librustc_typeck: give more information when supplied wrong number of type-params for methods

src/librustc_typeck/check/method/confirm.rs

@@ -351,7 +351,8 @@ fn instantiate_method_substs(&mut self,
                 method_types);
         } else if num_supplied_types != num_method_types {
             span_err!(self.tcx().sess, self.span, E0036,
-                "incorrect number of type parameters given for this method");
+                "incorrect number of type parameters given for this method: expected {}, found {}",
+                num_method_types, num_supplied_types);
             final_substs.types.replace(
                 subst::FnSpace,
                 vec![self.tcx().types.err; num_method_types]);

src/test/compile-fail/trait-test-2.rs

@@ -16,7 +16,8 @@ impl bar for u32 { fn dup(&self) -> u32 { *self } fn blah<X>(&self) {} }
 
 fn main() {
     10.dup::<i32>(); //~ ERROR does not take type parameters
-    10.blah::<i32, i32>(); //~ ERROR incorrect number of type parameters
+    10.blah::<i32, i32>();
+    //~^ ERROR incorrect number of type parameters given for this method: expected 1, found 2
     (box 10 as Box<bar>).dup();
     //~^ ERROR E0038
     //~| ERROR E0038