[dartdevc] Generating nested functions that invoke super as arrow fun…

…ctions (e.g., mixins) Issue: dart-lang/sdk#34806 Change-Id: I7f5297dbdfbf928258146f28f85043f735acacb2 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/97686 Reviewed-by: Nicholas Shahan <nshahan@google.com> Reviewed-by: Jenny Messerly <jmesserly@google.com> Commit-Queue: Mark Zhou <markzipan@google.com>
flutter · Mar 26, 2019 · e1a6893 · e1a6893
1 parent 3a37316
commit e1a6893
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Showing 4 changed files with 43 additions and 34 deletions.
diff --git a/pkg/dev_compiler/lib/src/analyzer/code_generator.dart b/pkg/dev_compiler/lib/src/analyzer/code_generator.dart
@@ -2844,7 +2844,7 @@ class CodeGenerator extends Object
             genFn);
       }
       gen.sourceInformation = _functionEnd(body);
-      if (JS.This.foundIn(gen)) gen = js.call('#.bind(this)', gen);
+      if (usesThisOrSuper(gen)) gen = js.call('#.bind(this)', gen);
 
       _superAllowed = savedSuperAllowed;
       _asyncStarController = savedController;
@@ -2922,14 +2922,9 @@ class CodeGenerator extends Object
     }
 
     var fn = _emitFunctionExpression(func.functionExpression);
-
     var name = _emitVariableDef(func.name);
     JS.Statement declareFn;
-    if (JS.This.foundIn(fn)) {
-      declareFn = js.statement('const # = #.bind(this);', [name, fn]);
-    } else {
-      declareFn = JS.FunctionDeclaration(name, fn);
-    }
+    declareFn = toBoundFunctionStatement(fn, name);
     var element = func.declaredElement;
     if (_reifyFunctionType(element)) {
       declareFn = JS.Block(

diff --git a/pkg/dev_compiler/lib/src/compiler/shared_compiler.dart b/pkg/dev_compiler/lib/src/compiler/shared_compiler.dart
@@ -606,3 +606,42 @@ class YieldFinder extends JS.BaseVisitor {
     super.visitNode(node);
   }
 }
+
+/// Given the function [fn], returns a function declaration statement, binding
+/// `this` and `super` if necessary (using an arrow function).
+JS.Statement toBoundFunctionStatement(JS.Fun fn, JS.Identifier name) {
+  if (usesThisOrSuper(fn)) {
+    return js.statement('const # = (#) => {#}', [name, fn.params, fn.body]);
+  } else {
+    return JS.FunctionDeclaration(name, fn);
+  }
+}
+
+/// Returns whether [node] uses `this` or `super`.
+bool usesThisOrSuper(JS.Expression node) {
+  var finder = _ThisOrSuperFinder.instance;
+  finder.found = false;
+  node.accept(finder);
+  return finder.found;
+}
+
+class _ThisOrSuperFinder extends JS.BaseVisitor<void> {
+  bool found = false;
+
+  static final instance = _ThisOrSuperFinder();
+
+  @override
+  visitThis(JS.This node) {
+    found = true;
+  }
+
+  @override
+  visitSuper(JS.Super node) {
+    found = true;
+  }
+
+  @override
+  visitNode(JS.Node node) {
+    if (!found) super.visitNode(node);
+  }
+}
diff --git a/pkg/dev_compiler/lib/src/js_ast/nodes.dart b/pkg/dev_compiler/lib/src/js_ast/nodes.dart
@@ -1189,27 +1189,6 @@ class This extends Expression {
   This _clone() => This();
   int get precedenceLevel => PRIMARY;
   void visitChildren(NodeVisitor visitor) {}
-
-  static bool foundIn(Node node) {
-    var finder = _ThisFinder._instance;
-    finder.found = false;
-    node.accept(finder);
-    return finder.found;
-  }
-}
-
-class _ThisFinder extends BaseVisitor<void> {
-  bool found = false;
-
-  static final _instance = _ThisFinder();
-
-  visitThis(This node) {
-    found = true;
-  }
-
-  visitNode(Node node) {
-    if (!found) super.visitNode(node);
-  }
 }
 
 // `super` is more restricted in the ES6 spec, but for simplicity we accept

diff --git a/pkg/dev_compiler/lib/src/kernel/compiler.dart b/pkg/dev_compiler/lib/src/kernel/compiler.dart
@@ -2718,7 +2718,7 @@ class ProgramCompiler extends Object
         }
 
         gen.sourceInformation = _nodeEnd(function.fileEndOffset);
-        if (JS.This.foundIn(gen)) gen = js.call('#.bind(this)', gen);
+        if (usesThisOrSuper(gen)) gen = js.call('#.bind(this)', gen);
       });
 
       _asyncStarController = savedController;
@@ -3569,11 +3569,7 @@ class ProgramCompiler extends Object
 
     var name = _emitVariableDef(node.variable);
     JS.Statement declareFn;
-    if (JS.This.foundIn(fn)) {
-      declareFn = js.statement('const # = #.bind(this);', [name, fn]);
-    } else {
-      declareFn = JS.FunctionDeclaration(name, fn);
-    }
+    declareFn = toBoundFunctionStatement(fn, name);
     if (_reifyFunctionType(func)) {
       declareFn = JS.Block([
         declareFn,