track aliases

src/Bundle.js

@@ -51,6 +51,7 @@ export default class Bundle {
 				this.entryModule = entryModule;
 
 				this.modules.forEach( module => module.bindImportSpecifiers() );
+				this.modules.forEach( module => module.bindAliases() );
 				this.modules.forEach( module => module.bindReferences() );
 
 				// mark all export statements

src/ExternalModule.js

@@ -8,6 +8,10 @@ class ExternalDeclaration {
 		this.isExternal = true;
 	}
 
+	addAlias () {
+		// noop
+	}
+
 	addReference ( reference ) {
 		reference.declaration = this;
 

src/Module.js

@@ -16,6 +16,11 @@ class SyntheticDefaultDeclaration {
 
 		this.original = null;
 		this.isExported = false;
+		this.aliases = [];
+	}
+
+	addAlias ( declaration ) {
+		this.aliases.push( declaration );
 	}
 
 	addReference ( reference ) {
@@ -36,6 +41,8 @@ class SyntheticDefaultDeclaration {
 	use () {
 		this.isUsed = true;
 		this.statement.mark();
+
+		this.aliases.forEach( alias => alias.use() );
 	}
 }
 
@@ -45,6 +52,7 @@ class SyntheticNamespaceDeclaration {
 		this.name = null;
 
 		this.needsNamespaceBlock = false;
+		this.aliases = [];
 
 		this.originals = blank();
 		module.getExports().forEach( name => {
@@ -52,6 +60,10 @@ class SyntheticNamespaceDeclaration {
 		});
 	}
 
+	addAlias ( declaration ) {
+		this.aliases.push( declaration );
+	}
+
 	addReference ( reference ) {
 		// if we have e.g. `foo.bar`, we can optimise
 		// the reference by pointing directly to `bar`
@@ -102,7 +114,8 @@ class SyntheticNamespaceDeclaration {
 	}
 
 	use () {
-		// noop
+		// noop?
+		this.aliases.forEach( alias => alias.use() );
 	}
 }
 
@@ -287,6 +300,21 @@ export default class Module {
 		return makeLegalIdentifier( basename( this.id ).slice( 0, -extname( this.id ).length ) );
 	}
 
+	bindAliases () {
+		keys( this.declarations ).forEach( name => {
+			const declaration = this.declarations[ name ];
+			const statement = declaration.statement;
+			if ( statement.node.type !== 'VariableDeclaration' ) return;
+
+			statement.references.forEach( reference => {
+				if ( reference.name === name || !reference.isImmediatelyUsed ) return;
+
+				const otherDeclaration = this.trace( reference.name );
+				if ( otherDeclaration ) otherDeclaration.addAlias( declaration );
+			});
+		});
+	}
+
 	bindImportSpecifiers () {
 		[ this.imports, this.reexports ].forEach( specifiers => {
 			keys( specifiers ).forEach( name => {

src/ast/Scope.js

@@ -39,6 +39,11 @@ class Declaration {
 		this.name = null;
 
 		this.isReassigned = false;
+		this.aliases = [];
+	}
+
+	addAlias ( declaration ) {
+		this.aliases.push( declaration );
 	}
 
 	addReference ( reference ) {
@@ -58,6 +63,8 @@ class Declaration {
 	use () {
 		this.isUsed = true;
 		if ( this.statement ) this.statement.mark();
+
+		this.aliases.forEach( alias => alias.use() );
 	}
 }
 

test/function/tracks-alias-mutations/_config.js

@@ -1,4 +1,3 @@
 module.exports = {
-	description: 'tracks mutations of aliased objects',
-	skip: true
+	description: 'tracks mutations of aliased objects'
 };