Start to improve multi-method dispatch failure errors. Now they inclu…

…de the method name and the type name, which is somewhat awesomer, but not yet awesome.
rakudo · Jul 16, 2010 · c80d2d9 · c80d2d9
1 parent c2ebda4
commit c80d2d9
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Showing 2 changed files with 21 additions and 5 deletions.
diff --git a/src/glue/dispatch.pir b/src/glue/dispatch.pir
@@ -116,7 +116,9 @@ a failure if there is none.
     .local pmc exception
     .get_results (exception)
     pop_eh
-    if exception == "No candidates found to invoke" goto error
+    $S0 = exception
+    $S0 = substr $S0, 0, 29
+    if $S0 == "No candidates found to invoke" goto error
     rethrow exception
 
   error:
@@ -183,7 +185,9 @@ Implements the .* operator. Calls one or more matching methods.
     .local pmc exception
     .get_results (exception)
     pop_eh
-    if exception == "No candidates found to invoke" goto it_loop
+    $S0 = exception
+    $S0 = substr $S0, 0, 29
+    if $S0 == "No candidates found to invoke" goto it_loop
     rethrow exception
   it_loop_end:
 

diff --git a/src/pmc/p6invocation.pmc b/src/pmc/p6invocation.pmc
@@ -254,9 +254,21 @@ pmclass P6Invocation dynpmc group perl6_group auto_attrs {
             PMC *ns;
 
             /* Oh noes, no candidate. If we aren't in soft-fail mode, then
-             * throw an exception. */
-            if (!PObj_flag_TEST(P6I_FAILURE_MODE, SELF))
-                Parrot_ex_throw_from_c_args(interp, next, 1, "No candidates found to invoke");
+             * throw an exception with an informative error message. */
+            if (!PObj_flag_TEST(P6I_FAILURE_MODE, SELF)) {
+                STRING *method_name, *type_name;
+                PMC *WHAT, *perl_meth;
+                PMC *call_sig  = Parrot_pcc_get_signature(interp, CURRENT_CONTEXT(interp));
+                PMC *obj       = VTABLE_get_pmc_keyed_int(interp, call_sig, 0);
+                PMC *WHAT_meth = VTABLE_find_method(interp, obj, CONST_STRING(interp, "WHAT"));
+                Parrot_ext_call(interp, WHAT_meth, "Pi->P", obj, &WHAT);
+                perl_meth      = VTABLE_find_method(interp, WHAT, CONST_STRING(interp, "perl"));
+                Parrot_ext_call(interp, perl_meth, "Pi->S", WHAT, &type_name);
+                GETATTR_P6Invocation_name(interp, SELF, method_name);
+                Parrot_ex_throw_from_c_args(interp, next, 1,
+                    "No candidates found to invoke for method '%Ss' on object of type '%Ss'",
+                    method_name, type_name);
+            }
 
             /* Otherwise, we look up something that when invoked will just give a
              * dispatch failure. */