Show wider and more accurate suggestion for const_static_lifetime

fixes #2365

Author: Manishearth

clippy_lints/src/const_static_lifetime.rs

@@ -1,6 +1,6 @@
 use syntax::ast::{Item, ItemKind, Ty, TyKind};
 use rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass};
-use utils::{in_macro, span_lint_and_then};
+use utils::{in_macro, snippet, span_lint_and_then};
 
 /// **What it does:** Checks for constants with an explicit `'static` lifetime.
 ///
@@ -51,14 +51,15 @@ impl StaticConst {
                         TyKind::Path(..) | TyKind::Slice(..) | TyKind::Array(..) |
                         TyKind::Tup(..) => {
                             if lifetime.ident.name == "'static" {
-                                let mut sug: String = String::new();
+                                let snip = snippet(cx, borrow_type.ty.span, "<type>");
+                                let sugg = format!("&{}", snip);
                                 span_lint_and_then(
                                     cx,
                                     CONST_STATIC_LIFETIME,
                                     lifetime.span,
                                     "Constants have by default a `'static` lifetime",
                                     |db| {
-                                        db.span_suggestion(lifetime.span, "consider removing `'static`", sug);
+                                        db.span_suggestion(ty.span, "consider removing `'static`", sugg);
                                     },
                                 );
                             }

tests/ui/const_static_lifetime.stderr

@@ -2,79 +2,79 @@ error: Constants have by default a `'static` lifetime
  --> $DIR/const_static_lifetime.rs:4:17
   |
 4 | const VAR_ONE: &'static str = "Test constant #1"; // ERROR Consider removing 'static.
-  |                 ^^^^^^^ help: consider removing `'static`
+  |                -^^^^^^^---- help: consider removing `'static`: `&str`
   |
   = note: `-D const-static-lifetime` implied by `-D warnings`
 
 error: Constants have by default a `'static` lifetime
  --> $DIR/const_static_lifetime.rs:8:21
   |
 8 | const VAR_THREE: &[&'static str] = &["one", "two"]; // ERROR Consider removing 'static
-  |                     ^^^^^^^ help: consider removing `'static`
+  |                    -^^^^^^^---- help: consider removing `'static`: `&str`
 
 error: Constants have by default a `'static` lifetime
   --> $DIR/const_static_lifetime.rs:10:32
    |
 10 | const VAR_FOUR: (&str, (&str, &'static str), &'static str) = ("on", ("th", "th"), "on"); // ERROR Consider removing 'static
-   |                                ^^^^^^^ help: consider removing `'static`
+   |                               -^^^^^^^---- help: consider removing `'static`: `&str`
 
 error: Constants have by default a `'static` lifetime
   --> $DIR/const_static_lifetime.rs:10:47
    |
 10 | const VAR_FOUR: (&str, (&str, &'static str), &'static str) = ("on", ("th", "th"), "on"); // ERROR Consider removing 'static
-   |                                               ^^^^^^^ help: consider removing `'static`
+   |                                              -^^^^^^^---- help: consider removing `'static`: `&str`
 
 error: Constants have by default a `'static` lifetime
   --> $DIR/const_static_lifetime.rs:12:18
    |
 12 | const VAR_FIVE: &'static [&[&'static str]] = &[&["test"], &["other one"]]; // ERROR Consider removing 'static
-   |                  ^^^^^^^ help: consider removing `'static`
+   |                 -^^^^^^^------------------ help: consider removing `'static`: `&[&[&'static str]]`
 
 error: Constants have by default a `'static` lifetime
   --> $DIR/const_static_lifetime.rs:12:30
    |
 12 | const VAR_FIVE: &'static [&[&'static str]] = &[&["test"], &["other one"]]; // ERROR Consider removing 'static
-   |                              ^^^^^^^ help: consider removing `'static`
+   |                             -^^^^^^^---- help: consider removing `'static`: `&str`
 
 error: Constants have by default a `'static` lifetime
   --> $DIR/const_static_lifetime.rs:14:17
    |
 14 | const VAR_SIX: &'static u8 = &5;
-   |                 ^^^^^^^ help: consider removing `'static`
+   |                -^^^^^^^--- help: consider removing `'static`: `&u8`
 
 error: Constants have by default a `'static` lifetime
   --> $DIR/const_static_lifetime.rs:16:29
    |
 16 | const VAR_SEVEN: &[&(&str, &'static [&'static str])] = &[&("one", &["other one"])];
-   |                             ^^^^^^^ help: consider removing `'static`
+   |                            -^^^^^^^--------------- help: consider removing `'static`: `&[&'static str]`
 
 error: Constants have by default a `'static` lifetime
   --> $DIR/const_static_lifetime.rs:16:39
    |
 16 | const VAR_SEVEN: &[&(&str, &'static [&'static str])] = &[&("one", &["other one"])];
-   |                                       ^^^^^^^ help: consider removing `'static`
+   |                                      -^^^^^^^---- help: consider removing `'static`: `&str`
 
 error: Constants have by default a `'static` lifetime
   --> $DIR/const_static_lifetime.rs:18:20
    |
 18 | const VAR_HEIGHT: &'static Foo = &Foo {};
-   |                    ^^^^^^^ help: consider removing `'static`
+   |                   -^^^^^^^---- help: consider removing `'static`: `&Foo`
 
 error: Constants have by default a `'static` lifetime
   --> $DIR/const_static_lifetime.rs:20:19
    |
 20 | const VAR_SLICE: &'static [u8] = b"Test constant #1"; // ERROR Consider removing 'static.
-   |                   ^^^^^^^ help: consider removing `'static`
+   |                  -^^^^^^^----- help: consider removing `'static`: `&[u8]`
 
 error: Constants have by default a `'static` lifetime
   --> $DIR/const_static_lifetime.rs:22:19
    |
 22 | const VAR_TUPLE: &'static (u8, u8) = &(1, 2); // ERROR Consider removing 'static.
-   |                   ^^^^^^^ help: consider removing `'static`
+   |                  -^^^^^^^--------- help: consider removing `'static`: `&(u8, u8)`
 
 error: Constants have by default a `'static` lifetime
   --> $DIR/const_static_lifetime.rs:24:19
    |
 24 | const VAR_ARRAY: &'static [u8; 1] = b"T"; // ERROR Consider removing 'static.
-   |                   ^^^^^^^ help: consider removing `'static`
+   |                  -^^^^^^^-------- help: consider removing `'static`: `&[u8; 1]`