JS Interop Facade generation polish.

lib/merge.ts

Index: lib/merge.ts
diff --git a/lib/merge.ts b/lib/merge.ts
index 0b9c8d746496b1608dd7eb08d7b35a25735520ed..49180029a4467d5b680f36e0e183f9e4a1567df0 100644
--- a/lib/merge.ts
+++ b/lib/merge.ts
@@ -14,12 +14,18 @@ export class MergedType {
     if (t) {
       // TODO(jacobr): get a better unique name for a type.
       switch (t.kind) {
+        case ts.SyntaxKind.NullKeyword:
+          // No need to include the null type as all Dart types are nullable anyway.
+          return;
         case ts.SyntaxKind.UnionType:
           let union = <ts.UnionTypeNode>t;
           union.types.forEach(this.merge.bind(this));
           return;
-        case ts.SyntaxKind.LastTypeNode:
-          this.merge((t as ts.ParenthesizedTypeNode).type);
+        case ts.SyntaxKind.IntersectionType:
+          // Arbitrarily pick the first type of the intersection type as the merged type.
+          // TODO(jacobr): re-evaluate this logic.
+          let intersection = <ts.IntersectionTypeNode>t;
+          this.merge(intersection.types[0]);
           return;
         case ts.SyntaxKind.TypePredicate:
           this.merge((t as ts.TypePredicateNode).type);
@@ -31,19 +37,21 @@ export class MergedType {
           let decl = this.fc.getDeclaration(typeRef.typeName);
           if (decl !== null && decl.kind === ts.SyntaxKind.TypeAliasDeclaration) {
             let alias = <ts.TypeAliasDeclaration>decl;
+            if (!base.supportedAliasType(alias)) {
+              if (typeRef.typeArguments) {
+                console.log(
+                    'Warning: typeReference with arguements not supported yet:' + t.getText());
+              }
 
-            if (typeRef.typeArguments) {
-              throw 'TypeReference with arguements not supported yet:' + t.getText();
+              this.merge(alias.type);
             }
-
-            this.merge(alias.type);
             return;
           }
           break;
         default:
           break;
       }
-      this.types[this.fc.generateDartTypeName(t, true)] = t;
+      this.types[this.fc.generateDartTypeName(t, {insideComment: true})] = t;
     }
   }
 
@@ -109,9 +117,91 @@ export class MergedParameter {
 }
 
 /**
+ * Handle a parameter that is the result of merging parameter declarations from
+ * multiple method overloads.
+ */
+export class MergedTypeParameter {
+  constructor(param: ts.TypeParameterDeclaration, fc: FacadeConverter) {
+    this.constraint = new MergedType(fc);
+    this.textRange = param;
+    this.merge(param);
+    this.name = base.ident(param.name);
+  }
+
+  merge(param: ts.TypeParameterDeclaration) {
+    this.constraint.merge(param.constraint);
+    // We ignore param.expression as it is not supported by Dart.
+  }
+
+  toTypeParameterDeclaration(): ts.TypeParameterDeclaration {
+    let ret = <ts.TypeParameterDeclaration>ts.createNode(ts.SyntaxKind.TypeParameter);
+    let nameIdentifier = <ts.Identifier>ts.createNode(ts.SyntaxKind.Identifier);
+    nameIdentifier.text = this.name;
+    ret.name = nameIdentifier;
+    base.copyLocation(this.textRange, ret);
+    let constraint = this.constraint.toTypeNode();
+    // TODO(jacobr): remove this check once we have support for union types within comments.
+    // We can't currently handle union types in merged type parameters as the comments for type
+    // parameters in function types are not there for documentation and impact strong mode.
+    if (constraint && constraint.kind !== ts.SyntaxKind.UnionType) {
+      ret.constraint = constraint;
+    }
+    return ret;
+  }
+
+  private name: string;
+  private constraint: MergedType;
+  private textRange: ts.TextRange;
+}
+
+/**
+ * Handle a parameter that is the result of merging parameter declarations from
+ * multiple method overloads.
+ */
+export class MergedTypeParameters {
+  private mergedParameters: {[s: string]: MergedTypeParameter} = {};
+  private textRange: ts.TextRange;
+
+  constructor(private fc: FacadeConverter) {}
+
+  merge(params: ts.NodeArray<ts.TypeParameterDeclaration>) {
+    if (!params) return;
+    if (!this.textRange) {
+      this.textRange = params;
+    }
+    for (let i = 0; i < params.length; i++) {
+      let param = params[i];
+      let name = base.ident(param.name);
+      if (Object.hasOwnProperty.call(this.mergedParameters, name)) {
+        let merged = this.mergedParameters[name];
+        if (merged) {
+          merged.merge(param);
+        }
+      } else {
+        this.mergedParameters[name] = new MergedTypeParameter(param, this.fc);
+      }
+    }
+  }
+
+  toTypeParameters(): ts.NodeArray<ts.TypeParameterDeclaration> {
+    let names = Object.getOwnPropertyNames(this.mergedParameters);
+    if (names.length === 0) {
+      return undefined;
+    }
+
+    let ret = [] as ts.NodeArray<ts.TypeParameterDeclaration>;
+    base.copyLocation(this.textRange, ret);
+    for (let i = 0; i < names.length; ++i) {
+      ret.push(this.mergedParameters[names[i]].toTypeParameterDeclaration());
+    }
+    return ret;
+  }
+}
+
+/**
  * Normalize a SourceFile
  */
-export function normalizeSourceFile(f: ts.SourceFile) {
+export function normalizeSourceFile(f: ts.SourceFile, fc: FacadeConverter) {
   let modules: {[name: string]: ts.ModuleDeclaration} = {};
 
   // Merge top level modules.
@@ -120,7 +210,7 @@ export function normalizeSourceFile(f: ts.SourceFile) {
     if (statement.kind !== ts.SyntaxKind.ModuleDeclaration) continue;
     let moduleDecl = <ts.ModuleDeclaration>statement;
     let name = moduleDecl.name.text;
-    if (modules.hasOwnProperty(name)) {
+    if (Object.hasOwnProperty.call(modules, name)) {
       let srcBody = modules[name].body;
       let srcBodyBlock: ts.ModuleBlock;
 
@@ -162,13 +252,78 @@ export function normalizeSourceFile(f: ts.SourceFile) {
             declaration: ts.VariableDeclaration) {
           if (declaration.name.kind === ts.SyntaxKind.Identifier) {
             let name: string = (<ts.Identifier>(declaration.name)).text;
-            if (classes.hasOwnProperty(name)) {
+            let existingClass = Object.hasOwnProperty.call(classes, name);
+            let hasConstructor = false;
+            if (declaration.type) {
+              let type: ts.TypeNode = declaration.type;
+              if (type.kind === ts.SyntaxKind.TypeLiteral) {
+                let literal = <ts.TypeLiteralNode>type;
+                hasConstructor = literal.members.some((member: ts.Node) => {
+                  return member.kind === ts.SyntaxKind.ConstructSignature;
+                });
+              } else if (type.kind === ts.SyntaxKind.TypeReference) {
+                // Handle interfaces with constructors. As Dart does not support calling arbitrary
+                // functions like constructors we need to upgrade the interface to be a class
+                // so we call invoke the constructor on the interface class.
+                // Example typescript library definition matching this pattern:
+                //
+                // interface XStatic {
+                //   new (a: string, b): XStatic;
+                //   foo();
+                // }
+                //
+                // declare var X: XStatic;
+                //
+                // In JavaScript you could just write new X() and create an
+                // instance of XStatic. We don't
+                let typeRef = type as ts.TypeReferenceNode;
+                let typeName = typeRef.typeName;
+                let symbol = fc.tc.getSymbolAtLocation(typeName);
+                if (symbol == null) return;
+                let decl = fc.getSymbolDeclaration(symbol, typeName);
+                if (decl == null) return;
+                if (decl.kind !== ts.SyntaxKind.InterfaceDeclaration) return;
+                let interfaceDecl = decl as base.ExtendedInterfaceDeclaration;
+                if (!interfaceDecl.members.some(
+                        (member) => { return member.kind === ts.SyntaxKind.ConstructSignature; }))
+                  return;
+
+                if (interfaceDecl.classLikeVariableDeclaration == null) {
+                  // We could add extra logic to be safer such as only infering that variable names
+                  // are class like for cases where variable names are UpperCamelCase matching JS
+                  // conventions that a variable is a Class definition.
+                  interfaceDecl.classLikeVariableDeclaration = declaration;
+                }
+              }
+            }
+
+            if (existingClass || hasConstructor) {
+              if (!existingClass) {
+                // Create a stub existing class to upgrade the object literal to if there is not an
+                // existing class with the same name.
+                let clazz = <ts.ClassDeclaration>ts.createNode(ts.SyntaxKind.ClassDeclaration);
+                base.copyLocation(declaration, clazz);
+                clazz.name = declaration.name as ts.Identifier;
+                clazz.members = <ts.NodeArray<ts.ClassElement>>[];
+                base.copyLocation(declaration, clazz.members);
+                replaceNode(n, clazz);
+                classes[name] = clazz;
+              }
+
               let existing = classes[name];
+              if (existing.kind === ts.SyntaxKind.InterfaceDeclaration) {
+                let interfaceDecl = existing as base.ExtendedInterfaceDeclaration;
+                // It is completely safe to assume that we know the precise class like variable
+                // declaration for the interface in this case as they have the same exact name.
+                interfaceDecl.classLikeVariableDeclaration = declaration;
+              }
               let members = existing.members as Array<ts.ClassElement>;
               if (declaration.type) {
                 let type: ts.TypeNode = declaration.type;
                 if (type.kind === ts.SyntaxKind.TypeLiteral) {
-                  removeNode(n);
+                  if (existingClass) {
+                    removeNode(n);
+                  }
                   let literal = <ts.TypeLiteralNode>type;
                   literal.members.forEach((member: ts.Node) => {
                     switch (member.kind) {
@@ -249,37 +404,29 @@ export function normalizeSourceFile(f: ts.SourceFile) {
     }
   }
 
-  function makeCallableClassesImplementFunction(decl: base.ClassLike) {
-    if (base.isCallable(decl)) {
-      // Modify the AST to explicitly state that the class implements Function
-      if (!decl.heritageClauses) {
-        decl.heritageClauses = <ts.NodeArray<ts.HeritageClause>>[];
-        base.copyLocation(decl, decl.heritageClauses);
-      }
-      let clauses = decl.heritageClauses;
-      let clause = base.arrayFindPolyfill(
-          clauses, (c) => c.token !== ts.SyntaxKind.ExtendsKeyword ||
-              decl.kind === ts.SyntaxKind.InterfaceDeclaration);
-      if (clause == null) {
-        clause = <ts.HeritageClause>ts.createNode(ts.SyntaxKind.HeritageClause);
-        clause.token = decl.kind === ts.SyntaxKind.InterfaceDeclaration ?
-            ts.SyntaxKind.ExtendsKeyword :
-            ts.SyntaxKind.ImplementsKeyword;
-        clause.types = <ts.NodeArray<ts.ExpressionWithTypeArguments>>[];
-        clause.parent = decl;
-        base.copyLocation(decl, clause);
-        clauses.push(clause);
+  function replaceInArray(nodes: ts.NodeArray<ts.Node>, v: ts.Node, replacement: ts.Node) {
+    for (let i = 0, len = nodes.length; i < len; ++i) {
+      if (nodes[i] === v) {
+        nodes[i] = replacement;
+        break;
       }
-      let functionType =
-          <ts.ExpressionWithTypeArguments>ts.createNode(ts.SyntaxKind.ExpressionWithTypeArguments);
-      functionType.parent = clause;
-      base.copyLocation(clause, functionType);
-      let fn = <ts.Identifier>ts.createNode(ts.SyntaxKind.Identifier);
-      fn.text = 'Function';
-      fn.parent = functionType;
-      base.copyLocation(functionType, fn);
-      functionType.expression = fn;
-      clause.types.push(functionType);
+    }
+  }
+
+  function replaceNode(n: ts.Node, replacement: ts.Node) {
+    let parent = n.parent;
+    replacement.parent = parent;
+    switch (parent.kind) {
+      case ts.SyntaxKind.ModuleBlock:
+        let block = <ts.ModuleBlock>parent;
+        replaceInArray(block.statements, n, replacement);
+        break;
+      case ts.SyntaxKind.SourceFile:
+        let sourceFile = <ts.SourceFile>parent;
+        replaceInArray(sourceFile.statements, n, replacement);
+        break;
+      default:
+        throw 'replaceNode not implemented for kind:' + parent.kind;
     }
   }
 
@@ -291,7 +438,7 @@ export function normalizeSourceFile(f: ts.SourceFile) {
         let name = classDecl.name.text;
         // TODO(jacobr): validate that the classes have consistent
         // modifiers, etc.
-        if (classes.hasOwnProperty(name)) {
+        if (Object.hasOwnProperty.call(classes, name)) {
           let existing = classes[name];
           (classDecl.members as Array<ts.ClassElement>).forEach((e: ts.ClassElement) => {
             (existing.members as Array<ts.ClassElement>).push(e);
@@ -301,7 +448,6 @@ export function normalizeSourceFile(f: ts.SourceFile) {
         } else {
           classes[name] = classDecl;
           // Perform other class level post processing here.
-          makeCallableClassesImplementFunction(classDecl);
         }
         break;
       case ts.SyntaxKind.ModuleDeclaration: