diff --git a/src/aurelia-validation.ts b/src/aurelia-validation.ts
index f5d8d47e..8c137770 100644
--- a/src/aurelia-validation.ts
+++ b/src/aurelia-validation.ts
@@ -3,7 +3,6 @@
 export * from './controller-validate-result';
 export * from './get-target-dom-element';
 export * from './property-info';
-export * from './property-accessor-parser';
 export * from './validate-binding-behavior';
 export * from './validate-event';
 export * from './validate-instruction';
@@ -30,7 +29,6 @@ import { Container } from 'aurelia-dependency-injection';
 import { Validator } from './validator';
 import { StandardValidator } from './implementation/standard-validator';
 import { ValidationMessageParser } from './implementation/validation-message-parser';
-import { PropertyAccessorParser } from './property-accessor-parser';
 import { ValidationRules } from './implementation/validation-rules';
 
 /**
@@ -65,8 +63,7 @@ export function configure(
   // the fluent rule definition API needs the parser to translate messages
   // to interpolation expressions.
   const messageParser = frameworkConfig.container.get(ValidationMessageParser);
-  const propertyParser = frameworkConfig.container.get(PropertyAccessorParser);
-  ValidationRules.initialize(messageParser, propertyParser);
+  ValidationRules.initialize(messageParser);
 
   // configure...
   const config = new AureliaValidationConfiguration();
diff --git a/src/implementation/validation-messages.ts b/src/implementation/validation-messages.ts
index 5ab8f831..19e36c59 100644
--- a/src/implementation/validation-messages.ts
+++ b/src/implementation/validation-messages.ts
@@ -29,7 +29,7 @@ export const validationMessages: ValidationMessages = {
 export class ValidationMessageProvider {
   public static inject = [ValidationMessageParser];
 
-  constructor(parser: ValidationMessageParser) { }
+  constructor(private parser: ValidationMessageParser) { }
 
   /**
    * Returns a message binding expression that corresponds to the key.
diff --git a/src/implementation/validation-rules.ts b/src/implementation/validation-rules.ts
index 2457f6e3..e6856028 100644
--- a/src/implementation/validation-rules.ts
+++ b/src/implementation/validation-rules.ts
@@ -2,7 +2,6 @@ import { Rule, RuleProperty, ValidationDisplayNameAccessor } from './rule';
 import { ValidationMessageParser } from './validation-message-parser';
 import { Rules } from './rules';
 import { validationMessages } from './validation-messages';
-import { PropertyAccessorParser, PropertyAccessor } from '../property-accessor-parser';
 import { isString } from '../util';
 
 /**
@@ -17,7 +16,7 @@ export class FluentRuleCustomizer<TObject, TValue> {
     config: object = {},
     private fluentEnsure: FluentEnsure<TObject>,
     private fluentRules: FluentRules<TObject, TValue>,
-    private parsers: Parsers
+    private messageParser: ValidationMessageParser
   ) {
     this.rule = {
       property,
@@ -55,7 +54,7 @@ export class FluentRuleCustomizer<TObject, TValue> {
    */
   public withMessage(message: string) {
     this.rule.messageKey = 'custom';
-    this.rule.message = this.parsers.message.parse(message);
+    this.rule.message = this.messageParser.parse(message);
     return this;
   }
 
@@ -84,8 +83,8 @@ export class FluentRuleCustomizer<TObject, TValue> {
    * Target a property with validation rules.
    * @param property The property to target. Can be the property name or a property accessor function.
    */
-  public ensure<TValue2>(subject: string | ((model: TObject) => TValue2)) {
-    return this.fluentEnsure.ensure<TValue2>(subject);
+  public ensure<TValue>(subject: keyof TObject) {
+    return this.fluentEnsure.ensure<TValue>(subject);
   }
 
   /**
@@ -217,7 +216,7 @@ export class FluentRules<TObject, TValue> {
 
   constructor(
     private fluentEnsure: FluentEnsure<TObject>,
-    private parsers: Parsers,
+    private messageParser: ValidationMessageParser,
     private property: RuleProperty
   ) { }
 
@@ -237,7 +236,7 @@ export class FluentRules<TObject, TValue> {
    */
   public satisfies(condition: (value: TValue, object?: TObject) => boolean | Promise<boolean>, config?: object) {
     return new FluentRuleCustomizer<TObject, TValue>(
-      this.property, condition, config, this.fluentEnsure, this, this.parsers);
+      this.property, condition, config, this.fluentEnsure, this, this.messageParser);
   }
 
   /**
@@ -357,21 +356,21 @@ export class FluentEnsure<TObject> {
    */
   public rules: Rule<TObject, any>[][] = [];
 
-  constructor(private parsers: Parsers) { }
+  constructor(private messageParser: ValidationMessageParser) { }
 
   /**
    * Target a property with validation rules.
    * @param property The property to target. Can be the property name or a property accessor
    * function.
    */
-  public ensure<TValue>(property: string | PropertyAccessor<TObject, TValue>) {
+  public ensure<TValue>(property: keyof TObject) {
     this.assertInitialized();
-    const name = this.parsers.property.parse(property);
+    const name = property as string;
     const fluentRules = new FluentRules<TObject, TValue>(
       this,
-      this.parsers,
+      this.messageParser,
       { name, displayName: null });
-    return this.mergeRules(fluentRules, name);
+    return this.mergeRules(fluentRules, property);
   }
 
   /**
@@ -380,7 +379,7 @@ export class FluentEnsure<TObject> {
   public ensureObject() {
     this.assertInitialized();
     const fluentRules = new FluentRules<TObject, TObject>(
-      this, this.parsers, { name: null, displayName: null });
+      this, this.messageParser, { name: null, displayName: null });
     return this.mergeRules(fluentRules, null);
   }
 
@@ -405,7 +404,7 @@ export class FluentEnsure<TObject> {
   }
 
   private assertInitialized() {
-    if (this.parsers) {
+    if (this.messageParser) {
       return;
     }
     throw new Error(`Did you forget to add ".plugin('aurelia-validation')" to your main.js?`);
@@ -428,28 +427,25 @@ export class FluentEnsure<TObject> {
  * Fluent rule definition API.
  */
 export class ValidationRules {
-  private static parsers: Parsers;
+  private static messageParser: ValidationMessageParser;
 
-  public static initialize(messageParser: ValidationMessageParser, propertyParser: PropertyAccessorParser) {
-    this.parsers = {
-      message: messageParser,
-      property: propertyParser
-    };
+  public static initialize(messageParser: ValidationMessageParser) {
+    this.messageParser = messageParser;
   }
 
   /**
    * Target a property with validation rules.
    * @param property The property to target. Can be the property name or a property accessor function.
    */
-  public static ensure<TObject, TValue>(property: string | PropertyAccessor<TObject, TValue>) {
-    return new FluentEnsure<TObject>(ValidationRules.parsers).ensure(property);
+  public static ensure<TObject>(property: keyof TObject) {
+    return new FluentEnsure<TObject>(ValidationRules.messageParser).ensure(property);
   }
 
   /**
    * Targets an object with validation rules.
    */
   public static ensureObject<TObject>() {
-    return new FluentEnsure<TObject>(ValidationRules.parsers).ensureObject();
+    return new FluentEnsure<TObject>(ValidationRules.messageParser).ensureObject();
   }
 
   /**
@@ -495,8 +491,3 @@ export class ValidationRules {
     Rules.unset(target);
   }
 }
-
-export interface Parsers {
-  message: ValidationMessageParser;
-  property: PropertyAccessorParser;
-}
diff --git a/src/property-accessor-parser.ts b/src/property-accessor-parser.ts
deleted file mode 100644
index 9bfc93ac..00000000
--- a/src/property-accessor-parser.ts
+++ /dev/null
@@ -1,39 +0,0 @@
-import {
-  Parser,
-  AccessMember,
-  AccessScope
-} from 'aurelia-binding';
-import { isString } from './util';
-
-export type PropertyAccessor<TObject, TValue> = (object: TObject) => TValue;
-
-export class PropertyAccessorParser {
-  public static inject = [Parser];
-
-  constructor(private parser: Parser) { }
-
-  public parse<TObject, TValue>(property: string | PropertyAccessor<TObject, TValue>): string {
-    if (isString(property)) {
-      return property as string;
-    }
-    const accessorText = getAccessorExpression(property.toString());
-    const accessor = this.parser.parse(accessorText);
-    if (accessor instanceof AccessScope
-      || accessor instanceof AccessMember && accessor.object instanceof AccessScope) {
-      return accessor.name;
-    }
-    throw new Error(`Invalid property expression: "${accessor}"`);
-  }
-}
-
-export function getAccessorExpression(fn: string): string {
-  /* tslint:disable:max-line-length */
-  const classic = /^function\s*\([$_\w\d]+\)\s*\{(?:\s*"use strict";)?\s*(?:[$_\w\d.['"\]+;]+)?\s*return\s+[$_\w\d]+\.([$_\w\d]+)\s*;?\s*\}$/;
-  /* tslint:enable:max-line-length */
-  const arrow = /^\(?[$_\w\d]+\)?\s*=>\s*[$_\w\d]+\.([$_\w\d]+)$/;
-  const match = classic.exec(fn) || arrow.exec(fn);
-  if (match === null) {
-    throw new Error(`Unable to parse accessor function:\n${fn}`);
-  }
-  return match[1];
-}
diff --git a/src/validation-controller-factory.ts b/src/validation-controller-factory.ts
index 15a25ba9..de763b80 100644
--- a/src/validation-controller-factory.ts
+++ b/src/validation-controller-factory.ts
@@ -1,7 +1,6 @@
 import { Container } from 'aurelia-dependency-injection';
 import { ValidationController } from './validation-controller';
 import { Validator } from './validator';
-import { PropertyAccessorParser } from './property-accessor-parser';
 
 /**
  * Creates ValidationController instances.
@@ -20,8 +19,7 @@ export class ValidationControllerFactory {
     if (!validator) {
       validator = this.container.get(Validator) as Validator;
     }
-    const propertyParser = this.container.get(PropertyAccessorParser) as PropertyAccessorParser;
-    return new ValidationController(validator, propertyParser);
+    return new ValidationController(validator);
   }
 
   /**
diff --git a/src/validation-controller.ts b/src/validation-controller.ts
index 9ef46acb..adab3942 100644
--- a/src/validation-controller.ts
+++ b/src/validation-controller.ts
@@ -6,7 +6,6 @@ import { ValidationRenderer, RenderInstruction } from './validation-renderer';
 import { ValidateResult } from './validate-result';
 import { ValidateInstruction } from './validate-instruction';
 import { ControllerValidateResult } from './controller-validate-result';
-import { PropertyAccessorParser, PropertyAccessor } from './property-accessor-parser';
 import { ValidateEvent } from './validate-event';
 
 /**
@@ -15,7 +14,7 @@ import { ValidateEvent } from './validate-event';
  * Exposes the current list of validation results for binding purposes.
  */
 export class ValidationController {
-  public static inject = [Validator, PropertyAccessorParser];
+  public static inject = [Validator];
 
   // Registered bindings (via the validate binding behavior)
   private bindings = new Map<Binding, BindingInfo>();
@@ -54,7 +53,7 @@ export class ValidationController {
 
   private eventCallbacks: ((event: ValidateEvent) => void)[] = [];
 
-  constructor(private validator: Validator, private propertyParser: PropertyAccessorParser) { }
+  constructor(private validator: Validator) { }
 
   /**
    * Subscribe to controller validate and reset events. These events occur when the
@@ -101,15 +100,9 @@ export class ValidationController {
   public addError<TObject>(
     message: string,
     object: TObject,
-    propertyName: string | PropertyAccessor<TObject, string> | null = null
+    propertyName: string | null = null
   ): ValidateResult {
-    let resolvedPropertyName: string | null;
-    if (propertyName === null) {
-      resolvedPropertyName = propertyName;
-    } else {
-      resolvedPropertyName = this.propertyParser.parse(propertyName);
-    }
-    const result = new ValidateResult({ __manuallyAdded__: true }, object, resolvedPropertyName, false, message);
+    const result = new ValidateResult({ __manuallyAdded__: true }, object, propertyName, false, message);
     this.processResultDelta('validate', [], [result]);
     return result;
   }
diff --git a/test/basic.ts b/test/basic.ts
index b4e7a2a4..d62882f5 100644
--- a/test/basic.ts
+++ b/test/basic.ts
@@ -190,20 +190,13 @@ describe('end to end', () => {
         expect(error2.message).toBe('string property error');
         expect(error2.object).toBe(viewModel);
         expect(error2.propertyName).toBe('lastName');
-        const error3 = viewModel.controller.addError('expression property error', viewModel, vm => vm.firstName);
-        expect(error3.message).toBe('expression property error');
-        expect(error3.object).toBe(viewModel);
-        expect(error3.propertyName).toBe('firstName');
 
-        expect(viewModel.controller.errors.length).toBe(3);
-
-        viewModel.controller.removeError(error1);
         expect(viewModel.controller.errors.length).toBe(2);
 
-        viewModel.controller.removeError(error2);
+        viewModel.controller.removeError(error1);
         expect(viewModel.controller.errors.length).toBe(1);
 
-        viewModel.controller.removeError(error3);
+        viewModel.controller.removeError(error2);
         expect(viewModel.controller.errors.length).toBe(0);
       })
       // subscribe to error events
diff --git a/test/property-accessor-parser.ts b/test/property-accessor-parser.ts
deleted file mode 100644
index ed0d2723..00000000
--- a/test/property-accessor-parser.ts
+++ /dev/null
@@ -1,52 +0,0 @@
-import { Container } from 'aurelia-dependency-injection';
-import { BindingLanguage } from 'aurelia-templating';
-import { TemplatingBindingLanguage } from 'aurelia-templating-binding';
-import {
-  PropertyAccessorParser,
-  getAccessorExpression as parse
-} from '../src/aurelia-validation';
-
-describe('PropertyAccessorParser', () => {
-  let parser: PropertyAccessorParser;
-
-  beforeAll(() => {
-    const container = new Container();
-    container.registerInstance(BindingLanguage, container.get(TemplatingBindingLanguage));
-    parser = container.get(PropertyAccessorParser);
-  });
-
-  it('parses properties', () => {
-    expect(parser.parse('firstName')).toEqual('firstName');
-    expect(parser.parse('3_letter_id')).toEqual('3_letter_id');
-    expect(parser.parse('. @$# ???')).toEqual('. @$# ???');
-    expect(parser.parse((x: any) => x.firstName)).toEqual('firstName');
-  });
-
-  it('parses function bodies', () => {
-    expect(parse('function(a){return a.b}')).toEqual('b');
-    expect(parse('function(a){return a.b;}')).toEqual('b');
-    expect(parse('function (a){return a.b;}')).toEqual('b');
-    expect(parse('function(a) {return a.b;}')).toEqual('b');
-    expect(parse('function (a) { return a.b; }')).toEqual('b');
-    expect(parse('function (a1) { return a1.bcde; }')).toEqual('bcde');
-    expect(parse('function ($a1) { return $a1.bcde; }')).toEqual('bcde');
-    expect(parse('function (_) { return _.bc_de; }')).toEqual('bc_de');
-    expect(parse('function (a) {"use strict"; return a.b; }')).toEqual('b');
-    expect(parse('function (a) { "use strict";  return a.b; }')).toEqual('b');
-    expect(parse('a=>a.b')).toEqual('b');
-    expect(parse('a =>a.b')).toEqual('b');
-    expect(parse('a=> a.b')).toEqual('b');
-    expect(parse('a => a.b')).toEqual('b');
-    expect(parse('a => a.bcde')).toEqual('bcde');
-    expect(parse('_ => _.b')).toEqual('b');
-    expect(parse('$ => $.b')).toEqual('b');
-    expect(parse('(x) => x.name')).toEqual('name');
-
-    // tslint:disable-next-line:max-line-length
-    expect(parse('function(a){__gen$field.f[\'10\']++;__aGen$field.g[\'10\']++;return a.b;}'))
-      .toEqual('b');
-    // tslint:disable-next-line:max-line-length
-    expect(parse('function(a){"use strict";_gen$field.f[\'10\']++;_aGen$field.g[\'10\']++;return a.b;}'))
-      .toEqual('b');
-  });
-});
diff --git a/test/resources/nullable-object-form.ts b/test/resources/nullable-object-form.ts
index 45fcd0b6..09ec6f98 100644
--- a/test/resources/nullable-object-form.ts
+++ b/test/resources/nullable-object-form.ts
@@ -27,7 +27,7 @@ export class NullableObjectForm {
     console.log(value);
   }
 
-  public rules = ValidationRules.ensure('prop').required().rules as any;
+  public rules = ValidationRules.ensure<any>('prop').required().rules as any;
 
   constructor(public controller: ValidationController) { }
 }
diff --git a/test/resources/registration-form.ts b/test/resources/registration-form.ts
index 8724724a..121f940f 100644
--- a/test/resources/registration-form.ts
+++ b/test/resources/registration-form.ts
@@ -51,11 +51,12 @@ ValidationRules.customRule(
 );
 
 ValidationRules
-  .ensure((f: RegistrationForm) => f.firstName).required()
-  .ensure(f => f.lastName).required()
-  .ensure('email').required().email()
-  .ensure(f => f.number1).satisfies(value => value > 0)
-  .ensure(f => f.number2).satisfies(value => value > 0).withMessage('${displayName} gots to be greater than zero.')
-  .ensure(f => f.password).required()
-  .ensure(f => f.confirmPassword).required().satisfiesRule('matchesProperty', 'password')
+  .ensure<RegistrationForm>('firstName').required()
+  .ensure<RegistrationForm>('lastName').required()
+  .ensure<RegistrationForm>('email').required().email()
+  .ensure<RegistrationForm>('number1').satisfies(value => value > 0)
+  .ensure<RegistrationForm>('number2').satisfies(value => value > 0)
+    .withMessage('${displayName} gots to be greater than zero.')
+  .ensure<RegistrationForm>('password').required()
+  .ensure<RegistrationForm>('confirmPassword').required().satisfiesRule('matchesProperty', 'password')
   .on(RegistrationForm);
diff --git a/test/resources/trigger-form.ts b/test/resources/trigger-form.ts
index 4df83bfd..8c34e01b 100644
--- a/test/resources/trigger-form.ts
+++ b/test/resources/trigger-form.ts
@@ -34,9 +34,9 @@ export class TriggerForm {
 }
 
 ValidationRules
-  .ensure((f: TriggerForm) => f.standardProp).required()
-  .ensure(f => f.blurProp).required()
-  .ensure(f => f.changeProp).required()
-  .ensure(f => f.changeOrBlurProp).required()
-  .ensure(f => f.manualProp).required()
+  .ensure<TriggerForm>('standardProp').required()
+  .ensure<TriggerForm>('blurProp').required()
+  .ensure<TriggerForm>('changeProp').required()
+  .ensure<TriggerForm>('changeOrBlurProp').required()
+  .ensure<TriggerForm>('manualProp').required()
   .on(TriggerForm);
diff --git a/test/resources/validation-errors-form-one.ts b/test/resources/validation-errors-form-one.ts
index fd8b950f..be2739e9 100644
--- a/test/resources/validation-errors-form-one.ts
+++ b/test/resources/validation-errors-form-one.ts
@@ -36,5 +36,5 @@ export class ValidationErrorsFormOne {
 }
 
 ValidationRules
-  .ensure((f: ValidationErrorsFormOne) => f.standardProp).required()
+  .ensure<ValidationErrorsFormOne>('standardProp').required()
   .on(ValidationErrorsFormOne);
diff --git a/test/server.ts b/test/server.ts
index 2589be4d..c71c0977 100644
--- a/test/server.ts
+++ b/test/server.ts
@@ -15,8 +15,8 @@ configureBindingLanguage({ container });
 configureValidation({ container });
 
 const rules = ValidationRules
-  .ensure('firstName').required()
-  .ensure('lastName').required()
+  .ensure<any>('firstName').required()
+  .ensure<any>('lastName').required()
   .rules;
 
 const validator: Validator = container.get(Validator);
diff --git a/test/validator.ts b/test/validator.ts
index 5a0357a6..191269f2 100644
--- a/test/validator.ts
+++ b/test/validator.ts
@@ -6,7 +6,6 @@ import {
   ValidationRules,
   ValidationMessageParser,
   ValidateResult,
-  PropertyAccessorParser
 } from '../src/aurelia-validation';
 
 describe('Validator', () => {
@@ -16,14 +15,13 @@ describe('Validator', () => {
     const container = new Container();
     container.registerInstance(BindingLanguage, container.get(TemplatingBindingLanguage));
     const messageParser = container.get(ValidationMessageParser);
-    const propertyParser = container.get(PropertyAccessorParser);
-    ValidationRules.initialize(messageParser, propertyParser);
+    ValidationRules.initialize(messageParser);
     validator = container.get(StandardValidator);
   });
 
   it('validates email', (done: () => void) => {
     let obj = { prop: 'foo@bar.com' as any };
-    let rules = ValidationRules.ensure('prop').email().rules;
+    let rules = ValidationRules.ensure<any>('prop').email().rules;
     validator.validateProperty(obj, 'prop', rules)
       .then(results => {
         const expected = [new ValidateResult(rules[0][0], obj, 'prop', true, null)];
@@ -32,7 +30,7 @@ describe('Validator', () => {
       })
       .then(() => {
         obj = { prop: 'foo' };
-        rules = ValidationRules.ensure('prop').email().rules;
+        rules = ValidationRules.ensure<any>('prop').email().rules;
         return validator.validateProperty(obj, 'prop', rules);
       })
       .then(results => {
@@ -42,7 +40,7 @@ describe('Validator', () => {
       })
       .then(() => {
         obj = { prop: null };
-        rules = ValidationRules.ensure('prop').email().rules;
+        rules = ValidationRules.ensure<any>('prop').email().rules;
         return validator.validateProperty(obj, 'prop', rules);
       })
       .then(results => {
@@ -55,7 +53,7 @@ describe('Validator', () => {
 
   it('validates equals', (done: () => void) => {
     let obj = { prop: 'test' as any };
-    let rules = ValidationRules.ensure('prop').equals('test').rules;
+    let rules = ValidationRules.ensure<any>('prop').equals('test').rules;
     validator.validateProperty(obj, 'prop', rules)
       .then(results => {
         const expected = [new ValidateResult(rules[0][0], obj, 'prop', true, null)];
@@ -64,7 +62,7 @@ describe('Validator', () => {
       })
       .then(() => {
         obj = { prop: 'foo' };
-        rules = ValidationRules.ensure('prop').equals('test').rules;
+        rules = ValidationRules.ensure<any>('prop').equals('test').rules;
         return validator.validateProperty(obj, 'prop', rules);
       })
       .then(results => {
@@ -74,7 +72,7 @@ describe('Validator', () => {
       })
       .then(() => {
         obj = { prop: null };
-        rules = ValidationRules.ensure('prop').equals('test').rules;
+        rules = ValidationRules.ensure<any>('prop').equals('test').rules;
         return validator.validateProperty(obj, 'prop', rules);
       })
       .then(results => {
@@ -90,7 +88,7 @@ describe('Validator', () => {
     const spy1 = jasmine.createSpy().and.returnValue(true);
     const spy2 = jasmine.createSpy().and.returnValue(true);
     const rules = ValidationRules
-      .ensure('prop').email().then().satisfies(spy1)
+      .ensure<any>('prop').email().then().satisfies(spy1)
       .ensure('prop2').satisfies(spy2)
       .rules;
     validator.validateProperty(obj, 'prop', rules)