Catalog / Primitives / convert-to-block-body

Convert to Block Body

Replaces an expression body with a block holding the equivalent statement. The reverse of Convert to Expression Body.

Target

The declaration, by symbol: a method, constructor, operator, property, indexer or accessor (M:Sample.set_Name(System.String) for a setter). A local function, which has no symbol id, by a caret on its name.

Precondition

The declaration has an expression body.

Transformation

When the declaration returns a value, => expression; becomes { return expression; }: methods and local functions with a return type, operators, conversions and get accessors.
When it does not, the expression becomes a statement of its own: void methods, constructors, finalizers, set, init, add and remove accessors, and async methods returning Task or ValueTask, which await rather than return.
=> throw expression; becomes { throw expression; }.
An expression-bodied property or indexer gets an accessor list with a get accessor holding the block.
The block is laid out on lines of its own. An expression spanning several lines keeps its line breaks, shifted to sit under the statement.

Preserved

Behaviour: the block means exactly what the expression body did.
Comments above the declaration stay there; a comment after the semicolon stays at the end of the statement.

Limitations

An auto-property's accessors have no body to expand, and an abstract member none at all; both are refused.

Error codes

Code	Meaning
`already-block-body`	the declaration already has a block body
`no-body`	the declaration has no body, such as an abstract method or an auto-property
`not-a-member-with-body`	the target is not a method, property, accessor, constructor, operator or local function

Cases

Diffs show each file from before to after. /*[*/ … /*]*/ marks a selection and /*^*/ a caret; the runner removes them before the refactoring runs.

#accessor

One expression-bodied accessor gets a block; the other accessor is left alone

success

Targetsymbol M:Sample.set_Name(System.String)

Sample.csmodified

1	1		public class Sample
2	2		{
3	3		private string _name = "";
4	4
5	5		public string Name
6	6		{
7	7		get => _name;
8		−	set => _name = value.Trim();
	8	+	set
	9	+	{
	10	+	_name = value.Trim();
	11	+	}
9	12		}
10	13		}

1		public class Sample
2		{
3		private int _a;
4
5		public int Total()
6		{
7		return _a;
8		}
9		}

1	1		using System.Threading.Tasks;
2	2
3	3		public class Sample
4	4		{
5		−	public async Task SaveAsync() => await Task.Delay(10);
	5	+	public async Task SaveAsync()
	6	+	{
	7	+	await Task.Delay(10);
	8	+	}
6	9
7	10		public async Task<int> CountAsync() => await Task.FromResult(3);
8	11		}

1		public class Sample
2		{
3		public string Name { get; set; } = "";
4		}

1	1		namespace Shop;
2	2
3	3		public class Entity
4	4		{
5	5		}
6	6
7	7		public class Order : Entity
8	8		{
9	9		private readonly int _quantity;
10	10
11		−	public Order(int quantity) : base() => _quantity = quantity;
	11	+	public Order(int quantity) : base()
	12	+	{
	13	+	_quantity = quantity;
	14	+	}
12	15		}

1	1		public class Sample
2	2		{
3	3		private readonly int[] _items = new int[4];
4	4
5		−	public int this[int index] => _items[index];
	5	+	public int this[int index]
	6	+	{
	7	+	get
	8	+	{
	9	+	return _items[index];
	10	+	}
	11	+	}
6	12		}

1	1		public class Sample
2	2		{
3	3		private int _a;
4	4		private int _b;
5	5
6	6		/// <summary>The sum of both parts.</summary>
7		−	public int Total() => _a + _b; // unchecked
	7	+	public int Total()
	8	+	{
	9	+	return _a + _b; // unchecked
	10	+	}
8	11
9	12		public int Difference() => _a - _b;
10	13		}

1	1		public class Sample
2	2		{
3	3		public int Total(int[] prices)
4	4		{
5	5		var sum = 0;
6	6		foreach (var price in prices)
7	7		sum += WithTax(price);
8	8		return sum;
9	9
10		−	static int /^/WithTax(int price) => price * 120 / 100;
	10	+	static int WithTax(int price)
	11	+	{
	12	+	return price * 120 / 100;
	13	+	}
11	14		}
12	15		}

1	1		using System.Collections.Generic;
2	2		using System.Linq;
3	3
4	4		public class Sample
5	5		{
6		−	public int Total(List<int> items) => items
7		−	.Where(i => i > 0)
8		−	.Sum();
	6	+	public int Total(List<int> items)
	7	+	{
	8	+	return items
	9	+	.Where(i => i > 0)
	10	+	.Sum();
	11	+	}
9	12		}

1		public abstract class Shape
2		{
3		public abstract double Area();
4		}

1	1		using System.Collections.Generic;
2	2
3	3		public class Sample
4	4		{
5	5		private readonly Dictionary<string, string> _names = new();
6	6
7		−	public string? Find(string key) => _names.TryGetValue(key, out var name) ? name : null;
	7	+	public string? Find(string key)
	8	+	{
	9	+	return _names.TryGetValue(key, out var name) ? name : null;
	10	+	}
8	11		}

1	1		namespace Shop;
2	2
3	3		public readonly struct Money
4	4		{
5	5		public Money(decimal amount) => Amount = amount;
6	6
7	7		public decimal Amount { get; }
8	8
9		−	public static Money operator +(Money left, Money right) => new Money(left.Amount + right.Amount);
	9	+	public static Money operator +(Money left, Money right)
	10	+	{
	11	+	return new Money(left.Amount + right.Amount);
	12	+	}
10	13		}

1	1		using System;
2	2
3	3		public class Sample
4	4		{
5		−	public void Log(string message) => Console.WriteLine(message);
	5	+	public void Log(string message)
	6	+	{
	7	+	Console.WriteLine(message);
	8	+	}
6	9		}

1		public class Sample
2		{
3		private int _total;
4
5		public int Total => _total;
6		}

1	1		public class Sample
2	2		{
3	3		private string _first = "";
4	4		private string _last = "";
5	5
6		−	public string Name => _first + " " + _last;
	6	+	public string Name
	7	+	{
	8	+	get
	9	+	{
	10	+	return _first + " " + _last;
	11	+	}
	12	+	}
7	13		}

1	1		using System;
2	2
3	3		public class Sample
4	4		{
5		−	public int Next() => throw new NotSupportedException();
	5	+	public int Next()
	6	+	{
	7	+	throw new NotSupportedException();
	8	+	}
6	9		}

Convert to Block Body

Target

Precondition

Transformation

Preserved

Limitations

Error codes

Cases

#accessor

#already-block-body-rejected

#async-methods

#async-returning-value

#auto-property-rejected

#constructor

#indexer

#keeps-comments

#local-function

#multi-line-expression

#no-body-rejected

#not-a-member-rejected

#nullable-context

#operator

#read-only-property

#return-statement

#throw-expression

#void-method