Only suggest assoc fn when sure about the type

Author: estebank

src/librustc_typeck/check/method/suggest.rs

@@ -380,6 +380,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 if !static_sources.is_empty() {
                     err.note("found the following associated functions; to be used as methods, \
                               functions must have a `self` parameter");
+                }
+                if static_sources.len() == 1 {
                     if let Some(expr) = rcvr_expr {
                         err.span_suggestion(expr.span.to(span),
                                             "use associated function syntax intead",
@@ -389,6 +391,9 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                           self.ty_to_string(actual), item_name));
                     }
 
+                    report_candidates(&mut err, static_sources);
+                } else if static_sources.len() > 1 {
+
                     report_candidates(&mut err, static_sources);
                 }
 

src/test/ui/span/issue-7575.stderr

@@ -2,9 +2,7 @@ error[E0599]: no method named `f9` found for type `usize` in the current scope
   --> $DIR/issue-7575.rs:74:18
    |
 LL |     u.f8(42) + u.f9(342) + m.fff(42)
-   |                --^^
-   |                |
-   |                help: use associated function syntax intead: `usize::f9`
+   |                  ^^
    |
    = note: found the following associated functions; to be used as methods, functions must have a `self` parameter
 note: candidate #1 is defined in the trait `CtxtFn`
@@ -53,9 +51,7 @@ error[E0599]: no method named `is_str` found for type `T` in the current scope
   --> $DIR/issue-7575.rs:82:7
    |
 LL |     t.is_str()
-   |     --^^^^^^
-   |     |
-   |     help: use associated function syntax intead: `T::is_str`
+   |       ^^^^^^
    |
    = note: found the following associated functions; to be used as methods, functions must have a `self` parameter
 note: the candidate is defined in the trait `ManyImplTrait`