issue-182. fixed throw expression

Author: shaark

lib/src/lints/prefer_early_return/visitors/prefer_early_return_visitor.dart

@@ -1,6 +1,7 @@
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:solid_lints/src/lints/prefer_early_return/visitors/return_statement_visitor.dart';
+import 'package:solid_lints/src/lints/prefer_early_return/visitors/throw_expression_visitor.dart';
 
 /// The AST visitor that will collect all unnecessary if statements
 class PreferEarlyReturnVisitor extends RecursiveAstVisitor<void> {
@@ -33,6 +34,7 @@ class PreferEarlyReturnVisitor extends RecursiveAstVisitor<void> {
     if (_isElseIfStatement(node)) return;
     if (_hasElseStatement(node)) return;
     if (_hasReturnStatement(node)) return;
+    if (_hasThrowExpression(node)) return;
 
     _nodes.add(node);
   }
@@ -70,4 +72,10 @@ class PreferEarlyReturnVisitor extends RecursiveAstVisitor<void> {
     node.accept(visitor);
     return visitor.nodes.isNotEmpty;
   }
+
+  bool _hasThrowExpression(Statement node) {
+    final visitor = ThrowExpressionVisitor();
+    node.accept(visitor);
+    return visitor.nodes.isNotEmpty;
+  }
 }

lib/src/lints/prefer_early_return/visitors/throw_expression_visitor.dart

@@ -0,0 +1,16 @@
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/visitor.dart';
+
+/// The AST visitor that will collect every Return statement
+class ThrowExpressionVisitor extends RecursiveAstVisitor<void> {
+  final _nodes = <ThrowExpression>[];
+
+  /// All unnecessary return statements
+  Iterable<ThrowExpression> get nodes => _nodes;
+
+  @override
+  void visitThrowExpression(ThrowExpression node) {
+    super.visitThrowExpression(node);
+    _nodes.add(node);
+  }
+}

lint_test/prefer_early_return_test.dart

@@ -235,3 +235,12 @@ void threeSeqentialIfReturn2() {
     _doSomething();
   }
 }
+
+void throwExpression() {
+  //no lint
+  if (true) {
+    throw '';
+  }
+
+  return;
+}