Standardize lifetime and type parameter count mismatch errors

They now always say how many lifetime / type parameters were expected
and are explicit about stating "lifetime" or "type" instead of just
"parameter".

Author: shepmaster

src/librustc_typeck/check/mod.rs

@@ -4510,28 +4510,32 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
             }
         };
 
-        let count = |n| {
-            format!("{} parameter{}", n, if n == 1 { "" } else { "s" })
+        let count_lifetime_params = |n| {
+            format!("{} lifetime parameter{}", n, if n == 1 { "" } else { "s" })
+        };
+        let count_type_params = |n| {
+            format!("{} type parameter{}", n, if n == 1 { "" } else { "s" })
         };
 
         // Check provided lifetime parameters.
         let lifetime_defs = segment.map_or(&[][..], |(_, generics)| &generics.regions);
         if lifetimes.len() > lifetime_defs.len() {
+            let expected_text = count_lifetime_params(lifetime_defs.len());
+            let actual_text = count_lifetime_params(lifetimes.len());
             struct_span_err!(self.tcx.sess, span, E0088,
                              "too many lifetime parameters provided: \
-                              expected {}, found {}",
-                              count(lifetime_defs.len()),
-                              count(lifetimes.len()))
-                .span_label(span, &format!("unexpected lifetime parameter{}",
-                                           match lifetimes.len() { 1 => "", _ => "s" }))
+                              expected at most {}, found {}",
+                             expected_text, actual_text)
+                .span_label(span, &format!("expected {}", expected_text))
                 .emit();
         } else if lifetimes.len() > 0 && lifetimes.len() < lifetime_defs.len() {
+            let expected_text = count_lifetime_params(lifetime_defs.len());
+            let actual_text = count_lifetime_params(lifetimes.len());
             struct_span_err!(self.tcx.sess, span, E0090,
                              "too few lifetime parameters provided: \
-                             expected {}, found {}",
-                             count(lifetime_defs.len()),
-                             count(lifetimes.len()))
-                .span_label(span, &format!("too few lifetime parameters"))
+                              expected {}, found {}",
+                             expected_text, actual_text)
+                .span_label(span, &format!("expected {}", expected_text))
                 .emit();
         }
 
@@ -4552,26 +4556,27 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                     .count();
         if types.len() > type_defs.len() {
             let span = types[type_defs.len()].span;
+            let expected_text = count_type_params(type_defs.len());
+            let actual_text = count_type_params(types.len());
             struct_span_err!(self.tcx.sess, span, E0087,
                              "too many type parameters provided: \
                               expected at most {}, found {}",
-                             count(type_defs.len()),
-                             count(types.len()))
-                .span_label(span, &format!("too many type parameters")).emit();
+                             expected_text, actual_text)
+                .span_label(span, &format!("expected {}", expected_text))
+                .emit();
 
             // To prevent derived errors to accumulate due to extra
             // type parameters, we force instantiate_value_path to
             // use inference variables instead of the provided types.
             *segment = None;
         } else if !infer_types && types.len() < required_len {
-            let adjust = |len| if len > 1 { "parameters" } else { "parameter" };
-            let required_param_str = adjust(required_len);
+            let expected_text = count_type_params(required_len);
+            let actual_text = count_type_params(types.len());
             struct_span_err!(self.tcx.sess, span, E0089,
                              "too few type parameters provided: \
                               expected {}, found {}",
-                             count(required_len),
-                             count(types.len()))
-                .span_label(span, &format!("expected {} type {}", required_len, required_param_str))
+                             expected_text, actual_text)
+                .span_label(span, &format!("expected {}", expected_text))
                 .emit();
         }
 

src/test/compile-fail/E0087.rs

@@ -8,9 +8,13 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-fn foo<T>() {}
+fn foo() {}
+fn bar<T>() {}
 
 fn main() {
-    foo::<f64, bool>(); //~ ERROR E0087
-    //~^ NOTE too many type parameters
+    foo::<f64>(); //~ ERROR expected at most 0 type parameters, found 1 type parameter [E0087]
+                  //~^ NOTE expected 0 type parameters
+
+    bar::<f64, u64>(); //~ ERROR expected at most 1 type parameter, found 2 type parameters [E0087]
+                       //~^ NOTE expected 1 type parameter
 }

src/test/compile-fail/E0088.rs

@@ -12,9 +12,11 @@ fn f() {}
 fn g<'a>() {}
 
 fn main() {
-    f::<'static>(); //~ ERROR E0088
-    //~^ unexpected lifetime parameter
+    f::<'static>();
+    //~^ ERROR expected at most 0 lifetime parameters, found 1 lifetime parameter [E0088]
+    //~| NOTE expected 0 lifetime parameters
 
-    g::<'static, 'static>(); //~ ERROR E0088
-    //~^ unexpected lifetime parameters
+    g::<'static, 'static>();
+    //~^ ERROR expected at most 0 lifetime parameters, found 2 lifetime parameters [E0088]
+    //~| NOTE expected 0 lifetime parameters
 }

src/test/compile-fail/E0089.rs

@@ -11,6 +11,6 @@
 fn foo<T, U>() {}
 
 fn main() {
-    foo::<f64>(); //~ ERROR expected 2 parameters, found 1 parameter [E0089]
+    foo::<f64>(); //~ ERROR expected 2 type parameters, found 1 type parameter [E0089]
                   //~| NOTE expected 2 type parameters
 }

src/test/compile-fail/E0090.rs

@@ -9,7 +9,8 @@
 // except according to those terms.
 
 fn foo<'a: 'b, 'b: 'a>() {}
+
 fn main() {
-    foo::<'static>();//~ ERROR E0090
-                     //~^ too few lifetime parameters
+    foo::<'static>(); //~ ERROR expected 2 lifetime parameters, found 1 lifetime parameter [E0090]
+                      //~^ NOTE expected 2 lifetime parameters
 }

src/test/compile-fail/ufcs-qpath-missing-params.rs

@@ -22,5 +22,5 @@ impl<'a> IntoCow<'a, str> for String {
 
 fn main() {
     <String as IntoCow>::into_cow("foo".to_string());
-    //~^ ERROR too few type parameters provided: expected 1 parameter
+    //~^ ERROR too few type parameters provided: expected 1 type parameter
 }