From @moritz

12​:11 <@​moritz_> rakudo​: class A { multi method b($x where { 0 } ) { }
}; A.new.b(4)
12​:11 <+p6eval> rakudo 92e914​: OUTPUT«No candidates found to invoke␤ in
main program body at line 11​:/tmp/jdOpy6exrT␤»
12​:13 * moritz_ submits rakudobug about LTA error message

It should mention at least​:
1) the name of the method
2) the type of the invocant

bonus points (and a beer at our next meeting) for listing candidates
like failed multi sub dispatch does it.

From @jnthn

On Sat Jun 19 03​:15​:52 2010, moritz wrote​:

12​:11 <@​moritz_> rakudo​: class A { multi method b($x where { 0 } ) { }
}; A.new.b(4)
12​:11 <+p6eval> rakudo 92e914​: OUTPUT«No candidates found to invoke␤ in
main program body at line 11​:/tmp/jdOpy6exrT␤»
12​:13 * moritz_ submits rakudobug about LTA error message

It should mention at least​:
1) the name of the method
2) the type of the invocant

bonus points (and a beer at our next meeting) for listing candidates
like failed multi sub dispatch does it.

So, taking a more interesting example​:

class A {
  multi method b($x) { 1 }
  multi method b($x, $y) { 2 }
}
say A.new.b();

Running this now gives the far, far more informative​:

No candidates found to invoke for method 'b' on object of type 'A';
available candidates have signatures​:
:(Mu : Any $x;; *%_)
:(Mu : Any $x, Any $y;; *%_)
  in main program body at line 5​:test.p6

Good enough for beer? ;-)

Given to moritz++ in case this is something that is testable or should
be tested.

Jonathan

The RT System itself - Status changed from 'new' to 'open'

@moritz - Status changed from 'open' to 'resolved'

From @kyleha

This is an automatically generated mail to inform you that tests are now available in t/spec/S12-methods/multi.t

commit 4b312a5186e94c35751ac9e57bd520cd5869ad49
Author​: moritz <moritz@​c213334d-75ef-0310-aa23-eaa082d1ae64>
Date​: Sun Jul 18 12​:17​:21 2010 +0000

  [t/spec] tests for RT #​75872, awesome error message when multi method dispatch finds no matching candidate
 
  Moritz ows jnthn++ a beer.
 
  git-svn-id​: http://svn.pugscode.org/pugs@&#8203;31746 c213334d-75ef-0310-aa23-eaa082d1ae64

diff --git a/t/spec/S12-methods/multi.t b/t/spec/S12-methods/multi.t
index 08e753f..5710b21 100644
--- a/t/spec/S12-methods/multi.t
+++ b/t/spec/S12-methods/multi.t
@@ -194,6 +194,16 @@ is Bar.new.a("not an Int"), 'Any-method in Foo';
 
     is WorkingTie.has_tie( 42 ), 'tie3', 'broken class fixed by subclass (1)';
     is WorkingTie.has_tie( 'x' ), 'tie4', 'broken class fixed by subclass (2)';
+
+    my $error;
+    try {
+        WorkingTie.new.has_tie([]);
+    }
+    $error = "$!";
+    ok $error ~~ /<< 'has_tie' >>/,
+        'error message for failed dispatch contains method name';
+    ok $error ~~ /<< 'WorkingTie' >>/,
+        'error message for failed dispatch contains invocant type';
 }
 
 done_testing;