Fix function hoisting with synthetic source file (#807)

ark120202 · Perryvw · commit 850452554209 · 2020-01-19T16:09:54.000+01:00
diff --git a/src/transformation/context/visitors.ts b/src/transformation/context/visitors.ts
@@ -133,6 +133,7 @@ type NodesBySyntaxKind = {
     [ts.SyntaxKind.NullKeyword]: ts.NullLiteral;
     [ts.SyntaxKind.SuperKeyword]: ts.SuperExpression;
     [ts.SyntaxKind.ThisKeyword]: ts.ThisExpression;
+    [ts.SyntaxKind.NotEmittedStatement]: ts.NotEmittedStatement;
 };
 
 export type ExpressionLikeNode = ts.Expression | ts.QualifiedName | ts.ExternalModuleReference;
diff --git a/src/transformation/utils/typescript/index.ts b/src/transformation/utils/typescript/index.ts
@@ -25,24 +25,12 @@ export function findFirstNodeAbove<T extends ts.Node>(node: ts.Node, callback: (
 }
 
 export function getFirstDeclarationInFile(symbol: ts.Symbol, sourceFile: ts.SourceFile): ts.Declaration | undefined {
-    const declarations = (symbol.getDeclarations() ?? []).filter(
-        // TODO: getSourceFile?
-        declaration => findFirstNodeAbove(declaration, ts.isSourceFile) === sourceFile
-    );
+    const originalSourceFile = ts.getParseTreeNode(sourceFile) ?? sourceFile;
+    const declarations = (symbol.getDeclarations() ?? []).filter(d => d.getSourceFile() === originalSourceFile);
 
     return declarations.length > 0 ? declarations.reduce((p, c) => (p.pos < c.pos ? p : c)) : undefined;
 }
 
-export function isFirstDeclaration(context: TransformationContext, node: ts.VariableDeclaration): boolean {
-    const symbol = context.checker.getSymbolAtLocation(node.name);
-    if (!symbol) {
-        return false;
-    }
-
-    const firstDeclaration = getFirstDeclarationInFile(symbol, context.sourceFile);
-    return firstDeclaration === node;
-}
-
 function isStandardLibraryDeclaration(context: TransformationContext, declaration: ts.Declaration): boolean {
     const sourceFile = declaration.getSourceFile();
     if (!sourceFile) {
diff --git a/src/transformation/visitors/typescript.ts b/src/transformation/visitors/typescript.ts
@@ -22,4 +22,5 @@ export const typescriptVisitors: Visitors = {
     [ts.SyntaxKind.NonNullExpression]: (node, context) => context.transformExpression(node.expression),
     [ts.SyntaxKind.AsExpression]: transformAssertionExpression,
     [ts.SyntaxKind.TypeAssertionExpression]: transformAssertionExpression,
+    [ts.SyntaxKind.NotEmittedStatement]: () => undefined,
 };
diff --git a/test/unit/hoisting.spec.ts b/test/unit/hoisting.spec.ts
@@ -109,6 +109,28 @@ test("Hoisting due to reference from hoisted function", () => {
     expect(result).toBe("foo");
 });
 
+test("Hoisting with synthetic source file node", () => {
+    util.testModule`
+        export const foo = bar();
+        function bar() { return "bar"; }
+    `
+        .setCustomTransformers({
+            before: [
+                () => sourceFile =>
+                    ts.updateSourceFileNode(
+                        sourceFile,
+                        [ts.createNotEmittedStatement(undefined!), ...sourceFile.statements],
+                        sourceFile.isDeclarationFile,
+                        sourceFile.referencedFiles,
+                        sourceFile.typeReferenceDirectives,
+                        sourceFile.hasNoDefaultLib,
+                        sourceFile.libReferenceDirectives
+                    ),
+            ],
+        })
+        .expectToMatchJsResult();
+});
+
 test("Namespace Hoisting", () => {
     const code = `
         function bar() {
diff --git a/test/util.ts b/test/util.ts
@@ -212,6 +212,13 @@ export abstract class TestBuilder {
         return this;
     }
 
+    private customTransformers?: ts.CustomTransformers;
+    public setCustomTransformers(customTransformers?: ts.CustomTransformers): this {
+        expect(this.hasProgram).toBe(false);
+        this.customTransformers = customTransformers;
+        return this;
+    }
+
     // Transpilation and execution
 
     public getTsCode(): string {
@@ -228,7 +235,7 @@ export abstract class TestBuilder {
     @memoize
     public getLuaResult(): tstl.TranspileResult {
         const program = this.getProgram();
-        const result = tstl.transpile({ program });
+        const result = tstl.transpile({ program, customTransformers: this.customTransformers });
         const diagnostics = ts.sortAndDeduplicateDiagnostics([
             ...ts.getPreEmitDiagnostics(program),
             ...result.diagnostics,
