From eea30777ddef56383199ff70fd14b28335afc1e5 Mon Sep 17 00:00:00 2001
From: sinkuu <sinkuu@sinkuu.xyz>
Date: Tue, 17 Oct 2017 21:39:24 +0900
Subject: [PATCH] Type parameter change and type change are now in a multispan
 suggestion

---
 clippy_lints/src/types.rs       | 47 ++++++++++++++------------
 tests/ui/implicit_hasher.stderr | 60 ++++++---------------------------
 2 files changed, 35 insertions(+), 72 deletions(-)

diff --git a/clippy_lints/src/types.rs b/clippy_lints/src/types.rs
index 082dce43e097..a284392bfa0b 100644
--- a/clippy_lints/src/types.rs
+++ b/clippy_lints/src/types.rs
@@ -1453,8 +1453,8 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for InvalidUpcastComparisons {
     }
 }
 
-/// **What it does:** Checks for public `impl` or `fn` missing generalization over
-/// different hashers and implicitly defaulting to the default hashing
+/// **What it does:** Checks for public `impl` or `fn` missing generalization
+/// over different hashers and implicitly defaulting to the default hashing
 /// algorithm (SipHash).
 ///
 /// **Why is this bad?** `HashMap` or `HashSet` with custom hashers cannot be
@@ -1505,26 +1505,29 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ImplicitHasher {
                 &generics_snip[1..generics_snip.len() - 1]
             };
 
-            db.span_suggestion(
-                generics_suggestion_span,
-                "consider adding a type parameter",
-                format!(
-                    "<{}{}S: ::std::hash::BuildHasher{}>",
-                    generics_snip,
-                    if generics_snip.is_empty() { "" } else { ", " },
-                    if vis.suggestions.is_empty() {
-                        ""
-                    } else {
-                        // request users to add `Default` bound so that generic constructors can be used
-                        " + Default"
-                    },
-                ),
-            );
-
-            db.span_suggestion(
-                target.span(),
-                "...and change the type to",
-                format!("{}<{}, S>", target.type_name(), target.type_arguments(),),
+            multispan_sugg(
+                db,
+                "consider adding a type parameter".to_string(),
+                vec![
+                    (
+                        generics_suggestion_span,
+                        format!(
+                            "<{}{}S: ::std::hash::BuildHasher{}>",
+                            generics_snip,
+                            if generics_snip.is_empty() { "" } else { ", " },
+                            if vis.suggestions.is_empty() {
+                                ""
+                            } else {
+                                // request users to add `Default` bound so that generic constructors can be used
+                                " + Default"
+                            },
+                        ),
+                    ),
+                    (
+                        target.span(),
+                        format!("{}<{}, S>", target.type_name(), target.type_arguments(),),
+                    ),
+                ],
             );
 
             if !vis.suggestions.is_empty() {
diff --git a/tests/ui/implicit_hasher.stderr b/tests/ui/implicit_hasher.stderr
index be799f49d005..cc0bdc327b4a 100644
--- a/tests/ui/implicit_hasher.stderr
+++ b/tests/ui/implicit_hasher.stderr
@@ -7,12 +7,8 @@ error: impl for `HashMap` should be generarized over different hashers
    = note: `-D implicit-hasher` implied by `-D warnings`
 help: consider adding a type parameter
    |
-11 | impl<K: Hash + Eq, V, S: ::std::hash::BuildHasher + Default> Foo<i8> for HashMap<K, V> {
+11 | impl<K: Hash + Eq, V, S: ::std::hash::BuildHasher + Default> Foo<i8> for HashMap<K, V, S> {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-help: ...and change the type to
-   |
-11 | impl<K: Hash + Eq, V> Foo<i8> for HashMap<K, V, S> {
-   |                                   ^^^^^^^^^^^^^^^^
 help: ...and use generic constructor
    |
 17 |         (HashMap::default(), HashMap::with_capacity_and_hasher(10, Default::default()))
@@ -26,12 +22,8 @@ error: impl for `HashMap` should be generarized over different hashers
    |
 help: consider adding a type parameter
    |
-20 | impl<K: Hash + Eq, V, S: ::std::hash::BuildHasher + Default> Foo<i8> for (HashMap<K, V>,) {
+20 | impl<K: Hash + Eq, V, S: ::std::hash::BuildHasher + Default> Foo<i8> for (HashMap<K, V, S>,) {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-help: ...and change the type to
-   |
-20 | impl<K: Hash + Eq, V> Foo<i8> for (HashMap<K, V, S>,) {
-   |                                    ^^^^^^^^^^^^^^^^
 help: ...and use generic constructor
    |
 22 |         ((HashMap::default(),), (HashMap::with_capacity_and_hasher(10, Default::default()),))
@@ -45,12 +37,8 @@ error: impl for `HashMap` should be generarized over different hashers
    |
 help: consider adding a type parameter
    |
-25 | impl<S: ::std::hash::BuildHasher + Default> Foo<i16> for HashMap<String, String> {
+25 | impl<S: ::std::hash::BuildHasher + Default> Foo<i16> for HashMap<String, String, S> {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-help: ...and change the type to
-   |
-25 | impl Foo<i16> for HashMap<String, String, S> {
-   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^
 help: ...and use generic constructor
    |
 27 |         (HashMap::default(), HashMap::with_capacity_and_hasher(10, Default::default()))
@@ -64,12 +52,8 @@ error: impl for `HashSet` should be generarized over different hashers
    |
 help: consider adding a type parameter
    |
-43 | impl<T: Hash + Eq, S: ::std::hash::BuildHasher + Default> Foo<i8> for HashSet<T> {
+43 | impl<T: Hash + Eq, S: ::std::hash::BuildHasher + Default> Foo<i8> for HashSet<T, S> {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-help: ...and change the type to
-   |
-43 | impl<T: Hash + Eq> Foo<i8> for HashSet<T, S> {
-   |                                ^^^^^^^^^^^^^
 help: ...and use generic constructor
    |
 45 |         (HashSet::default(), HashSet::with_capacity_and_hasher(10, Default::default()))
@@ -83,12 +67,8 @@ error: impl for `HashSet` should be generarized over different hashers
    |
 help: consider adding a type parameter
    |
-48 | impl<S: ::std::hash::BuildHasher + Default> Foo<i16> for HashSet<String> {
+48 | impl<S: ::std::hash::BuildHasher + Default> Foo<i16> for HashSet<String, S> {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-help: ...and change the type to
-   |
-48 | impl Foo<i16> for HashSet<String, S> {
-   |                   ^^^^^^^^^^^^^^^^^^
 help: ...and use generic constructor
    |
 50 |         (HashSet::default(), HashSet::with_capacity_and_hasher(10, Default::default()))
@@ -102,12 +82,8 @@ error: parameter of type `HashMap` should be generarized over different hashers
    |
 help: consider adding a type parameter
    |
-65 | pub fn foo<S: ::std::hash::BuildHasher>(_map: &mut HashMap<i32, i32>, _set: &mut HashSet<i32>) {
+65 | pub fn foo<S: ::std::hash::BuildHasher>(_map: &mut HashMap<i32, i32, S>, _set: &mut HashSet<i32>) {
    |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-help: ...and change the type to
-   |
-65 | pub fn foo(_map: &mut HashMap<i32, i32, S>, _set: &mut HashSet<i32>) {
-   |                       ^^^^^^^^^^^^^^^^^^^^
 
 error: parameter of type `HashSet` should be generarized over different hashers
   --> $DIR/implicit_hasher.rs:65:53
@@ -117,12 +93,8 @@ error: parameter of type `HashSet` should be generarized over different hashers
    |
 help: consider adding a type parameter
    |
-65 | pub fn foo<S: ::std::hash::BuildHasher>(_map: &mut HashMap<i32, i32>, _set: &mut HashSet<i32>) {
+65 | pub fn foo<S: ::std::hash::BuildHasher>(_map: &mut HashMap<i32, i32>, _set: &mut HashSet<i32, S>) {
    |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-help: ...and change the type to
-   |
-65 | pub fn foo(_map: &mut HashMap<i32, i32>, _set: &mut HashSet<i32, S>) {
-   |                                                     ^^^^^^^^^^^^^^^
 
 error: impl for `HashMap` should be generarized over different hashers
   --> $DIR/implicit_hasher.rs:70:43
@@ -135,12 +107,8 @@ error: impl for `HashMap` should be generarized over different hashers
    |
 help: consider adding a type parameter
    |
-70 |         impl<K: Hash + Eq, V, S: ::std::hash::BuildHasher + Default> Foo<u8> for HashMap<K, V> {
+70 |         impl<K: Hash + Eq, V, S: ::std::hash::BuildHasher + Default> Foo<u8> for HashMap<K, V, S> {
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-help: ...and change the type to
-   |
-70 |         impl<K: Hash + Eq, V> Foo<u8> for HashMap<K, V, S> {
-   |                                           ^^^^^^^^^^^^^^^^
 help: ...and use generic constructor
    |
 72 |                 (HashMap::default(), HashMap::with_capacity_and_hasher(10, Default::default()))
@@ -157,12 +125,8 @@ error: parameter of type `HashMap` should be generarized over different hashers
    |
 help: consider adding a type parameter
    |
-78 |         pub fn $name<S: ::std::hash::BuildHasher>(_map: &mut HashMap<i32, i32>, _set: &mut HashSet<i32>) {
+78 |         pub fn $name<S: ::std::hash::BuildHasher>(_map: &mut HashMap<i32, i32, S>, _set: &mut HashSet<i32>) {
    |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-help: ...and change the type to
-   |
-78 |         pub fn $name(_map: &mut HashMap<i32, i32, S>, _set: &mut HashSet<i32>) {
-   |                                 ^^^^^^^^^^^^^^^^^^^^
 
 error: parameter of type `HashSet` should be generarized over different hashers
   --> $DIR/implicit_hasher.rs:78:63
@@ -175,10 +139,6 @@ error: parameter of type `HashSet` should be generarized over different hashers
    |
 help: consider adding a type parameter
    |
-78 |         pub fn $name<S: ::std::hash::BuildHasher>(_map: &mut HashMap<i32, i32>, _set: &mut HashSet<i32>) {
+78 |         pub fn $name<S: ::std::hash::BuildHasher>(_map: &mut HashMap<i32, i32>, _set: &mut HashSet<i32, S>) {
    |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-help: ...and change the type to
-   |
-78 |         pub fn $name(_map: &mut HashMap<i32, i32>, _set: &mut HashSet<i32, S>) {
-   |                                                               ^^^^^^^^^^^^^^^