Remove isElisionBlocked (#2673)

Author: jakebailey

internal/transformers/tstransforms/importelision.go

@@ -27,30 +27,26 @@ func NewImportElisionTransformer(opt *transformers.TransformOptions) *transforme
 func (tx *ImportElisionTransformer) visit(node *ast.Node) *ast.Node {
 	switch node.Kind {
 	case ast.KindImportEqualsDeclaration:
-		if !tx.isElisionBlocked(node) {
-			if ast.IsExternalModuleImportEqualsDeclaration(node) {
-				if !tx.shouldEmitAliasDeclaration(node) {
-					return nil
-				}
-			} else {
-				if !tx.shouldEmitImportEqualsDeclaration(node.AsImportEqualsDeclaration()) {
-					return nil
-				}
+		if ast.IsExternalModuleImportEqualsDeclaration(node) {
+			if !tx.shouldEmitAliasDeclaration(node) {
+				return nil
+			}
+		} else {
+			if !tx.shouldEmitImportEqualsDeclaration(node.AsImportEqualsDeclaration()) {
+				return nil
 			}
 		}
 		return tx.Visitor().VisitEachChild(node)
 	case ast.KindImportDeclaration:
-		if !tx.isElisionBlocked(node) {
-			n := node.AsImportDeclaration()
-			// Do not elide a side-effect only import declaration.
-			//  import "foo";
-			if n.ImportClause != nil {
-				importClause := tx.Visitor().VisitNode(n.ImportClause)
-				if importClause == nil {
-					return nil
-				}
-				return tx.Factory().UpdateImportDeclaration(n, n.Modifiers(), importClause, n.ModuleSpecifier, tx.Visitor().VisitNode(n.Attributes))
+		n := node.AsImportDeclaration()
+		// Do not elide a side-effect only import declaration.
+		//  import "foo";
+		if n.ImportClause != nil {
+			importClause := tx.Visitor().VisitNode(n.ImportClause)
+			if importClause == nil {
+				return nil
 			}
+			return tx.Factory().UpdateImportDeclaration(n, n.Modifiers(), importClause, n.ModuleSpecifier, tx.Visitor().VisitNode(n.Attributes))
 		}
 		return tx.Visitor().VisitEachChild(node)
 	case ast.KindImportClause:
@@ -83,25 +79,22 @@ func (tx *ImportElisionTransformer) visit(node *ast.Node) *ast.Node {
 		}
 		return node
 	case ast.KindExportAssignment:
-		if !tx.isElisionBlocked(node) && !tx.compilerOptions.VerbatimModuleSyntax.IsTrue() && !tx.isValueAliasDeclaration(node) {
+		if !tx.compilerOptions.VerbatimModuleSyntax.IsTrue() && !tx.isValueAliasDeclaration(node) {
 			// elide unused import
 			return nil
 		}
 		return tx.Visitor().VisitEachChild(node)
 	case ast.KindExportDeclaration:
-		if !tx.isElisionBlocked(node) {
-			n := node.AsExportDeclaration()
-			var exportClause *ast.Node
-			if n.ExportClause != nil {
-				exportClause = tx.Visitor().VisitNode(n.ExportClause)
-				if exportClause == nil {
-					// all export bindings were elided
-					return nil
-				}
+		n := node.AsExportDeclaration()
+		var exportClause *ast.Node
+		if n.ExportClause != nil {
+			exportClause = tx.Visitor().VisitNode(n.ExportClause)
+			if exportClause == nil {
+				// all export bindings were elided
+				return nil
 			}
-			return tx.Factory().UpdateExportDeclaration(n, nil /*modifiers*/, false /*isTypeOnly*/, exportClause, tx.Visitor().VisitNode(n.ModuleSpecifier), tx.Visitor().VisitNode(n.Attributes))
 		}
-		return tx.Visitor().VisitEachChild(node)
+		return tx.Factory().UpdateExportDeclaration(n, nil /*modifiers*/, false /*isTypeOnly*/, exportClause, tx.Visitor().VisitNode(n.ModuleSpecifier), tx.Visitor().VisitNode(n.Attributes))
 	case ast.KindNamedExports:
 		n := node.AsNamedExports()
 		elements := tx.Visitor().VisitNodes(n.Elements)
@@ -152,56 +145,3 @@ func (tx *ImportElisionTransformer) isTopLevelValueImportEqualsWithEntityName(no
 	node = tx.EmitContext().ParseNode(node)
 	return node != nil && tx.emitResolver.IsTopLevelValueImportEqualsWithEntityName(node)
 }
-
-// Determines whether import/export elision is blocked for this statement.
-//
-// @description
-// We generally block import/export elision if the statement was modified by a `before` custom
-// transform, although we will continue to allow it if the statement hasn't replaced a node of a different kind and
-// as long as the local bindings for the declarations are unchanged.
-func (tx *ImportElisionTransformer) isElisionBlocked(node *ast.Node /*ImportDeclaration | ImportEqualsDeclaration | ExportAssignment | ExportDeclaration*/) bool {
-	parsed := tx.EmitContext().ParseNode(node)
-	if parsed == node || ast.IsExportAssignment(node) {
-		return false
-	}
-
-	if parsed == nil || parsed.Kind != node.Kind {
-		// no longer safe to elide as the declaration was replaced with a node of a different kind
-		return true
-	}
-
-	switch node.Kind {
-	case ast.KindImportDeclaration:
-		n := node.AsImportDeclaration()
-		p := parsed.AsImportDeclaration()
-		if n.ImportClause != p.ImportClause {
-			return true // no longer safe to elide as the import clause has changed
-		}
-		if n.Attributes != p.Attributes {
-			return true // no longer safe to elide as the import attributes have changed
-		}
-	case ast.KindImportEqualsDeclaration:
-		n := node.AsImportEqualsDeclaration()
-		p := parsed.AsImportEqualsDeclaration()
-		if n.Name() != p.Name() {
-			return true // no longer safe to elide as local binding has changed
-		}
-		if n.IsTypeOnly != p.IsTypeOnly {
-			return true // no longer safe to elide as `type` modifier has changed
-		}
-		if n.ModuleReference != p.ModuleReference && (ast.IsEntityName(n.ModuleReference) || ast.IsEntityName(p.ModuleReference)) {
-			return true // no longer safe to elide as EntityName reference has changed.
-		}
-	case ast.KindExportDeclaration:
-		n := node.AsExportDeclaration()
-		p := parsed.AsExportDeclaration()
-		if n.ExportClause != p.ExportClause {
-			return true // no longer safe to elide as the export clause has changed
-		}
-		if n.Attributes != p.Attributes {
-			return true // no longer safe to elide as the export attributes have changed
-		}
-	}
-
-	return false
-}

testdata/baselines/reference/submodule/conformance/importSpecifiers1.js

@@ -62,7 +62,7 @@ type; // Error (cannot resolve name)
 as; // Error (used in emitting position)
 export {};
 //// [d.js]
-import "./mod.js"; // Error
+export {};
 //// [e.js]
 import { type as type } from "./mod.js";
 type;

testdata/baselines/reference/submodule/conformance/importSpecifiers1.js.diff

@@ -30,8 +30,6 @@ export interface LocalInterface extends RequireInterface, ImportInterface {}
 //// [index.js]
 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
-// not exclusively type-only
-require("pkg");
 
 
 //// [index.d.ts]

testdata/baselines/reference/submodule/conformance/nodeModulesImportAttributesModeDeclarationEmitErrors(module=node16).js

@@ -30,8 +30,6 @@ export interface LocalInterface extends RequireInterface, ImportInterface {}
 //// [index.js]
 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
-// not exclusively type-only
-require("pkg");
 
 
 //// [index.d.ts]

testdata/baselines/reference/submodule/conformance/nodeModulesImportAttributesModeDeclarationEmitErrors(module=node16).js.diff

@@ -30,8 +30,6 @@ export interface LocalInterface extends RequireInterface, ImportInterface {}
 //// [index.js]
 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
-// not exclusively type-only
-require("pkg");
 
 
 //// [index.d.ts]

testdata/baselines/reference/submodule/conformance/nodeModulesImportAttributesModeDeclarationEmitErrors(module=node18).js

@@ -30,8 +30,6 @@ export interface LocalInterface extends RequireInterface, ImportInterface {}
 //// [index.js]
 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
-// not exclusively type-only
-require("pkg");
 
 
 //// [index.d.ts]