Point at local similarly named element and tweak references to variants

Point at the span for the definition of ADTs internal to the current
crate.

Look at the leading char of the ident to determine whether we're
expecting a likely fn or any of a fn, a tuple struct or a tuple variant.

Turn fn `add_typo_suggestion` into a `Resolver` method.

Author: estebank

src/librustc_resolve/build_reduced_graph.rs

@@ -850,12 +850,14 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
             Res::Def(kind @ DefKind::Mod, def_id)
             | Res::Def(kind @ DefKind::Enum, def_id)
             | Res::Def(kind @ DefKind::Trait, def_id) => {
-                let module = self.r.new_module(parent,
-                                             ModuleKind::Def(kind, def_id, ident.name),
-                                             def_id,
-                                             expansion,
-                                             span);
-                self.r.define(parent, ident, TypeNS, (module, vis, DUMMY_SP, expansion));
+                let module = self.r.new_module(
+                    parent,
+                    ModuleKind::Def(kind, def_id, ident.name),
+                    def_id,
+                    expansion,
+                    span,
+                );
+                self.r.define(parent, ident, TypeNS, (module, vis, span, expansion));
             }
             Res::Def(DefKind::Struct, _)
             | Res::Def(DefKind::Union, _)
@@ -868,17 +870,17 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
             | Res::Def(DefKind::AssocOpaqueTy, _)
             | Res::PrimTy(..)
             | Res::ToolMod =>
-                self.r.define(parent, ident, TypeNS, (res, vis, DUMMY_SP, expansion)),
+                self.r.define(parent, ident, TypeNS, (res, vis, span, expansion)),
             Res::Def(DefKind::Fn, _)
             | Res::Def(DefKind::Method, _)
             | Res::Def(DefKind::Static, _)
             | Res::Def(DefKind::Const, _)
             | Res::Def(DefKind::AssocConst, _)
             | Res::Def(DefKind::Ctor(..), _) =>
-                self.r.define(parent, ident, ValueNS, (res, vis, DUMMY_SP, expansion)),
+                self.r.define(parent, ident, ValueNS, (res, vis, span, expansion)),
             Res::Def(DefKind::Macro(..), _)
             | Res::NonMacroAttr(..) =>
-                self.r.define(parent, ident, MacroNS, (res, vis, DUMMY_SP, expansion)),
+                self.r.define(parent, ident, MacroNS, (res, vis, span, expansion)),
             Res::Def(DefKind::TyParam, _) | Res::Def(DefKind::ConstParam, _)
             | Res::Local(..) | Res::SelfTy(..) | Res::SelfCtor(..) | Res::Err =>
                 bug!("unexpected resolution: {:?}", res)

src/librustc_resolve/diagnostics.rs

@@ -58,21 +58,6 @@ fn reduce_impl_span_to_impl_keyword(cm: &SourceMap, impl_span: Span) -> Span {
     impl_span
 }
 
-crate fn add_typo_suggestion(
-    err: &mut DiagnosticBuilder<'_>, suggestion: Option<TypoSuggestion>, span: Span
-) -> bool {
-    if let Some(suggestion) = suggestion {
-        let msg = format!(
-            "{} {} with a similar name exists", suggestion.res.article(), suggestion.res.descr()
-        );
-        err.span_suggestion(
-            span, &msg, suggestion.candidate.to_string(), Applicability::MaybeIncorrect
-        );
-        return true;
-    }
-    false
-}
-
 impl<'a> Resolver<'a> {
     crate fn add_module_candidates(
         &mut self,
@@ -641,7 +626,7 @@ impl<'a> Resolver<'a> {
         let suggestion = self.early_lookup_typo_candidate(
             ScopeSet::Macro(macro_kind), parent_scope, ident, is_expected
         );
-        add_typo_suggestion(err, suggestion, ident.span);
+        self.add_typo_suggestion(err, suggestion, ident.span);
 
         if macro_kind == MacroKind::Derive &&
            (ident.as_str() == "Send" || ident.as_str() == "Sync") {
@@ -652,6 +637,33 @@ impl<'a> Resolver<'a> {
             err.help("have you added the `#[macro_use]` on the module/import?");
         }
     }
+
+    crate fn add_typo_suggestion(
+        &self,
+        err: &mut DiagnosticBuilder<'_>,
+        suggestion: Option<TypoSuggestion>,
+        span: Span,
+    ) -> bool {
+        if let Some(suggestion) = suggestion {
+            let msg = format!(
+                "{} {} with a similar name exists", suggestion.res.article(), suggestion.res.descr()
+            );
+            err.span_suggestion(
+                span, &msg, suggestion.candidate.to_string(), Applicability::MaybeIncorrect
+            );
+            let def_span = suggestion.res.opt_def_id()
+                .and_then(|def_id| self.definitions.opt_span(def_id));
+            if let Some(span) = def_span {
+                err.span_label(span, &format!(
+                    "similarly named {} `{}` defined here",
+                    suggestion.res.descr(),
+                    suggestion.candidate.as_str(),
+                ));
+            }
+            return true;
+        }
+        false
+    }
 }
 
 impl<'a, 'b> ImportResolver<'a, 'b> {

src/librustc_resolve/error_codes.rs

@@ -974,7 +974,7 @@ function:
 struct Foo { a: bool };
 
 let f = Foo();
-// error: expected function, found `Foo`
+// error: expected function, tuple struct or tuple variant, found `Foo`
 // `Foo` is a struct name, but this expression uses it like a function name
 ```
 
@@ -992,7 +992,8 @@ yield this error:
 
 ```compile_fail,E0423
 println("");
-// error: expected function, found macro `println`
+// error: expected function, tuple struct or tuple variant,
+// found macro `println`
 // did you mean `println!(...)`? (notice the trailing `!`)
 ```
 
@@ -1592,7 +1593,7 @@ enum State {
 
 fn print_on_failure(state: &State) {
     match *state {
-        // error: expected unit struct/variant or constant, found tuple
+        // error: expected unit struct, unit variant or constant, found tuple
         //        variant `State::Failed`
         State::Failed => println!("Failed"),
         _ => ()

src/librustc_resolve/late.rs

@@ -199,21 +199,36 @@ impl<'a> PathSource<'a> {
     }
 
     fn descr_expected(self) -> &'static str {
-        match self {
+        match &self {
             PathSource::Type => "type",
             PathSource::Trait(_) => "trait",
-            PathSource::Pat => "unit struct/variant or constant",
+            PathSource::Pat => "unit struct, unit variant or constant",
             PathSource::Struct => "struct, variant or union type",
-            PathSource::TupleStruct => "tuple struct/variant",
+            PathSource::TupleStruct => "tuple struct or tuple variant",
             PathSource::TraitItem(ns) => match ns {
                 TypeNS => "associated type",
                 ValueNS => "method or associated constant",
                 MacroNS => bug!("associated macro"),
             },
-            PathSource::Expr(parent) => match parent.map(|p| &p.kind) {
+            PathSource::Expr(parent) => match &parent.as_ref().map(|p| &p.kind) {
                 // "function" here means "anything callable" rather than `DefKind::Fn`,
                 // this is not precise but usually more helpful than just "value".
-                Some(&ExprKind::Call(..)) => "function",
+                Some(ExprKind::Call(call_expr, _)) => {
+                    match &call_expr.kind {
+                        ExprKind::Path(_, path) => {
+                            let mut msg = "function";
+                            if let Some(segment) = path.segments.iter().last() {
+                                if let Some(c) = segment.ident.to_string().chars().next() {
+                                    if c.is_uppercase() {
+                                        msg = "function, tuple struct or tuple variant";
+                                    }
+                                }
+                            }
+                            msg
+                        }
+                        _ => "function"
+                    }
+                }
                 _ => "value",
             },
         }

src/librustc_resolve/late/diagnostics.rs

@@ -1,7 +1,7 @@
 use crate::{CrateLint, Module, ModuleKind, ModuleOrUniformRoot};
 use crate::{PathResult, PathSource, Segment};
 use crate::path_names_to_string;
-use crate::diagnostics::{add_typo_suggestion, ImportSuggestion, TypoSuggestion};
+use crate::diagnostics::{ImportSuggestion, TypoSuggestion};
 use crate::late::{LateResolutionVisitor, RibKind};
 
 use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
@@ -237,18 +237,19 @@ impl<'a> LateResolutionVisitor<'a, '_> {
         }
 
         // Try Levenshtein algorithm.
-        let levenshtein_worked = add_typo_suggestion(
-            &mut err, self.lookup_typo_candidate(path, ns, is_expected, span), ident_span
-        );
+        let typo_sugg = self.lookup_typo_candidate(path, ns, is_expected, span);
+        let levenshtein_worked = self.r.add_typo_suggestion(&mut err, typo_sugg, ident_span);
 
         // Try context-dependent help if relaxed lookup didn't work.
         if let Some(res) = res {
-            if self.smart_resolve_context_dependent_help(&mut err,
-                                                         span,
-                                                         source,
-                                                         res,
-                                                         &path_str,
-                                                         &fallback_label) {
+            if self.smart_resolve_context_dependent_help(
+                &mut err,
+                span,
+                source,
+                res,
+                &path_str,
+                &fallback_label,
+            ) {
                 return (err, candidates);
             }
         }

src/librustc_typeck/check/mod.rs

@@ -2269,7 +2269,7 @@ pub fn check_enum<'tcx>(tcx: TyCtxt<'tcx>, sp: Span, vs: &'tcx [hir::Variant], i
 
 fn report_unexpected_variant_res(tcx: TyCtxt<'_>, res: Res, span: Span, qpath: &QPath) {
     span_err!(tcx.sess, span, E0533,
-              "expected unit struct/variant or constant, found {} `{}`",
+              "expected unit struct, unit variant or constant, found {} `{}`",
               res.descr(),
               hir::print::to_string(tcx.hir(), |s| s.print_qpath(qpath, false)));
 }

src/librustc_typeck/check/pat.rs

@@ -613,9 +613,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             }
         };
         let report_unexpected_res = |res: Res| {
-            let msg = format!("expected tuple struct/variant, found {} `{}`",
-                              res.descr(),
-                              hir::print::to_string(tcx.hir(), |s| s.print_qpath(qpath, false)));
+            let msg = format!(
+                "expected tuple struct or tuple variant, found {} `{}`",
+                res.descr(),
+                hir::print::to_string(tcx.hir(), |s| s.print_qpath(qpath, false)),
+            );
             let mut err = struct_span_err!(tcx.sess, pat.span, E0164, "{}", msg);
             match (res, &pat.kind) {
                 (Res::Def(DefKind::Fn, _), _) | (Res::Def(DefKind::Method, _), _) => {

src/librustc_typeck/error_codes.rs

@@ -4346,11 +4346,12 @@ enum X {
     Entry,
 }
 
-X::Entry(); // error: expected function, found `X::Entry`
+X::Entry(); // error: expected function, tuple struct or tuple variant,
+            // found `X::Entry`
 
 // Or even simpler:
 let x = 0i32;
-x(); // error: expected function, found `i32`
+x(); // error: expected function, tuple struct or tuple variant, found `i32`
 ```
 
 Only functions and methods can be called using `()`. Example:

src/test/ui/associated-types/associated-types-eq-1.stderr

@@ -1,6 +1,8 @@
 error[E0412]: cannot find type `A` in this scope
   --> $DIR/associated-types-eq-1.rs:10:12
    |
+LL | fn foo2<I: Foo>(x: I) {
+   |         - similarly named type parameter `I` defined here
 LL |     let _: A = x.boo();
    |            ^ help: a type parameter with a similar name exists: `I`
 

src/test/ui/class-missing-self.rs

@@ -7,7 +7,7 @@ impl Cat {
     fn meow(&self) {
       println!("Meow");
       meows += 1; //~ ERROR cannot find value `meows` in this scope
-      sleep();     //~ ERROR cannot find function `sleep` in this scope
+      sleep();     //~ ERROR cannot find function `sleep` in this
     }
 
 }

src/test/ui/const-generics/struct-with-invalid-const-param.stderr

@@ -2,7 +2,10 @@ error[E0573]: expected type, found const parameter `C`
   --> $DIR/struct-with-invalid-const-param.rs:4:23
    |
 LL | struct S<const C: u8>(C);
-   |                       ^ help: a struct with a similar name exists: `S`
+   | ----------------------^--
+   | |                     |
+   | |                     help: a struct with a similar name exists: `S`
+   | similarly named struct `S` defined here
 
 warning: the feature `const_generics` is incomplete and may cause the compiler to crash
   --> $DIR/struct-with-invalid-const-param.rs:1:12

src/test/ui/did_you_mean/issue-43871-enum-instead-of-variant.rs

@@ -16,21 +16,21 @@ enum ManyVariants {
 }
 
 fn result_test() {
-    let x = Option(1); //~ ERROR expected function, found enum
+    let x = Option(1); //~ ERROR expected function, tuple struct or tuple variant, found enum
 
-    if let Option(_) = x { //~ ERROR expected tuple struct/variant, found enum
+    if let Option(_) = x { //~ ERROR expected tuple struct or tuple variant, found enum
         println!("It is OK.");
     }
 
     let y = Example::Ex(String::from("test"));
 
-    if let Example(_) = y { //~ ERROR expected tuple struct/variant, found enum
+    if let Example(_) = y { //~ ERROR expected tuple struct or tuple variant, found enum
         println!("It is OK.");
     }
 
-    let y = Void(); //~ ERROR expected function, found enum
+    let y = Void(); //~ ERROR expected function, tuple struct or tuple variant, found enum
 
-    let z = ManyVariants(); //~ ERROR expected function, found enum
+    let z = ManyVariants(); //~ ERROR expected function, tuple struct or tuple variant, found enum
 }
 
 fn main() {}

src/test/ui/did_you_mean/issue-43871-enum-instead-of-variant.stderr

@@ -1,4 +1,4 @@
-error[E0423]: expected function, found enum `Option`
+error[E0423]: expected function, tuple struct or tuple variant, found enum `Option`
   --> $DIR/issue-43871-enum-instead-of-variant.rs:19:13
    |
 LL |     let x = Option(1);
@@ -11,7 +11,7 @@ LL |     let x = std::option::Option::None(1);
 LL |     let x = std::option::Option::Some(1);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0532]: expected tuple struct/variant, found enum `Option`
+error[E0532]: expected tuple struct or tuple variant, found enum `Option`
   --> $DIR/issue-43871-enum-instead-of-variant.rs:21:12
    |
 LL |     if let Option(_) = x {
@@ -24,7 +24,7 @@ LL |     if let std::option::Option::None(_) = x {
 LL |     if let std::option::Option::Some(_) = x {
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0532]: expected tuple struct/variant, found enum `Example`
+error[E0532]: expected tuple struct or tuple variant, found enum `Example`
   --> $DIR/issue-43871-enum-instead-of-variant.rs:27:12
    |
 LL |     if let Example(_) = y {
@@ -37,13 +37,13 @@ LL |     if let Example::Ex(_) = y {
 LL |     if let Example::NotEx(_) = y {
    |            ^^^^^^^^^^^^^^
 
-error[E0423]: expected function, found enum `Void`
+error[E0423]: expected function, tuple struct or tuple variant, found enum `Void`
   --> $DIR/issue-43871-enum-instead-of-variant.rs:31:13
    |
 LL |     let y = Void();
    |             ^^^^
 
-error[E0423]: expected function, found enum `ManyVariants`
+error[E0423]: expected function, tuple struct or tuple variant, found enum `ManyVariants`
   --> $DIR/issue-43871-enum-instead-of-variant.rs:33:13
    |
 LL |     let z = ManyVariants();

src/test/ui/empty/empty-struct-braces-expr.rs

@@ -13,12 +13,15 @@ enum E {
 
 fn main() {
     let e1 = Empty1; //~ ERROR expected value, found struct `Empty1`
-    let e1 = Empty1(); //~ ERROR expected function, found struct `Empty1`
+    let e1 = Empty1();
+    //~^ ERROR expected function, tuple struct or tuple variant, found struct `Empty1`
     let e3 = E::Empty3; //~ ERROR expected value, found struct variant `E::Empty3`
-    let e3 = E::Empty3(); //~ ERROR expected function, found struct variant `E::Empty3`
+    let e3 = E::Empty3();
+    //~^ ERROR expected function, tuple struct or tuple variant, found struct variant `E::Empty3`
 
     let xe1 = XEmpty1; //~ ERROR expected value, found struct `XEmpty1`
-    let xe1 = XEmpty1(); //~ ERROR expected function, found struct `XEmpty1`
+    let xe1 = XEmpty1();
+    //~^ ERROR expected function, tuple struct or tuple variant, found struct `XEmpty1`
     let xe3 = XE::Empty3; //~ ERROR no variant or associated item named `Empty3` found for type
     let xe3 = XE::Empty3(); //~ ERROR no variant or associated item named `Empty3` found for type