Fix {subopt,imprec}_float not lint const.*(const)

Fixes #9402
Fixes #9201

Author: lukaslueg

clippy_lints/src/floating_point_arithmetic.rs

@@ -238,23 +238,23 @@ fn get_integer_from_float_constant(value: &Constant) -> Option<i32> {
 fn check_powf(cx: &LateContext<'_>, expr: &Expr<'_>, args: &[Expr<'_>]) {
     // Check receiver
     if let Some((value, _)) = constant(cx, cx.typeck_results(), &args[0]) {
-        let method = if F32(f32_consts::E) == value || F64(f64_consts::E) == value {
-            "exp"
+        if let Some(method) = if F32(f32_consts::E) == value || F64(f64_consts::E) == value {
+            Some("exp")
         } else if F32(2.0) == value || F64(2.0) == value {
-            "exp2"
+            Some("exp2")
         } else {
-            return;
-        };
-
-        span_lint_and_sugg(
-            cx,
-            SUBOPTIMAL_FLOPS,
-            expr.span,
-            "exponent for bases 2 and e can be computed more accurately",
-            "consider using",
-            format!("{}.{}()", prepare_receiver_sugg(cx, &args[1]), method),
-            Applicability::MachineApplicable,
-        );
+            None
+        } {
+            span_lint_and_sugg(
+                cx,
+                SUBOPTIMAL_FLOPS,
+                expr.span,
+                "exponent for bases 2 and e can be computed more accurately",
+                "consider using",
+                format!("{}.{}()", prepare_receiver_sugg(cx, &args[1]), method),
+                Applicability::MachineApplicable,
+            );
+        }
     }
 
     // Check argument

tests/ui/floating_point_powf.fixed

@@ -18,6 +18,11 @@ fn main() {
     let _ = x.powi(-16_777_215);
     let _ = (x as f32).powi(-16_777_215);
     let _ = (x as f32).powi(3);
+    let _ = (1.5_f32 + 1.0).cbrt();
+    let _ = 1.5_f64.cbrt();
+    let _ = 1.5_f64.sqrt();
+    let _ = 1.5_f64.powi(3);
+
     // Cases where the lint shouldn't be applied
     let _ = x.powf(2.1);
     let _ = x.powf(-2.1);

tests/ui/floating_point_powf.rs

@@ -18,6 +18,11 @@ fn main() {
     let _ = x.powf(-16_777_215.0);
     let _ = (x as f32).powf(-16_777_215.0);
     let _ = (x as f32).powf(3.0);
+    let _ = (1.5_f32 + 1.0).powf(1.0 / 3.0);
+    let _ = 1.5_f64.powf(1.0 / 3.0);
+    let _ = 1.5_f64.powf(1.0 / 2.0);
+    let _ = 1.5_f64.powf(3.0);
+
     // Cases where the lint shouldn't be applied
     let _ = x.powf(2.1);
     let _ = x.powf(-2.1);

tests/ui/floating_point_powf.stderr

@@ -92,77 +92,101 @@ error: exponentiation with integer powers can be computed more efficiently
 LL |     let _ = (x as f32).powf(3.0);
    |             ^^^^^^^^^^^^^^^^^^^^ help: consider using: `(x as f32).powi(3)`
 
+error: cube-root of a number can be computed more accurately
+  --> $DIR/floating_point_powf.rs:21:13
+   |
+LL |     let _ = (1.5_f32 + 1.0).powf(1.0 / 3.0);
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `(1.5_f32 + 1.0).cbrt()`
+
+error: cube-root of a number can be computed more accurately
+  --> $DIR/floating_point_powf.rs:22:13
+   |
+LL |     let _ = 1.5_f64.powf(1.0 / 3.0);
+   |             ^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `1.5_f64.cbrt()`
+
+error: square-root of a number can be computed more efficiently and accurately
+  --> $DIR/floating_point_powf.rs:23:13
+   |
+LL |     let _ = 1.5_f64.powf(1.0 / 2.0);
+   |             ^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `1.5_f64.sqrt()`
+
+error: exponentiation with integer powers can be computed more efficiently
+  --> $DIR/floating_point_powf.rs:24:13
+   |
+LL |     let _ = 1.5_f64.powf(3.0);
+   |             ^^^^^^^^^^^^^^^^^ help: consider using: `1.5_f64.powi(3)`
+
 error: exponent for bases 2 and e can be computed more accurately
-  --> $DIR/floating_point_powf.rs:28:13
+  --> $DIR/floating_point_powf.rs:33:13
    |
 LL |     let _ = 2f64.powf(x);
    |             ^^^^^^^^^^^^ help: consider using: `x.exp2()`
 
 error: exponent for bases 2 and e can be computed more accurately
-  --> $DIR/floating_point_powf.rs:29:13
+  --> $DIR/floating_point_powf.rs:34:13
    |
 LL |     let _ = 2f64.powf(3.1);
    |             ^^^^^^^^^^^^^^ help: consider using: `3.1f64.exp2()`
 
 error: exponent for bases 2 and e can be computed more accurately
-  --> $DIR/floating_point_powf.rs:30:13
+  --> $DIR/floating_point_powf.rs:35:13
    |
 LL |     let _ = 2f64.powf(-3.1);
    |             ^^^^^^^^^^^^^^^ help: consider using: `(-3.1f64).exp2()`
 
 error: exponent for bases 2 and e can be computed more accurately
-  --> $DIR/floating_point_powf.rs:31:13
+  --> $DIR/floating_point_powf.rs:36:13
    |
 LL |     let _ = std::f64::consts::E.powf(x);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.exp()`
 
 error: exponent for bases 2 and e can be computed more accurately
-  --> $DIR/floating_point_powf.rs:32:13
+  --> $DIR/floating_point_powf.rs:37:13
    |
 LL |     let _ = std::f64::consts::E.powf(3.1);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `3.1f64.exp()`
 
 error: exponent for bases 2 and e can be computed more accurately
-  --> $DIR/floating_point_powf.rs:33:13
+  --> $DIR/floating_point_powf.rs:38:13
    |
 LL |     let _ = std::f64::consts::E.powf(-3.1);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `(-3.1f64).exp()`
 
 error: square-root of a number can be computed more efficiently and accurately
-  --> $DIR/floating_point_powf.rs:34:13
+  --> $DIR/floating_point_powf.rs:39:13
    |
 LL |     let _ = x.powf(1.0 / 2.0);
    |             ^^^^^^^^^^^^^^^^^ help: consider using: `x.sqrt()`
 
 error: cube-root of a number can be computed more accurately
-  --> $DIR/floating_point_powf.rs:35:13
+  --> $DIR/floating_point_powf.rs:40:13
    |
 LL |     let _ = x.powf(1.0 / 3.0);
    |             ^^^^^^^^^^^^^^^^^ help: consider using: `x.cbrt()`
 
 error: exponentiation with integer powers can be computed more efficiently
-  --> $DIR/floating_point_powf.rs:36:13
+  --> $DIR/floating_point_powf.rs:41:13
    |
 LL |     let _ = x.powf(3.0);
    |             ^^^^^^^^^^^ help: consider using: `x.powi(3)`
 
 error: exponentiation with integer powers can be computed more efficiently
-  --> $DIR/floating_point_powf.rs:37:13
+  --> $DIR/floating_point_powf.rs:42:13
    |
 LL |     let _ = x.powf(-2.0);
    |             ^^^^^^^^^^^^ help: consider using: `x.powi(-2)`
 
 error: exponentiation with integer powers can be computed more efficiently
-  --> $DIR/floating_point_powf.rs:38:13
+  --> $DIR/floating_point_powf.rs:43:13
    |
 LL |     let _ = x.powf(-2_147_483_648.0);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.powi(-2_147_483_648)`
 
 error: exponentiation with integer powers can be computed more efficiently
-  --> $DIR/floating_point_powf.rs:39:13
+  --> $DIR/floating_point_powf.rs:44:13
    |
 LL |     let _ = x.powf(2_147_483_647.0);
    |             ^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.powi(2_147_483_647)`
 
-error: aborting due to 27 previous errors
+error: aborting due to 31 previous errors