[Mono-dev] patch to fix CS0642 warning for if-else statement

[John Luke]

Hello,
I made an almost identical patch for bug 75745. If i remember right,
your error cs0642-7.cs should have an else clause
to test the error otherwise it is the same as cs0642.cs, and they should
all be at warning level 3 not 4.

Atsushi Eno wrote:

>Hi,
>
>I made a tiny patch for cs0642 warning (attached). It only fixes
>if-else statement cases. Will continue to fix #66777.
>
>I noticed that the use of EmptyStatement.Value hides the actual
>location to report. Basically using singleton is harmful for
>error reporting. Would it be bad idea if I replace all of them
>and create instance for each empty statements?
>
>Atsushi Eno
>  
>
>------------------------------------------------------------------------
>
>Index: mcs/cs-parser.jay
>===================================================================
>--- mcs/cs-parser.jay	(revision 48738)
>+++ mcs/cs-parser.jay	(working copy)
>@@ -3843,6 +3843,7 @@
> 		$$ = new If ((Expression) $3, (Statement) $5, l);
> 
> 		if (RootContext.WarningLevel >= 4){
>+			// FIXME: location for warning should be loc property of $5.
> 			if ($5 == EmptyStatement.Value)
> 				Report.Warning (642, l, "Possible mistaken empty statement");
> 		}
>@@ -3854,6 +3855,14 @@
> 		Location l = (Location) $1;
> 
> 		$$ = new If ((Expression) $3, (Statement) $5, (Statement) $7, l);
>+
>+		if (RootContext.WarningLevel >= 4){
>+			// FIXME: location for warning should be loc property of $5 and $7.
>+			if ($5 == EmptyStatement.Value)
>+				Report.Warning (642, l, "Possible mistaken empty statement");
>+			if ($7 == EmptyStatement.Value)
>+				Report.Warning (642, l, "Possible mistaken empty statement");
>+		}
> 	  }
> 	;
> 
>Index: errors/cs0642-7.cs
>===================================================================
>--- errors/cs0642-7.cs	(revision 0)
>+++ errors/cs0642-7.cs	(revision 0)
>@@ -0,0 +1,15 @@
>+// cs0642-7.cs : Possible mistaken empty statement
>+// Line: 11
>+// Compiler options: /warnaserror /warn:4
>+using System;
>+public class C
>+{
>+	public static int p = 0;
>+	public static void Foo ()
>+	{
>+		if (p < 5)
>+			;
>+		Console.WriteLine ();
>+	}
>+}
>+
>
>Property changes on: errors/cs0642-7.cs
>___________________________________________________________________
>Name: svn:eol-style
>   + native
>
>Index: errors/known-issues-mcs
>===================================================================
>--- errors/known-issues-mcs	(revision 48761)
>+++ errors/known-issues-mcs	(working copy)
>@@ -28,7 +28,6 @@
> cs0560.cs
> cs0567.cs
> cs0619-31.cs NO ERROR
>-cs0642.cs NO ERROR
> cs0642-2.cs NO ERROR
> cs0642-3.cs
> cs0642-4.cs
>Index: errors/cs0642-8.cs
>===================================================================
>--- errors/cs0642-8.cs	(revision 0)
>+++ errors/cs0642-8.cs	(revision 0)
>@@ -0,0 +1,17 @@
>+// cs0642-7.cs : Possible mistaken empty statement
>+// Line: 13
>+// Compiler options: /warnaserror /warn:4
>+using System;
>+public class C
>+{
>+	public static int p = 0;
>+	public static void Foo ()
>+	{
>+		if (p < 5)
>+			Console.WriteLine ();
>+		else
>+			;
>+		Console.WriteLine ();
>+	}
>+}
>+
>
>Property changes on: errors/cs0642-8.cs
>___________________________________________________________________
>Name: svn:eol-style
>   + native
>
>  
>
>------------------------------------------------------------------------
>
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>  
>