Fix merging of JS value & TS type decl

Fixes microsoft#38383

src/compiler/checker.ts

@@ -7870,7 +7870,7 @@ namespace ts {
                 (resolvedSymbol || symbol).exports!.forEach((s, name) => {
                     const exportedMember = members.get(name)!;
                     if (exportedMember && exportedMember !== s) {
-                        if (s.flags & SymbolFlags.Value) {
+                        if (s.flags & SymbolFlags.Value && exportedMember.flags & SymbolFlags.Value) {
                             // If the member has an additional value-like declaration, union the types from the two declarations,
                             // but issue an error if they occurred in two different files. The purpose is to support a JS file with
                             // a pattern like:

tests/baselines/reference/jsExportMemberMergedWithModuleAugmentation3.symbols

@@ -0,0 +1,19 @@
+=== /x.js ===
+module.exports.x = 1;
+>module.exports.x : Symbol(x, Decl(x.js, 0, 0), Decl(y.d.ts, 0, 0))
+>module.exports : Symbol(x, Decl(x.js, 0, 0), Decl(y.d.ts, 0, 0))
+>module : Symbol(module, Decl(x.js, 0, 0))
+>exports : Symbol("/x", Decl(x.js, 0, 0))
+>x : Symbol(x, Decl(x.js, 0, 0), Decl(y.d.ts, 0, 0))
+
+module.exports = require("./y.js");
+>module.exports : Symbol("/x", Decl(x.js, 0, 0))
+>module : Symbol(export=, Decl(x.js, 0, 21))
+>exports : Symbol(export=, Decl(x.js, 0, 21))
+>require : Symbol(require)
+>"./y.js" : Symbol("/y", Decl(y.d.ts, 0, 0))
+
+=== /y.d.ts ===
+export declare type x = 1;
+>x : Symbol(x, Decl(x.js, 0, 0), Decl(y.d.ts, 0, 0))
+

tests/baselines/reference/jsExportMemberMergedWithModuleAugmentation3.types

@@ -0,0 +1,23 @@
+=== /x.js ===
+module.exports.x = 1;
+>module.exports.x = 1 : 1
+>module.exports.x : number
+>module.exports : typeof import("/y")
+>module : { "\"/x\"": typeof import("/y"); }
+>exports : typeof import("/y")
+>x : number
+>1 : 1
+
+module.exports = require("./y.js");
+>module.exports = require("./y.js") : typeof import("/y")
+>module.exports : typeof import("/y")
+>module : { "\"/x\"": typeof import("/y"); }
+>exports : typeof import("/y")
+>require("./y.js") : typeof import("/y")
+>require : any
+>"./y.js" : "./y.js"
+
+=== /y.d.ts ===
+export declare type x = 1;
+>x : 1
+

tests/cases/compiler/jsExportMemberMergedWithModuleAugmentation3.ts

@@ -0,0 +1,10 @@
+// @allowJs: true
+// @checkJs: true
+// @noEmit: true
+
+// @Filename: /x.js
+module.exports.x = 1;
+module.exports = require("./y.js");
+
+// @Filename: /y.d.ts
+export declare type x = 1;