Add note about rem_euclid function for integral types

mgr-inz-rafal · mgr-inz-rafal · commit 4e66671ef8fd · 2019-12-18T23:14:38.000+01:00
diff --git a/clippy_lints/src/modulo_arithmetic.rs b/clippy_lints/src/modulo_arithmetic.rs
@@ -96,10 +96,15 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ModuloArithmetic {
                                     MODULO_ARITHMETIC,
                                     expr.span,
                                     &format!(
-                                        "you are using modulo operator on constants with different signs: `{} % {}`", lhs_operand.string_representation.unwrap(), rhs_operand.string_representation.unwrap()
+                                        "you are using modulo operator on constants with different signs: `{} % {}`",
+                                            lhs_operand.string_representation.unwrap(),
+                                            rhs_operand.string_representation.unwrap()
                                     ),
                                     expr.span,
-                                    "double check for expected result especially when interoperating with different languages",
+                                    &format!(
+                                        "double check for expected result especially when interoperating with different languages{}",
+                                            if lhs_operand.is_integral {" or consider using `rem_euclid` or similar function"} else {""}
+                                    ),
                                 );
                             }
                         }
@@ -113,7 +118,10 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ModuloArithmetic {
                                     expr.span,
                                     "you are using modulo operator on types that might have different signs",
                                     expr.span,
-                                    "double check for expected result especially when interoperating with different languages",
+                                    &format!(
+                                        "double check for expected result especially when interoperating with different languages{}",
+                                            if lhs_type.is_integral() {" or consider using `rem_euclid` or similar function"} else {""}
+                                    ),
                                 );
                             }
                             }
diff --git a/tests/ui/modulo_arithmetic.stderr b/tests/ui/modulo_arithmetic.stderr
@@ -5,15 +5,15 @@ LL |     -1 % 2;
    |     ^^^^^^
    |
    = note: `-D clippy::modulo-arithmetic` implied by `-D warnings`
-   = note: double check for expected result especially when interoperating with different languages
+   = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
 
 error: you are using modulo operator on constants with different signs: `1 % -2`
   --> $DIR/modulo_arithmetic.rs:14:5
    |
 LL |     1 % -2;
    |     ^^^^^^
    |
-   = note: double check for expected result especially when interoperating with different languages
+   = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
 
 error: you are using modulo operator on constants with different signs: `-1.600 % 2.100`
   --> $DIR/modulo_arithmetic.rs:15:5
@@ -37,15 +37,15 @@ error: you are using modulo operator on constants with different signs: `-1 % 3`
 LL |     (1 - 2) % (1 + 2);
    |     ^^^^^^^^^^^^^^^^^
    |
-   = note: double check for expected result especially when interoperating with different languages
+   = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
 
 error: you are using modulo operator on constants with different signs: `3 % -1`
   --> $DIR/modulo_arithmetic.rs:18:5
    |
 LL |     (1 + 2) % (1 - 2);
    |     ^^^^^^^^^^^^^^^^^
    |
-   = note: double check for expected result especially when interoperating with different languages
+   = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
 
 error: you are using modulo operator on constants with different signs: `-1.200 % 3.400`
   --> $DIR/modulo_arithmetic.rs:19:5
@@ -69,127 +69,127 @@ error: you are using modulo operator on constants with different signs: `-35 % 3
 LL |     35 * (7 - 4 * 2) % (-500 * -600);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: double check for expected result especially when interoperating with different languages
+   = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
 
 error: you are using modulo operator on constants with different signs: `-1 % 2`
   --> $DIR/modulo_arithmetic.rs:23:5
    |
 LL |     -1i8 % 2i8;
    |     ^^^^^^^^^^
    |
-   = note: double check for expected result especially when interoperating with different languages
+   = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
 
 error: you are using modulo operator on constants with different signs: `1 % -2`
   --> $DIR/modulo_arithmetic.rs:24:5
    |
 LL |     1i8 % -2i8;
    |     ^^^^^^^^^^
    |
-   = note: double check for expected result especially when interoperating with different languages
+   = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
 
 error: you are using modulo operator on constants with different signs: `-1 % 2`
   --> $DIR/modulo_arithmetic.rs:25:5
    |
 LL |     -1i16 % 2i16;
    |     ^^^^^^^^^^^^
    |
-   = note: double check for expected result especially when interoperating with different languages
+   = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
 
 error: you are using modulo operator on constants with different signs: `1 % -2`
   --> $DIR/modulo_arithmetic.rs:26:5
    |
 LL |     1i16 % -2i16;
    |     ^^^^^^^^^^^^
    |
-   = note: double check for expected result especially when interoperating with different languages
+   = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
 
 error: you are using modulo operator on constants with different signs: `-1 % 2`
   --> $DIR/modulo_arithmetic.rs:27:5
    |
 LL |     -1i32 % 2i32;
    |     ^^^^^^^^^^^^
    |
-   = note: double check for expected result especially when interoperating with different languages
+   = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
 
 error: you are using modulo operator on constants with different signs: `1 % -2`
   --> $DIR/modulo_arithmetic.rs:28:5
    |
 LL |     1i32 % -2i32;
    |     ^^^^^^^^^^^^
    |
-   = note: double check for expected result especially when interoperating with different languages
+   = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
 
 error: you are using modulo operator on constants with different signs: `-1 % 2`
   --> $DIR/modulo_arithmetic.rs:29:5
    |
 LL |     -1i64 % 2i64;
    |     ^^^^^^^^^^^^
    |
-   = note: double check for expected result especially when interoperating with different languages
+   = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
 
 error: you are using modulo operator on constants with different signs: `1 % -2`
   --> $DIR/modulo_arithmetic.rs:30:5
    |
 LL |     1i64 % -2i64;
    |     ^^^^^^^^^^^^
    |
-   = note: double check for expected result especially when interoperating with different languages
+   = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
 
 error: you are using modulo operator on constants with different signs: `-1 % 2`
   --> $DIR/modulo_arithmetic.rs:31:5
    |
 LL |     -1i128 % 2i128;
    |     ^^^^^^^^^^^^^^
    |
-   = note: double check for expected result especially when interoperating with different languages
+   = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
 
 error: you are using modulo operator on constants with different signs: `1 % -2`
   --> $DIR/modulo_arithmetic.rs:32:5
    |
 LL |     1i128 % -2i128;
    |     ^^^^^^^^^^^^^^
    |
-   = note: double check for expected result especially when interoperating with different languages
+   = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
 
 error: you are using modulo operator on constants with different signs: `-1 % 2`
   --> $DIR/modulo_arithmetic.rs:33:5
    |
 LL |     -1isize % 2isize;
    |     ^^^^^^^^^^^^^^^^
    |
-   = note: double check for expected result especially when interoperating with different languages
+   = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
 
 error: you are using modulo operator on constants with different signs: `1 % -2`
   --> $DIR/modulo_arithmetic.rs:34:5
    |
 LL |     1isize % -2isize;
    |     ^^^^^^^^^^^^^^^^
    |
-   = note: double check for expected result especially when interoperating with different languages
+   = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
 
 error: you are using modulo operator on types that might have different signs
   --> $DIR/modulo_arithmetic.rs:39:5
    |
 LL |     a % b;
    |     ^^^^^
    |
-   = note: double check for expected result especially when interoperating with different languages
+   = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
 
 error: you are using modulo operator on types that might have different signs
   --> $DIR/modulo_arithmetic.rs:40:5
    |
 LL |     b % a;
    |     ^^^^^
    |
-   = note: double check for expected result especially when interoperating with different languages
+   = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
 
 error: you are using modulo operator on types that might have different signs
   --> $DIR/modulo_arithmetic.rs:41:5
    |
 LL |     b %= a;
    |     ^^^^^^
    |
-   = note: double check for expected result especially when interoperating with different languages
+   = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
 
 error: you are using modulo operator on types that might have different signs
   --> $DIR/modulo_arithmetic.rs:45:5
@@ -245,15 +245,15 @@ error: you are using modulo operator on types that might have different signs
 LL |     a % b;
    |     ^^^^^
    |
-   = note: double check for expected result especially when interoperating with different languages
+   = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
 
 error: you are using modulo operator on types that might have different signs
   --> $DIR/modulo_arithmetic.rs:58:5
    |
 LL |     b %= a;
    |     ^^^^^^
    |
-   = note: double check for expected result especially when interoperating with different languages
+   = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
 
 error: aborting due to 32 previous errors
 

Original file line number	Diff line number	Diff line change
`@@ -5,15 +5,15 @@ LL \| -1 % 2;`
`5`	`5`	`\| ^^^^^^`
`6`	`6`	`\|`
`7`	`7`	= note: `-D clippy::modulo-arithmetic` implied by `-D warnings`
`8`		`- = note: double check for expected result especially when interoperating with different languages`
	`8`	+ = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
`9`	`9`
`10`	`10`	error: you are using modulo operator on constants with different signs: `1 % -2`
`11`	`11`	`--> $DIR/modulo_arithmetic.rs:14:5`
`12`	`12`	`\|`
`13`	`13`	`LL \| 1 % -2;`
`14`	`14`	`\| ^^^^^^`
`15`	`15`	`\|`
`16`		`- = note: double check for expected result especially when interoperating with different languages`
	`16`	+ = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
`17`	`17`
`18`	`18`	error: you are using modulo operator on constants with different signs: `-1.600 % 2.100`
`19`	`19`	`--> $DIR/modulo_arithmetic.rs:15:5`
@@ -37,15 +37,15 @@ error: you are using modulo operator on constants with different signs: `-1 % 3`
`37`	`37`	`LL \| (1 - 2) % (1 + 2);`
`38`	`38`	`\| ^^^^^^^^^^^^^^^^^`
`39`	`39`	`\|`
`40`		`- = note: double check for expected result especially when interoperating with different languages`
	`40`	+ = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
`41`	`41`
`42`	`42`	error: you are using modulo operator on constants with different signs: `3 % -1`
`43`	`43`	`--> $DIR/modulo_arithmetic.rs:18:5`
`44`	`44`	`\|`
`45`	`45`	`LL \| (1 + 2) % (1 - 2);`
`46`	`46`	`\| ^^^^^^^^^^^^^^^^^`
`47`	`47`	`\|`
`48`		`- = note: double check for expected result especially when interoperating with different languages`
	`48`	+ = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
`49`	`49`
`50`	`50`	error: you are using modulo operator on constants with different signs: `-1.200 % 3.400`
`51`	`51`	`--> $DIR/modulo_arithmetic.rs:19:5`
@@ -69,127 +69,127 @@ error: you are using modulo operator on constants with different signs: `-35 % 3
`69`	`69`	`LL \| 35 * (7 - 4 * 2) % (-500 * -600);`
`70`	`70`	`\| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^`
`71`	`71`	`\|`
`72`		`- = note: double check for expected result especially when interoperating with different languages`
	`72`	+ = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
`73`	`73`
`74`	`74`	error: you are using modulo operator on constants with different signs: `-1 % 2`
`75`	`75`	`--> $DIR/modulo_arithmetic.rs:23:5`
`76`	`76`	`\|`
`77`	`77`	`LL \| -1i8 % 2i8;`
`78`	`78`	`\| ^^^^^^^^^^`
`79`	`79`	`\|`
`80`		`- = note: double check for expected result especially when interoperating with different languages`
	`80`	+ = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
`81`	`81`
`82`	`82`	error: you are using modulo operator on constants with different signs: `1 % -2`
`83`	`83`	`--> $DIR/modulo_arithmetic.rs:24:5`
`84`	`84`	`\|`
`85`	`85`	`LL \| 1i8 % -2i8;`
`86`	`86`	`\| ^^^^^^^^^^`
`87`	`87`	`\|`
`88`		`- = note: double check for expected result especially when interoperating with different languages`
	`88`	+ = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
`89`	`89`
`90`	`90`	error: you are using modulo operator on constants with different signs: `-1 % 2`
`91`	`91`	`--> $DIR/modulo_arithmetic.rs:25:5`
`92`	`92`	`\|`
`93`	`93`	`LL \| -1i16 % 2i16;`
`94`	`94`	`\| ^^^^^^^^^^^^`
`95`	`95`	`\|`
`96`		`- = note: double check for expected result especially when interoperating with different languages`
	`96`	+ = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
`97`	`97`
`98`	`98`	error: you are using modulo operator on constants with different signs: `1 % -2`
`99`	`99`	`--> $DIR/modulo_arithmetic.rs:26:5`
`100`	`100`	`\|`
`101`	`101`	`LL \| 1i16 % -2i16;`
`102`	`102`	`\| ^^^^^^^^^^^^`
`103`	`103`	`\|`
`104`		`- = note: double check for expected result especially when interoperating with different languages`
	`104`	+ = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
`105`	`105`
`106`	`106`	error: you are using modulo operator on constants with different signs: `-1 % 2`
`107`	`107`	`--> $DIR/modulo_arithmetic.rs:27:5`
`108`	`108`	`\|`
`109`	`109`	`LL \| -1i32 % 2i32;`
`110`	`110`	`\| ^^^^^^^^^^^^`
`111`	`111`	`\|`
`112`		`- = note: double check for expected result especially when interoperating with different languages`
	`112`	+ = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
`113`	`113`
`114`	`114`	error: you are using modulo operator on constants with different signs: `1 % -2`
`115`	`115`	`--> $DIR/modulo_arithmetic.rs:28:5`
`116`	`116`	`\|`
`117`	`117`	`LL \| 1i32 % -2i32;`
`118`	`118`	`\| ^^^^^^^^^^^^`
`119`	`119`	`\|`
`120`		`- = note: double check for expected result especially when interoperating with different languages`
	`120`	+ = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
`121`	`121`
`122`	`122`	error: you are using modulo operator on constants with different signs: `-1 % 2`
`123`	`123`	`--> $DIR/modulo_arithmetic.rs:29:5`
`124`	`124`	`\|`
`125`	`125`	`LL \| -1i64 % 2i64;`
`126`	`126`	`\| ^^^^^^^^^^^^`
`127`	`127`	`\|`
`128`		`- = note: double check for expected result especially when interoperating with different languages`
	`128`	+ = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
`129`	`129`
`130`	`130`	error: you are using modulo operator on constants with different signs: `1 % -2`
`131`	`131`	`--> $DIR/modulo_arithmetic.rs:30:5`
`132`	`132`	`\|`
`133`	`133`	`LL \| 1i64 % -2i64;`
`134`	`134`	`\| ^^^^^^^^^^^^`
`135`	`135`	`\|`
`136`		`- = note: double check for expected result especially when interoperating with different languages`
	`136`	+ = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
`137`	`137`
`138`	`138`	error: you are using modulo operator on constants with different signs: `-1 % 2`
`139`	`139`	`--> $DIR/modulo_arithmetic.rs:31:5`
`140`	`140`	`\|`
`141`	`141`	`LL \| -1i128 % 2i128;`
`142`	`142`	`\| ^^^^^^^^^^^^^^`
`143`	`143`	`\|`
`144`		`- = note: double check for expected result especially when interoperating with different languages`
	`144`	+ = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
`145`	`145`
`146`	`146`	error: you are using modulo operator on constants with different signs: `1 % -2`
`147`	`147`	`--> $DIR/modulo_arithmetic.rs:32:5`
`148`	`148`	`\|`
`149`	`149`	`LL \| 1i128 % -2i128;`
`150`	`150`	`\| ^^^^^^^^^^^^^^`
`151`	`151`	`\|`
`152`		`- = note: double check for expected result especially when interoperating with different languages`
	`152`	+ = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
`153`	`153`
`154`	`154`	error: you are using modulo operator on constants with different signs: `-1 % 2`
`155`	`155`	`--> $DIR/modulo_arithmetic.rs:33:5`
`156`	`156`	`\|`
`157`	`157`	`LL \| -1isize % 2isize;`
`158`	`158`	`\| ^^^^^^^^^^^^^^^^`
`159`	`159`	`\|`
`160`		`- = note: double check for expected result especially when interoperating with different languages`
	`160`	+ = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
`161`	`161`
`162`	`162`	error: you are using modulo operator on constants with different signs: `1 % -2`
`163`	`163`	`--> $DIR/modulo_arithmetic.rs:34:5`
`164`	`164`	`\|`
`165`	`165`	`LL \| 1isize % -2isize;`
`166`	`166`	`\| ^^^^^^^^^^^^^^^^`
`167`	`167`	`\|`
`168`		`- = note: double check for expected result especially when interoperating with different languages`
	`168`	+ = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
`169`	`169`
`170`	`170`	`error: you are using modulo operator on types that might have different signs`
`171`	`171`	`--> $DIR/modulo_arithmetic.rs:39:5`
`172`	`172`	`\|`
`173`	`173`	`LL \| a % b;`
`174`	`174`	`\| ^^^^^`
`175`	`175`	`\|`
`176`		`- = note: double check for expected result especially when interoperating with different languages`
	`176`	+ = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
`177`	`177`
`178`	`178`	`error: you are using modulo operator on types that might have different signs`
`179`	`179`	`--> $DIR/modulo_arithmetic.rs:40:5`
`180`	`180`	`\|`
`181`	`181`	`LL \| b % a;`
`182`	`182`	`\| ^^^^^`
`183`	`183`	`\|`
`184`		`- = note: double check for expected result especially when interoperating with different languages`
	`184`	+ = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
`185`	`185`
`186`	`186`	`error: you are using modulo operator on types that might have different signs`
`187`	`187`	`--> $DIR/modulo_arithmetic.rs:41:5`
`188`	`188`	`\|`
`189`	`189`	`LL \| b %= a;`
`190`	`190`	`\| ^^^^^^`
`191`	`191`	`\|`
`192`		`- = note: double check for expected result especially when interoperating with different languages`
	`192`	+ = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
`193`	`193`
`194`	`194`	`error: you are using modulo operator on types that might have different signs`
`195`	`195`	`--> $DIR/modulo_arithmetic.rs:45:5`
`@@ -245,15 +245,15 @@ error: you are using modulo operator on types that might have different signs`
`245`	`245`	`LL \| a % b;`
`246`	`246`	`\| ^^^^^`
`247`	`247`	`\|`
`248`		`- = note: double check for expected result especially when interoperating with different languages`
	`248`	+ = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
`249`	`249`
`250`	`250`	`error: you are using modulo operator on types that might have different signs`
`251`	`251`	`--> $DIR/modulo_arithmetic.rs:58:5`
`252`	`252`	`\|`
`253`	`253`	`LL \| b %= a;`
`254`	`254`	`\| ^^^^^^`
`255`	`255`	`\|`
`256`		`- = note: double check for expected result especially when interoperating with different languages`
	`256`	+ = note: double check for expected result especially when interoperating with different languages or consider using `rem_euclid` or similar function
`257`	`257`
`258`	`258`	`error: aborting due to 32 previous errors`
`259`	`259`