From 0e3c7b6a8221895c53f7e61593ef8560ce5df117 Mon Sep 17 00:00:00 2001
From: arusakov <a_s_rusakov@mail.ru>
Date: Mon, 20 Feb 2017 01:08:53 +0300
Subject: [PATCH 1/2] no-non-null-assertion rule

---
 src/language/walker/syntaxWalker.ts           |  8 ++++
 src/rules/noNonNullAssertionRule.ts           | 47 +++++++++++++++++++
 test/rules/no-non-null-assertion/test.ts.lint |  4 ++
 test/rules/no-non-null-assertion/tslint.json  |  5 ++
 4 files changed, 64 insertions(+)
 create mode 100644 src/rules/noNonNullAssertionRule.ts
 create mode 100644 test/rules/no-non-null-assertion/test.ts.lint
 create mode 100644 test/rules/no-non-null-assertion/tslint.json

diff --git a/src/language/walker/syntaxWalker.ts b/src/language/walker/syntaxWalker.ts
index acee72b0e09..09d22289810 100644
--- a/src/language/walker/syntaxWalker.ts
+++ b/src/language/walker/syntaxWalker.ts
@@ -234,6 +234,10 @@ export class SyntaxWalker {
         this.walkChildren(node);
     }
 
+    protected visitNonNullExpression(node: ts.NonNullExpression) {
+        this.walkChildren(node);
+    }
+
     protected visitNumericLiteral(node: ts.NumericLiteral) {
         this.walkChildren(node);
     }
@@ -560,6 +564,10 @@ export class SyntaxWalker {
                 this.visitNewExpression(node as ts.NewExpression);
                 break;
 
+            case ts.SyntaxKind.NonNullExpression:
+                this.visitNonNullExpression(node as ts.NonNullExpression);
+                break;
+
             case ts.SyntaxKind.NumericLiteral:
                 this.visitNumericLiteral(node as ts.NumericLiteral);
                 break;
diff --git a/src/rules/noNonNullAssertionRule.ts b/src/rules/noNonNullAssertionRule.ts
new file mode 100644
index 00000000000..1fa1b6f80d9
--- /dev/null
+++ b/src/rules/noNonNullAssertionRule.ts
@@ -0,0 +1,47 @@
+/**
+ * @license
+ * Copyright 2013 Palantir Technologies, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import * as ts from "typescript";
+
+import * as Lint from "../index";
+
+export class Rule extends Lint.Rules.AbstractRule {
+    /* tslint:disable:object-literal-sort-keys */
+    public static metadata: Lint.IRuleMetadata = {
+        ruleName: "no-non-null-assertion",
+        description: "Disallows non null assertions.",
+        optionsDescription: "Not configurable.",
+        options: null,
+        optionExamples: ["true"],
+        type: "typescript",
+        typescriptOnly: true,
+    };
+    /* tslint:enable:object-literal-sort-keys */
+
+    public static FAILURE_STRING = "Forbidden non null assertion";
+
+    public apply(sourceFile: ts.SourceFile): Lint.RuleFailure[] {
+        return this.applyWithWalker(new NoNonNullAssertionWalker(sourceFile, this.getOptions()));
+    }
+}
+
+class NoNonNullAssertionWalker extends Lint.RuleWalker {
+    public visitNonNullExpression(node: ts.NonNullExpression) {
+        this.addFailureAtNode(node, Rule.FAILURE_STRING);
+        super.visitNonNullExpression(node);
+    }
+}
diff --git a/test/rules/no-non-null-assertion/test.ts.lint b/test/rules/no-non-null-assertion/test.ts.lint
new file mode 100644
index 00000000000..12bb8af725d
--- /dev/null
+++ b/test/rules/no-non-null-assertion/test.ts.lint
@@ -0,0 +1,4 @@
+var x = null
+
+x!.y = null
+~~          [Forbidden non null assertion]
diff --git a/test/rules/no-non-null-assertion/tslint.json b/test/rules/no-non-null-assertion/tslint.json
new file mode 100644
index 00000000000..6359b34ac55
--- /dev/null
+++ b/test/rules/no-non-null-assertion/tslint.json
@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "no-non-null-assertion": true
+  }
+}

From a433216ca6e99dc7d14076519422ad41a29b9a20 Mon Sep 17 00:00:00 2001
From: arusakov <a_s_rusakov@mail.ru>
Date: Wed, 22 Feb 2017 01:05:16 +0300
Subject: [PATCH 2/2] copyright year fixed, rationale added

---
 src/rules/noNonNullAssertionRule.ts | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/rules/noNonNullAssertionRule.ts b/src/rules/noNonNullAssertionRule.ts
index 1fa1b6f80d9..015f3bdcbea 100644
--- a/src/rules/noNonNullAssertionRule.ts
+++ b/src/rules/noNonNullAssertionRule.ts
@@ -1,6 +1,6 @@
 /**
  * @license
- * Copyright 2013 Palantir Technologies, Inc.
+ * Copyright 2017 Palantir Technologies, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,7 +23,8 @@ export class Rule extends Lint.Rules.AbstractRule {
     /* tslint:disable:object-literal-sort-keys */
     public static metadata: Lint.IRuleMetadata = {
         ruleName: "no-non-null-assertion",
-        description: "Disallows non null assertions.",
+        description: "Disallows non-null assertions.",
+        rationale: "Using non-null assertion cancels the benefits of the strict null checking mode.",
         optionsDescription: "Not configurable.",
         options: null,
         optionExamples: ["true"],