suggest a float literal when dividing a floating-point type by {integer}

fix a message

implement a rustfix-applicable suggestion

implement `suggest_floating_point_literal`

add `ObligationCauseCode::BinOp`

remove duplicate code

fix function names in uitests

use `Diagnostic` instead of `DiagnosticBuilder`

6 files changed, 329 insertions, 0 deletions

diff --git a/src/test/ui/issues/issue-24352.stderr b/src/test/ui/issues/issue-24352.stderr
index 69cd7789065..69731bfe7ee 100644
--- a/src/test/ui/issues/issue-24352.stderr
+++ b/src/test/ui/issues/issue-24352.stderr
@@ -5,6 +5,10 @@ LL |     1.0f64 - 1
    |            ^ no implementation for `f64 - {integer}`
    |
    = help: the trait `Sub<{integer}>` is not implemented for `f64`
+help: consider using a floating-point literal by writing it with `.0`
+   |
+LL |     1.0f64 - 1.0
+   |               ++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/numbers-arithmetic/not-suggest-float-literal.rs b/src/test/ui/numbers-arithmetic/not-suggest-float-literal.rs
new file mode 100644
index 00000000000..513d02db988
--- /dev/null
+++ b/src/test/ui/numbers-arithmetic/not-suggest-float-literal.rs
@@ -0,0 +1,53 @@
+fn add_float_to_integer(x: u8) -> f32 {
+    x + 100.0 //~ ERROR cannot add `{float}` to `u8`
+}
+
+fn add_str_to_float(x: f64) -> f64 {
+    x + "foo" //~ ERROR cannot add `&str` to `f64`
+}
+
+fn add_lvar_to_float(x: f64) -> f64 {
+    let y = 3;
+    x + y //~ ERROR cannot add `{integer}` to `f64`
+}
+
+fn subtract_float_from_integer(x: u8) -> f32 {
+    x - 100.0 //~ ERROR cannot subtract `{float}` from `u8`
+}
+
+fn subtract_str_from_f64(x: f64) -> f64 {
+    x - "foo" //~ ERROR cannot subtract `&str` from `f64`
+}
+
+fn subtract_lvar_from_f64(x: f64) -> f64 {
+    let y = 3;
+    x - y //~ ERROR cannot subtract `{integer}` from `f64`
+}
+
+fn multiply_integer_by_float(x: u8) -> f32 {
+    x * 100.0 //~ ERROR cannot multiply `u8` by `{float}`
+}
+
+fn multiply_f64_by_str(x: f64) -> f64 {
+    x * "foo" //~ ERROR cannot multiply `f64` by `&str`
+}
+
+fn multiply_f64_by_lvar(x: f64) -> f64 {
+    let y = 3;
+    x * y //~ ERROR cannot multiply `f64` by `{integer}`
+}
+
+fn divide_integer_by_float(x: u8) -> u8 {
+    x / 100.0 //~ ERROR cannot divide `u8` by `{float}`
+}
+
+fn divide_f64_by_str(x: f64) -> f64 {
+    x / "foo" //~ ERROR cannot divide `f64` by `&str`
+}
+
+fn divide_f64_by_lvar(x: f64) -> f64 {
+    let y = 3;
+    x / y //~ ERROR cannot divide `f64` by `{integer}`
+}
+
+fn main() {}
diff --git a/src/test/ui/numbers-arithmetic/not-suggest-float-literal.stderr b/src/test/ui/numbers-arithmetic/not-suggest-float-literal.stderr
new file mode 100644
index 00000000000..ce9a08a1589
--- /dev/null
+++ b/src/test/ui/numbers-arithmetic/not-suggest-float-literal.stderr
@@ -0,0 +1,99 @@
+error[E0277]: cannot add `{float}` to `u8`
+  --> $DIR/not-suggest-float-literal.rs:2:7
+   |
+LL |     x + 100.0
+   |       ^ no implementation for `u8 + {float}`
+   |
+   = help: the trait `Add<{float}>` is not implemented for `u8`
+
+error[E0277]: cannot add `&str` to `f64`
+  --> $DIR/not-suggest-float-literal.rs:6:7
+   |
+LL |     x + "foo"
+   |       ^ no implementation for `f64 + &str`
+   |
+   = help: the trait `Add<&str>` is not implemented for `f64`
+
+error[E0277]: cannot add `{integer}` to `f64`
+  --> $DIR/not-suggest-float-literal.rs:11:7
+   |
+LL |     x + y
+   |       ^ no implementation for `f64 + {integer}`
+   |
+   = help: the trait `Add<{integer}>` is not implemented for `f64`
+
+error[E0277]: cannot subtract `{float}` from `u8`
+  --> $DIR/not-suggest-float-literal.rs:15:7
+   |
+LL |     x - 100.0
+   |       ^ no implementation for `u8 - {float}`
+   |
+   = help: the trait `Sub<{float}>` is not implemented for `u8`
+
+error[E0277]: cannot subtract `&str` from `f64`
+  --> $DIR/not-suggest-float-literal.rs:19:7
+   |
+LL |     x - "foo"
+   |       ^ no implementation for `f64 - &str`
+   |
+   = help: the trait `Sub<&str>` is not implemented for `f64`
+
+error[E0277]: cannot subtract `{integer}` from `f64`
+  --> $DIR/not-suggest-float-literal.rs:24:7
+   |
+LL |     x - y
+   |       ^ no implementation for `f64 - {integer}`
+   |
+   = help: the trait `Sub<{integer}>` is not implemented for `f64`
+
+error[E0277]: cannot multiply `u8` by `{float}`
+  --> $DIR/not-suggest-float-literal.rs:28:7
+   |
+LL |     x * 100.0
+   |       ^ no implementation for `u8 * {float}`
+   |
+   = help: the trait `Mul<{float}>` is not implemented for `u8`
+
+error[E0277]: cannot multiply `f64` by `&str`
+  --> $DIR/not-suggest-float-literal.rs:32:7
+   |
+LL |     x * "foo"
+   |       ^ no implementation for `f64 * &str`
+   |
+   = help: the trait `Mul<&str>` is not implemented for `f64`
+
+error[E0277]: cannot multiply `f64` by `{integer}`
+  --> $DIR/not-suggest-float-literal.rs:37:7
+   |
+LL |     x * y
+   |       ^ no implementation for `f64 * {integer}`
+   |
+   = help: the trait `Mul<{integer}>` is not implemented for `f64`
+
+error[E0277]: cannot divide `u8` by `{float}`
+  --> $DIR/not-suggest-float-literal.rs:41:7
+   |
+LL |     x / 100.0
+   |       ^ no implementation for `u8 / {float}`
+   |
+   = help: the trait `Div<{float}>` is not implemented for `u8`
+
+error[E0277]: cannot divide `f64` by `&str`
+  --> $DIR/not-suggest-float-literal.rs:45:7
+   |
+LL |     x / "foo"
+   |       ^ no implementation for `f64 / &str`
+   |
+   = help: the trait `Div<&str>` is not implemented for `f64`
+
+error[E0277]: cannot divide `f64` by `{integer}`
+  --> $DIR/not-suggest-float-literal.rs:50:7
+   |
+LL |     x / y
+   |       ^ no implementation for `f64 / {integer}`
+   |
+   = help: the trait `Div<{integer}>` is not implemented for `f64`
+
+error: aborting due to 12 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/numbers-arithmetic/suggest-float-literal.fixed b/src/test/ui/numbers-arithmetic/suggest-float-literal.fixed
new file mode 100644
index 00000000000..9278262a6ff
--- /dev/null
+++ b/src/test/ui/numbers-arithmetic/suggest-float-literal.fixed
@@ -0,0 +1,37 @@
+// run-rustfix
+
+#![allow(dead_code)]
+
+fn add_integer_to_f32(x: f32) -> f32 {
+    x + 100.0 //~ ERROR cannot add `{integer}` to `f32`
+}
+
+fn add_integer_to_f64(x: f64) -> f64 {
+    x + 100.0 //~ ERROR cannot add `{integer}` to `f64`
+}
+
+fn subtract_integer_from_f32(x: f32) -> f32 {
+    x - 100.0 //~ ERROR cannot subtract `{integer}` from `f32`
+}
+
+fn subtract_integer_from_f64(x: f64) -> f64 {
+    x - 100.0 //~ ERROR cannot subtract `{integer}` from `f64`
+}
+
+fn multiply_f32_by_integer(x: f32) -> f32 {
+    x * 100.0 //~ ERROR cannot multiply `f32` by `{integer}`
+}
+
+fn multiply_f64_by_integer(x: f64) -> f64 {
+    x * 100.0 //~ ERROR cannot multiply `f64` by `{integer}`
+}
+
+fn divide_f32_by_integer(x: f32) -> f32 {
+    x / 100.0 //~ ERROR cannot divide `f32` by `{integer}`
+}
+
+fn divide_f64_by_integer(x: f64) -> f64 {
+    x / 100.0 //~ ERROR cannot divide `f64` by `{integer}`
+}
+
+fn main() {}
diff --git a/src/test/ui/numbers-arithmetic/suggest-float-literal.rs b/src/test/ui/numbers-arithmetic/suggest-float-literal.rs
new file mode 100644
index 00000000000..59e67f8d33e
--- /dev/null
+++ b/src/test/ui/numbers-arithmetic/suggest-float-literal.rs
@@ -0,0 +1,37 @@
+// run-rustfix
+
+#![allow(dead_code)]
+
+fn add_integer_to_f32(x: f32) -> f32 {
+    x + 100 //~ ERROR cannot add `{integer}` to `f32`
+}
+
+fn add_integer_to_f64(x: f64) -> f64 {
+    x + 100 //~ ERROR cannot add `{integer}` to `f64`
+}
+
+fn subtract_integer_from_f32(x: f32) -> f32 {
+    x - 100 //~ ERROR cannot subtract `{integer}` from `f32`
+}
+
+fn subtract_integer_from_f64(x: f64) -> f64 {
+    x - 100 //~ ERROR cannot subtract `{integer}` from `f64`
+}
+
+fn multiply_f32_by_integer(x: f32) -> f32 {
+    x * 100 //~ ERROR cannot multiply `f32` by `{integer}`
+}
+
+fn multiply_f64_by_integer(x: f64) -> f64 {
+    x * 100 //~ ERROR cannot multiply `f64` by `{integer}`
+}
+
+fn divide_f32_by_integer(x: f32) -> f32 {
+    x / 100 //~ ERROR cannot divide `f32` by `{integer}`
+}
+
+fn divide_f64_by_integer(x: f64) -> f64 {
+    x / 100 //~ ERROR cannot divide `f64` by `{integer}`
+}
+
+fn main() {}
diff --git a/src/test/ui/numbers-arithmetic/suggest-float-literal.stderr b/src/test/ui/numbers-arithmetic/suggest-float-literal.stderr
new file mode 100644
index 00000000000..eb0be785061
--- /dev/null
+++ b/src/test/ui/numbers-arithmetic/suggest-float-literal.stderr
@@ -0,0 +1,99 @@
+error[E0277]: cannot add `{integer}` to `f32`
+  --> $DIR/suggest-float-literal.rs:6:7
+   |
+LL |     x + 100
+   |       ^ no implementation for `f32 + {integer}`
+   |
+   = help: the trait `Add<{integer}>` is not implemented for `f32`
+help: consider using a floating-point literal by writing it with `.0`
+   |
+LL |     x + 100.0
+   |            ++
+
+error[E0277]: cannot add `{integer}` to `f64`
+  --> $DIR/suggest-float-literal.rs:10:7
+   |
+LL |     x + 100
+   |       ^ no implementation for `f64 + {integer}`
+   |
+   = help: the trait `Add<{integer}>` is not implemented for `f64`
+help: consider using a floating-point literal by writing it with `.0`
+   |
+LL |     x + 100.0
+   |            ++
+
+error[E0277]: cannot subtract `{integer}` from `f32`
+  --> $DIR/suggest-float-literal.rs:14:7
+   |
+LL |     x - 100
+   |       ^ no implementation for `f32 - {integer}`
+   |
+   = help: the trait `Sub<{integer}>` is not implemented for `f32`
+help: consider using a floating-point literal by writing it with `.0`
+   |
+LL |     x - 100.0
+   |            ++
+
+error[E0277]: cannot subtract `{integer}` from `f64`
+  --> $DIR/suggest-float-literal.rs:18:7
+   |
+LL |     x - 100
+   |       ^ no implementation for `f64 - {integer}`
+   |
+   = help: the trait `Sub<{integer}>` is not implemented for `f64`
+help: consider using a floating-point literal by writing it with `.0`
+   |
+LL |     x - 100.0
+   |            ++
+
+error[E0277]: cannot multiply `f32` by `{integer}`
+  --> $DIR/suggest-float-literal.rs:22:7
+   |
+LL |     x * 100
+   |       ^ no implementation for `f32 * {integer}`
+   |
+   = help: the trait `Mul<{integer}>` is not implemented for `f32`
+help: consider using a floating-point literal by writing it with `.0`
+   |
+LL |     x * 100.0
+   |            ++
+
+error[E0277]: cannot multiply `f64` by `{integer}`
+  --> $DIR/suggest-float-literal.rs:26:7
+   |
+LL |     x * 100
+   |       ^ no implementation for `f64 * {integer}`
+   |
+   = help: the trait `Mul<{integer}>` is not implemented for `f64`
+help: consider using a floating-point literal by writing it with `.0`
+   |
+LL |     x * 100.0
+   |            ++
+
+error[E0277]: cannot divide `f32` by `{integer}`
+  --> $DIR/suggest-float-literal.rs:30:7
+   |
+LL |     x / 100
+   |       ^ no implementation for `f32 / {integer}`
+   |
+   = help: the trait `Div<{integer}>` is not implemented for `f32`
+help: consider using a floating-point literal by writing it with `.0`
+   |
+LL |     x / 100.0
+   |            ++
+
+error[E0277]: cannot divide `f64` by `{integer}`
+  --> $DIR/suggest-float-literal.rs:34:7
+   |
+LL |     x / 100
+   |       ^ no implementation for `f64 / {integer}`
+   |
+   = help: the trait `Div<{integer}>` is not implemented for `f64`
+help: consider using a floating-point literal by writing it with `.0`
+   |
+LL |     x / 100.0
+   |            ++
+
+error: aborting due to 8 previous errors
+
+For more information about this error, try `rustc --explain E0277`.