Rollup merge of #35264 - GuillaumeGomez:E0132_update, r=jonathandturner

E0132 update

Fixes #35258.

r? @jonathandturner

src/librustc/hir/mod.rs

@@ -36,7 +36,7 @@ use hir::def::Def;
 use hir::def_id::DefId;
 use util::nodemap::{NodeMap, FnvHashSet};
 
-use syntax_pos::{mk_sp, Span, ExpnId};
+use syntax_pos::{BytePos, mk_sp, Span, ExpnId};
 use syntax::codemap::{self, respan, Spanned};
 use syntax::abi::Abi;
 use syntax::ast::{Name, NodeId, DUMMY_NODE_ID, AsmDialect};
@@ -326,6 +326,38 @@ impl Generics {
     pub fn is_parameterized(&self) -> bool {
         self.is_lt_parameterized() || self.is_type_parameterized()
     }
+
+    // Does return a span which includes lifetimes and type parameters,
+    // not where clause.
+    pub fn span(&self) -> Option<Span> {
+        if !self.is_parameterized() {
+            None
+        } else {
+            let mut span: Option<Span> = None;
+            for lifetime in self.lifetimes.iter() {
+                if let Some(ref mut span) = span {
+                    let life_span = lifetime.lifetime.span;
+                    span.hi = if span.hi > life_span.hi { span.hi } else { life_span.hi };
+                    span.lo = if span.lo < life_span.lo { span.lo } else { life_span.lo };
+                } else {
+                    span = Some(lifetime.lifetime.span.clone());
+                }
+            }
+            for ty_param in self.ty_params.iter() {
+                if let Some(ref mut span) = span {
+                    span.lo = if span.lo < ty_param.span.lo { span.lo } else { ty_param.span.lo };
+                    span.hi = if span.hi > ty_param.span.hi { span.hi } else { ty_param.span.hi };
+                } else {
+                    span = Some(ty_param.span.clone());
+                }
+            }
+            if let Some(ref mut span) = span {
+                span.lo = span.lo - BytePos(1);
+                span.hi = span.hi + BytePos(1);
+            }
+            span
+        }
+    }
 }
 
 /// A `where` clause in a definition

src/librustc_typeck/lib.rs

@@ -261,8 +261,11 @@ fn check_start_fn_ty(ccx: &CrateCtxt,
                     match it.node {
                         hir::ItemFn(_,_,_,_,ref ps,_)
                         if ps.is_parameterized() => {
-                            span_err!(tcx.sess, start_span, E0132,
-                                      "start function is not allowed to have type parameters");
+                            struct_span_err!(tcx.sess, start_span, E0132,
+                                "start function is not allowed to have type parameters")
+                                .span_label(ps.span().unwrap(),
+                                            &format!("start function cannot have type parameters"))
+                                .emit();
                             return;
                         }
                         _ => ()

src/test/compile-fail/E0132.rs

@@ -12,6 +12,7 @@
 
 #[start]
 fn f<T>() {} //~ ERROR E0132
+             //~| NOTE start function cannot have type parameters
 
 fn main() {
 }