Fixup issues with dynamic angle bracket invocation.

packages/@glimmer/compiler/lib/template-compiler.ts

@@ -464,19 +464,21 @@ function isArg(path: AST.PathExpression): boolean {
 function isDynamicComponent(element: AST.ElementNode): boolean {
   let open = element.tag.charAt(0);
 
+  let [maybeLocal] = element.tag.split('.');
   let isNamedArgument = open === '@';
-  let isLocal = element['symbols'].has(element.tag);
-  let isPath = element.tag.indexOf('.') > -1;
+  let isLocal = element['symbols'].has(maybeLocal);
+  let isThisPath = element.tag.indexOf('this.') === 0;
 
-  return isLocal || isNamedArgument || isPath;
+  return isLocal || isNamedArgument || isThisPath;
 }
 
 function isComponent(element: AST.ElementNode): boolean {
   let open = element.tag.charAt(0);
+  let isPath = element.tag.indexOf('.') > -1;
 
   let isUpperCase = open === open.toUpperCase() && open !== open.toLowerCase();
 
-  return isUpperCase || isDynamicComponent(element);
+  return (isUpperCase && !isPath) || isDynamicComponent(element);
 }
 
 function assertIsSimplePath(path: AST.PathExpression, loc: AST.SourceLocation, context: string) {

packages/@glimmer/test-helpers/lib/suites/components.ts

@@ -181,6 +181,23 @@ export class BasicComponents extends RenderTest {
     this.assertStableRerender();
   }
 
+  @test({
+    kind: 'glimmer',
+  })
+  'invoking dynamic component (named arg path) via angle brackets'() {
+    this.registerHelper('hash', (_positional, named) => named);
+    this.registerComponent('Glimmer', 'Foo', 'hello world!');
+    this.render({
+      layout: '<@stuff.Foo />',
+      args: {
+        stuff: 'hash Foo=(component "Foo")',
+      },
+    });
+
+    this.assertHTML(`<div>hello world!</div>`);
+    this.assertStableRerender();
+  }
+
   @test({
     kind: 'glimmer',
   })
@@ -297,6 +314,18 @@ export class BasicComponents extends RenderTest {
     this.assertStableRerender();
   }
 
+  @test({
+    kind: 'glimmer',
+  })
+  'invoking dynamic component (local path) via angle brackets'() {
+    this.registerHelper('hash', (_positional, named) => named);
+    this.registerComponent('Glimmer', 'Foo', 'hello world!');
+    this.render(`{{#with (hash Foo=(component 'Foo')) as |Other|}}<Other.Foo />{{/with}}`);
+
+    this.assertHTML(`hello world!`);
+    this.assertStableRerender();
+  }
+
   @test({
     kind: 'glimmer',
   })
@@ -412,6 +441,37 @@ export class BasicComponents extends RenderTest {
     this.assertStableRerender();
   }
 
+  @test({
+    kind: 'glimmer',
+  })
+  'invoking dynamic component (path) via angle brackets does not support implicit `this` fallback'() {
+    class TestHarness extends EmberishGlimmerComponent {
+      public stuff: any;
+
+      constructor(args: any) {
+        super();
+        this.stuff = {
+          Foo: args.attrs.Foo,
+        };
+      }
+    }
+    this.registerComponent('Glimmer', 'TestHarness', '<stuff.Foo />', TestHarness);
+    this.registerComponent(
+      'Glimmer',
+      'Foo',
+      'hello world!',
+      class extends EmberishGlimmerComponent {
+        constructor() {
+          super(...arguments);
+          throw new Error('Should not have instantiated Foo component.');
+        }
+      }
+    );
+
+    this.render('<TestHarness @Foo={{component "Foo"}} />');
+    this.assertStableRerender();
+  }
+
   @test({
     kind: 'glimmer',
   })