Fix enums and namespace merge (#47059)

* Fix enums and namespace merge

* Remove unused comment

src/compiler/checker.ts

@@ -39397,7 +39397,7 @@ namespace ts {
                 if (memberSymbol) {
                     const declaration = memberSymbol.valueDeclaration;
                     if (declaration !== member) {
-                        if (declaration && isBlockScopedNameDeclaredBeforeUse(declaration, member)) {
+                        if (declaration && isBlockScopedNameDeclaredBeforeUse(declaration, member) && isEnumDeclaration(declaration.parent)) {
                             return getEnumMemberValue(declaration as EnumMember);
                         }
                         error(expr, Diagnostics.A_member_initializer_in_a_enum_declaration_cannot_reference_members_declared_after_it_including_members_defined_in_other_enums);

tests/baselines/reference/enumWithExport.errors.txt

@@ -0,0 +1,12 @@
+tests/cases/compiler/enumWithExport.ts(5,7): error TS2651: A member initializer in a enum declaration cannot reference members declared after it, including members defined in other enums.
+
+
+==== tests/cases/compiler/enumWithExport.ts (1 errors) ====
+    namespace x {
+      export let y = 123
+    }
+    enum x {
+      z = y
+          ~
+!!! error TS2651: A member initializer in a enum declaration cannot reference members declared after it, including members defined in other enums.
+    }

tests/baselines/reference/enumWithExport.js

@@ -0,0 +1,16 @@
+//// [enumWithExport.ts]
+namespace x {
+  export let y = 123
+}
+enum x {
+  z = y
+}
+
+//// [enumWithExport.js]
+var x;
+(function (x) {
+    x.y = 123;
+})(x || (x = {}));
+(function (x) {
+    x[x["z"] = 0] = "z";
+})(x || (x = {}));

tests/baselines/reference/enumWithExport.symbols

@@ -0,0 +1,13 @@
+=== tests/cases/compiler/enumWithExport.ts ===
+namespace x {
+>x : Symbol(x, Decl(enumWithExport.ts, 0, 0), Decl(enumWithExport.ts, 2, 1))
+
+  export let y = 123
+>y : Symbol(y, Decl(enumWithExport.ts, 1, 12))
+}
+enum x {
+>x : Symbol(x, Decl(enumWithExport.ts, 0, 0), Decl(enumWithExport.ts, 2, 1))
+
+  z = y
+>z : Symbol(x.z, Decl(enumWithExport.ts, 3, 8))
+}

tests/baselines/reference/enumWithExport.types

@@ -0,0 +1,15 @@
+=== tests/cases/compiler/enumWithExport.ts ===
+namespace x {
+>x : typeof x
+
+  export let y = 123
+>y : number
+>123 : 123
+}
+enum x {
+>x : x
+
+  z = y
+>z : x.z
+>y : any
+}

tests/cases/compiler/enumWithExport.ts

@@ -0,0 +1,6 @@
+namespace x {
+  export let y = 123
+}
+enum x {
+  z = y
+}