Fix #2494 add suggestion for unreadable_literal

Cover large digit group case in tests
Cover inconsistent group case in tests

Author: alexheretic

clippy_lints/src/literal_representation.rs

@@ -4,7 +4,7 @@
 use rustc::lint::*;
 use syntax::ast::*;
 use syntax_pos;
-use utils::{in_external_macro, snippet_opt, span_help_and_lint};
+use utils::{in_external_macro, snippet_opt, span_lint_and_sugg};
 
 /// **What it does:** Warns if a long integral or floating-point constant does
 /// not contain underscores.
@@ -222,33 +222,37 @@ enum WarningType {
 impl WarningType {
     pub fn display(&self, grouping_hint: &str, cx: &EarlyContext, span: &syntax_pos::Span) {
         match *self {
-            WarningType::UnreadableLiteral => span_help_and_lint(
+            WarningType::UnreadableLiteral => span_lint_and_sugg(
                 cx,
                 UNREADABLE_LITERAL,
                 *span,
                 "long literal lacking separators",
-                &format!("consider: {}", grouping_hint),
+                "consider",
+                grouping_hint.to_owned(),
             ),
-            WarningType::LargeDigitGroups => span_help_and_lint(
+            WarningType::LargeDigitGroups => span_lint_and_sugg(
                 cx,
                 LARGE_DIGIT_GROUPS,
                 *span,
                 "digit groups should be smaller",
-                &format!("consider: {}", grouping_hint),
+                "consider",
+                grouping_hint.to_owned(),
             ),
-            WarningType::InconsistentDigitGrouping => span_help_and_lint(
+            WarningType::InconsistentDigitGrouping => span_lint_and_sugg(
                 cx,
                 INCONSISTENT_DIGIT_GROUPING,
                 *span,
                 "digits grouped inconsistently by underscores",
-                &format!("consider: {}", grouping_hint),
+                "consider",
+                grouping_hint.to_owned(),
             ),
-            WarningType::DecimalRepresentation => span_help_and_lint(
+            WarningType::DecimalRepresentation => span_lint_and_sugg(
                 cx,
                 DECIMAL_LITERAL_REPRESENTATION,
                 *span,
                 "integer literal has a better hexadecimal representation",
-                &format!("consider: {}", grouping_hint),
+                "consider",
+                grouping_hint.to_owned(),
             ),
         };
     }

tests/ui/unreadable_literal.rs

@@ -5,4 +5,7 @@
 fn main() {
     let good = (0b1011_i64, 0o1_234_u32, 0x1_234_567, 1_2345_6789, 1234_f32, 1_234.12_f32, 1_234.123_f32, 1.123_4_f32);
     let bad = (0b10110_i64, 0x12345678901_usize, 12345_f32, 1.23456_f32);
+
+    let large_digit_groups: u64 = 6186491_8973511;
+    let inconsistent_groups: u64 = 618_64_9189_73_511;
 }

tests/ui/unreadable_literal.stderr

@@ -2,34 +2,43 @@ error: long literal lacking separators
  --> $DIR/unreadable_literal.rs:7:16
   |
 7 |     let bad = (0b10110_i64, 0x12345678901_usize, 12345_f32, 1.23456_f32);
-  |                ^^^^^^^^^^^
+  |                ^^^^^^^^^^^ help: consider: `0b1_0110_i64`
   |
   = note: `-D unreadable-literal` implied by `-D warnings`
-  = help: consider: 0b1_0110_i64
 
 error: long literal lacking separators
  --> $DIR/unreadable_literal.rs:7:29
   |
 7 |     let bad = (0b10110_i64, 0x12345678901_usize, 12345_f32, 1.23456_f32);
-  |                             ^^^^^^^^^^^^^^^^^^^
-  |
-  = help: consider: 0x123_4567_8901_usize
+  |                             ^^^^^^^^^^^^^^^^^^^ help: consider: `0x123_4567_8901_usize`
 
 error: long literal lacking separators
  --> $DIR/unreadable_literal.rs:7:50
   |
 7 |     let bad = (0b10110_i64, 0x12345678901_usize, 12345_f32, 1.23456_f32);
-  |                                                  ^^^^^^^^^
-  |
-  = help: consider: 12_345_f32
+  |                                                  ^^^^^^^^^ help: consider: `12_345_f32`
 
 error: long literal lacking separators
  --> $DIR/unreadable_literal.rs:7:61
   |
 7 |     let bad = (0b10110_i64, 0x12345678901_usize, 12345_f32, 1.23456_f32);
-  |                                                             ^^^^^^^^^^^
+  |                                                             ^^^^^^^^^^^ help: consider: `1.234_56_f32`
+
+error: digit groups should be smaller
+ --> $DIR/unreadable_literal.rs:9:35
   |
-  = help: consider: 1.234_56_f32
+9 |     let large_digit_groups: u64 = 6186491_8973511;
+  |                                   ^^^^^^^^^^^^^^^ help: consider: `61_864_918_973_511`
+  |
+  = note: `-D large-digit-groups` implied by `-D warnings`
+
+error: digits grouped inconsistently by underscores
+  --> $DIR/unreadable_literal.rs:10:36
+   |
+10 |     let inconsistent_groups: u64 = 618_64_9189_73_511;
+   |                                    ^^^^^^^^^^^^^^^^^^ help: consider: `61_864_918_973_511`
+   |
+   = note: `-D inconsistent-digit-grouping` implied by `-D warnings`
 
-error: aborting due to 4 previous errors
+error: aborting due to 6 previous errors