const values = [1, 2, 3, 4, 5];
+    let foo = fooMap.get("a");
+    if (foo == null) {
+        foo = [];
+    }
+    values.forEach(v => foo.push(v));
 }
-values.forEach(v => foo.push(v));

tests/cases/compiler/narrowingPastLastAssignmentInModule.ts

@@ -0,0 +1,30 @@
+// @strict: true
+// @noEmit: true
+// @target: esnext
+
+function action(f: Function) {}
+
+// Narrowings are not preserved for exported mutable variables
+
+export let x1: string | number;
+x1 = "abc";
+action(() => { x1 /* string | number */ });
+
+export { x2 };
+let x2: string | number;
+x2 = "abc";
+action(() => { x2 /* string | number */ });
+
+export { x3 as foo };
+let x3: string | number;
+x3 = "abc";
+action(() => { x3 /* string | number */ });
+
+let x4: string | number;
+x4 = "abc";
+action(() => { x4 /* string */ });
+export default x4;
+
+let x5: string | number;
+x5 = "abc";
+action(() => { x5 /* string */ });