Fix crash on bad namespace parse (#37626)

* Fix crash on bad namespace parse

`global` inside a class body is parsed as a module declaration, and in
the following example has no body:

```ts
class C {
  global x
}
```

`x` is parsed as a separate ExpressionStatement. This caused a crash in
emit because the code didn't expect a module declaration with no body.

* inline node.body variable

* fix missed references to body

src/compiler/transformers/ts.ts

@@ -2693,27 +2693,28 @@ namespace ts {
             const statements: Statement[] = [];
             startLexicalEnvironment();
 
-            let statementsLocation: TextRange;
+            let statementsLocation: TextRange | undefined;
             let blockLocation: TextRange | undefined;
-            const body = node.body!;
-            if (body.kind === SyntaxKind.ModuleBlock) {
-                saveStateAndInvoke(body, body => addRange(statements, visitNodes((<ModuleBlock>body).statements, namespaceElementVisitor, isStatement)));
-                statementsLocation = body.statements;
-                blockLocation = body;
-            }
-            else {
-                const result = visitModuleDeclaration(<ModuleDeclaration>body);
-                if (result) {
-                    if (isArray(result)) {
-                        addRange(statements, result);
-                    }
-                    else {
-                        statements.push(result);
-                    }
+            if (node.body) {
+                if (node.body.kind === SyntaxKind.ModuleBlock) {
+                    saveStateAndInvoke(node.body, body => addRange(statements, visitNodes((<ModuleBlock>body).statements, namespaceElementVisitor, isStatement)));
+                    statementsLocation = node.body.statements;
+                    blockLocation = node.body;
                 }
+                else {
+                    const result = visitModuleDeclaration(<ModuleDeclaration>node.body);
+                    if (result) {
+                        if (isArray(result)) {
+                            addRange(statements, result);
+                        }
+                        else {
+                            statements.push(result);
+                        }
+                    }
 
-                const moduleBlock = <ModuleBlock>getInnerMostModuleDeclarationFromDottedModule(node)!.body;
-                statementsLocation = moveRangePos(moduleBlock.statements, -1);
+                    const moduleBlock = <ModuleBlock>getInnerMostModuleDeclarationFromDottedModule(node)!.body;
+                    statementsLocation = moveRangePos(moduleBlock.statements, -1);
+                }
             }
 
             insertStatementsAfterStandardPrologue(statements, endLexicalEnvironment());
@@ -2750,7 +2751,7 @@ namespace ts {
             //     })(hi = hello.hi || (hello.hi = {}));
             // })(hello || (hello = {}));
             // We only want to emit comment on the namespace which contains block body itself, not the containing namespaces.
-            if (body.kind !== SyntaxKind.ModuleBlock) {
+            if (!node.body || node.body.kind !== SyntaxKind.ModuleBlock) {
                 setEmitFlags(block, getEmitFlags(block) | EmitFlags.NoComments);
             }
             return block;

tests/baselines/reference/nestedGlobalNamespaceInClass.errors.txt

@@ -0,0 +1,26 @@
+tests/cases/compiler/nestedGlobalNamespaceInClass.ts(3,5): error TS1068: Unexpected token. A constructor, method, accessor, or property was expected.
+tests/cases/compiler/nestedGlobalNamespaceInClass.ts(3,5): error TS2669: Augmentations for the global scope can only be directly nested in external modules or ambient module declarations.
+tests/cases/compiler/nestedGlobalNamespaceInClass.ts(3,5): error TS2670: Augmentations for the global scope should have 'declare' modifier unless they appear in already ambient context.
+tests/cases/compiler/nestedGlobalNamespaceInClass.ts(3,12): error TS1005: ';' expected.
+tests/cases/compiler/nestedGlobalNamespaceInClass.ts(3,12): error TS2304: Cannot find name 'x'.
+tests/cases/compiler/nestedGlobalNamespaceInClass.ts(4,1): error TS1128: Declaration or statement expected.
+
+
+==== tests/cases/compiler/nestedGlobalNamespaceInClass.ts (6 errors) ====
+    // should not crash - from #35717
+    class C {
+        global x
+        ~~~~~~
+!!! error TS1068: Unexpected token. A constructor, method, accessor, or property was expected.
+        ~~~~~~
+!!! error TS2669: Augmentations for the global scope can only be directly nested in external modules or ambient module declarations.
+        ~~~~~~
+!!! error TS2670: Augmentations for the global scope should have 'declare' modifier unless they appear in already ambient context.
+               ~
+!!! error TS1005: ';' expected.
+               ~
+!!! error TS2304: Cannot find name 'x'.
+    }
+    ~
+!!! error TS1128: Declaration or statement expected.
+    

tests/baselines/reference/nestedGlobalNamespaceInClass.js

@@ -0,0 +1,18 @@
+//// [nestedGlobalNamespaceInClass.ts]
+// should not crash - from #35717
+class C {
+    global x
+}
+
+
+//// [nestedGlobalNamespaceInClass.js]
+// should not crash - from #35717
+var C = /** @class */ (function () {
+    function C() {
+    }
+    return C;
+}());
+var global;
+(function (global) {
+})(global || (global = {}));
+x;

tests/baselines/reference/nestedGlobalNamespaceInClass.symbols

@@ -0,0 +1,9 @@
+=== tests/cases/compiler/nestedGlobalNamespaceInClass.ts ===
+// should not crash - from #35717
+class C {
+>C : Symbol(C, Decl(nestedGlobalNamespaceInClass.ts, 0, 0))
+
+    global x
+>global : Symbol(global, Decl(nestedGlobalNamespaceInClass.ts, 1, 9))
+}
+

tests/baselines/reference/nestedGlobalNamespaceInClass.types

@@ -0,0 +1,10 @@
+=== tests/cases/compiler/nestedGlobalNamespaceInClass.ts ===
+// should not crash - from #35717
+class C {
+>C : C
+
+    global x
+>global : any
+>x : any
+}
+

tests/cases/compiler/nestedGlobalNamespaceInClass.ts

@@ -0,0 +1,4 @@
+// should not crash - from #35717
+class C {
+    global x
+}