Comment in and fix reportNonDefaultExport

internal/checker/checker.go

@@ -13576,7 +13576,27 @@ func (c *Checker) getTargetOfModuleDefault(moduleSymbol *ast.Symbol, node *ast.N
 }
 
 func (c *Checker) reportNonDefaultExport(moduleSymbol *ast.Symbol, node *ast.Node) {
-	// !!!
+	if moduleSymbol.Exports != nil && moduleSymbol.Exports[ast.InternalSymbolNameExportEquals] != nil {
+		c.error(node, diagnostics.Module_0_has_no_default_export_Did_you_mean_to_use_import_1_from_0_instead, c.symbolToString(moduleSymbol), c.symbolToString(node.Symbol()))
+	} else {
+		diagnostic := c.error(node.Name(), diagnostics.Module_0_has_no_default_export, c.symbolToString(moduleSymbol))
+		var exportStar *ast.Symbol
+		if moduleSymbol.Exports != nil {
+			exportStar = moduleSymbol.Exports[ast.InternalSymbolNameExportStar]
+		}
+		if exportStar != nil {
+			defaultExport := core.Find(exportStar.Declarations, func(decl *ast.Declaration) bool {
+				if !(ast.IsExportDeclaration(decl) && decl.AsExportDeclaration().ModuleSpecifier != nil) {
+					return false
+				}
+				resolvedExternalModuleName := c.resolveExternalModuleName(decl, decl.AsExportDeclaration().ModuleSpecifier, false /*ignoreErrors*/)
+				return resolvedExternalModuleName != nil && resolvedExternalModuleName.Exports[ast.InternalSymbolNameDefault] != nil
+			})
+			if defaultExport != nil {
+				diagnostic.AddRelatedInfo(createDiagnosticForNode(defaultExport, diagnostics.X_export_Asterisk_does_not_re_export_a_default))
+			}
+		}
+	}
 }
 
 func (c *Checker) resolveExportByName(moduleSymbol *ast.Symbol, name string, sourceNode *ast.Node, dontResolveAlias bool) *ast.Symbol {
@@ -13773,31 +13793,33 @@ func (c *Checker) isOnlyImportableAsDefault(usage *ast.Node, resolvedModule *ast
 }
 
 func (c *Checker) canHaveSyntheticDefault(file *ast.Node, moduleSymbol *ast.Symbol, dontResolveAlias bool, usage *ast.Node) bool {
-	// !!!
-	// var usageMode ResolutionMode
-	// if file != nil {
-	// 	usageMode = c.getEmitSyntaxForModuleSpecifierExpression(usage)
-	// }
-	// if file != nil && usageMode != core.ModuleKindNone {
-	// 	targetMode := host.getImpliedNodeFormatForEmit(file)
-	// 	if usageMode == core.ModuleKindESNext && targetMode == core.ModuleKindCommonJS && core.ModuleKindNode16 <= c.moduleKind && c.moduleKind <= core.ModuleKindNodeNext {
-	// 		// In Node.js, CommonJS modules always have a synthetic default when imported into ESM
-	// 		return true
-	// 	}
-	// 	if usageMode == core.ModuleKindESNext && targetMode == core.ModuleKindESNext {
-	// 		// No matter what the `module` setting is, if we're confident that both files
-	// 		// are ESM, there cannot be a synthetic default.
-	// 		return false
-	// 	}
-	// }
+	var usageMode core.ResolutionMode
+	if file != nil {
+		usageMode = c.getEmitSyntaxForModuleSpecifierExpression(usage)
+	}
+	if file != nil && usageMode != core.ModuleKindNone {
+		sourceFileMetaData := c.program.GetSourceFileMetaData(file.AsSourceFile().Path())
+		var targetMode core.ModuleKind
+		if sourceFileMetaData != nil {
+			targetMode = sourceFileMetaData.ImpliedNodeFormat
+		}
+		if usageMode == core.ModuleKindESNext && targetMode == core.ModuleKindCommonJS && core.ModuleKindNode16 <= c.moduleKind && c.moduleKind <= core.ModuleKindNodeNext {
+			// In Node.js, CommonJS modules always have a synthetic default when imported into ESM
+			return true
+		}
+		if usageMode == core.ModuleKindESNext && targetMode == core.ModuleKindESNext {
+			// No matter what the `module` setting is, if we're confident that both files
+			// are ESM, there cannot be a synthetic default.
+			return false
+		}
+	}
 	if !c.allowSyntheticDefaultImports {
 		return false
 	}
 	// Declaration files (and ambient modules)
 	if file == nil || file.AsSourceFile().IsDeclarationFile {
 		// Definitely cannot have a synthetic default if they have a syntactic default member specified
-		defaultExportSymbol := c.resolveExportByName(moduleSymbol, ast.InternalSymbolNameDefault /*sourceNode*/, nil /*dontResolveAlias*/, true)
-		// Dont resolve alias because we want the immediately exported symbol's declaration
+		defaultExportSymbol := c.resolveExportByName(moduleSymbol, ast.InternalSymbolNameDefault /*sourceNode*/, nil /*dontResolveAlias*/, true) // Dont resolve alias because we want the immediately exported symbol's declaration
 		if defaultExportSymbol != nil && core.Some(defaultExportSymbol.Declarations, isSyntacticDefault) {
 			return false
 		}
@@ -13814,7 +13836,12 @@ func (c *Checker) canHaveSyntheticDefault(file *ast.Node, moduleSymbol *ast.Symb
 		return true
 	}
 	// TypeScript files never have a synthetic default (as they are always emitted with an __esModule marker) _unless_ they contain an export= statement
-	return hasExportAssignmentSymbol(moduleSymbol)
+	if !ast.IsInJSFile(file) {
+		return hasExportAssignmentSymbol(moduleSymbol)
+	}
+
+	// JS files have a synthetic default if they do not contain ES2015+ module syntax (export = is not valid in js) _and_ do not have an __esModule marker
+	return file.AsSourceFile().ExternalModuleIndicator == nil /* || file.ExternalModuleIndicator == true) */ && c.resolveExportByName(moduleSymbol, "__esModule", nil /*sourceNode*/, dontResolveAlias) == nil // !!!
 }
 
 func (c *Checker) getEmitSyntaxForModuleSpecifierExpression(usage *ast.Node) core.ResolutionMode {

testdata/baselines/reference/submodule/compiler/allowSyntheticDefaultImports3.errors.txt

@@ -0,0 +1,14 @@
+a.ts(1,8): error TS1192: Module '"b"' has no default export.
+
+
+==== a.ts (1 errors) ====
+    import Namespace from "./b";
+           ~~~~~~~~~
+!!! error TS1192: Module '"b"' has no default export.
+    export var x = new Namespace.Foo();
+
+==== b.ts (0 errors) ====
+    export class Foo {
+    	member: string;
+    }
+

testdata/baselines/reference/submodule/compiler/decoratorMetadataWithImportDeclarationNameCollision4.errors.txt.diff

@@ -1,32 +1,17 @@
 --- old.decoratorMetadataWithImportDeclarationNameCollision4.errors.txt
 +++ new.decoratorMetadataWithImportDeclarationNameCollision4.errors.txt
-@@= skipped -0, +-1 lines =@@
+@@= skipped -0, +0 lines =@@
 -service.ts(1,8): error TS2613: Module '"db"' has no default export. Did you mean to use 'import { db } from "db"' instead?
--
--
--==== db.ts (0 errors) ====
--    export class db {
--        public doSomething() {
--        }
--    }
--    
--==== service.ts (1 errors) ====
--    import db from './db'; // error no default export
--           ~~
++service.ts(1,8): error TS1192: Module '"db"' has no default export.
+
+
+ ==== db.ts (0 errors) ====
+@@= skipped -9, +9 lines =@@
+ ==== service.ts (1 errors) ====
+     import db from './db'; // error no default export
+            ~~
 -!!! error TS2613: Module '"db"' has no default export. Did you mean to use 'import { db } from "db"' instead?
--    function someDecorator(target) {
--        return target;
--    }
--    @someDecorator
--    class MyClass {
--        db: db.db;
--    
--        constructor(db: db.db) {
--            this.db = db;
--            this.db.doSomething();
--        }
--    }
--    export {MyClass};
--    
-@@= skipped --1, +1 lines =@@
-+<no content>
++!!! error TS1192: Module '"db"' has no default export.
+     function someDecorator(target) {
+         return target;
+     }

testdata/baselines/reference/submodule/compiler/decoratorMetadataWithImportDeclarationNameCollision4.types

@@ -27,19 +27,19 @@ class MyClass {
 >MyClass : MyClass
 
     db: db.db;
->db : error
+>db : db
 >db : any
 
     constructor(db: db.db) {
->db : error
+>db : db
 >db : any
 
         this.db = db;
->this.db = db : error
->this.db : error
+>this.db = db : db
+>this.db : db
 >this : this
 >db : db
->db : error
+>db : db
 
         this.db.doSomething();
 >this.db.doSomething() : any

testdata/baselines/reference/submodule/compiler/decoratorMetadataWithImportDeclarationNameCollision4.types.diff

@@ -5,24 +5,24 @@
 
      db: db.db;
 ->db : db.db
-+>db : error
++>db : db
  >db : any
 
      constructor(db: db.db) {
 ->db : db.db
-+>db : error
++>db : db
  >db : any
 
          this.db = db;
 ->this.db = db : db.db
 ->this.db : db.db
-+>this.db = db : error
-+>this.db : error
++>this.db = db : db
++>this.db : db
  >this : this
 ->db : db.db
 ->db : db.db
 +>db : db
-+>db : error
++>db : db
 
          this.db.doSomething();
  >this.db.doSomething() : any

testdata/baselines/reference/submodule/compiler/es6ImportDefaultBindingFollowedWithNamespaceBindingWithExport.errors.txt

@@ -1,11 +1,14 @@
 client.ts(1,1): error TS1191: An import declaration cannot have modifiers.
+client.ts(1,15): error TS1192: Module '"server"' has no default export.
 
 
 ==== server.ts (0 errors) ====
     export var a = 10;
 
-==== client.ts (1 errors) ====
+==== client.ts (2 errors) ====
     export import defaultBinding, * as nameSpaceBinding  from "./server";
     ~~~~~~
 !!! error TS1191: An import declaration cannot have modifiers.
+                  ~~~~~~~~~~~~~~
+!!! error TS1192: Module '"server"' has no default export.
     export var x: number = nameSpaceBinding.a;