correct suggestion for manual_div_ceil lint (#13864)

fix #13843

The `manual_div_ceil` lint makes incorrect suggestion when type suffixes
need to be made explicit in the suggested code.

changelog: [`manual_div_ceil`]: suggested code now includes appropriate
type suffixes where necessary

Author: xFrednet

clippy_lints/src/manual_div_ceil.rs

@@ -2,14 +2,15 @@ use clippy_utils::SpanlessEq;
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::msrvs::{self, Msrv};
 use clippy_utils::source::snippet_with_applicability;
-use clippy_utils::sugg::Sugg;
-use rustc_ast::{BinOpKind, LitKind};
+use clippy_utils::sugg::{Sugg, has_enclosing_paren};
+use rustc_ast::{BinOpKind, LitIntType, LitKind, UnOp};
 use rustc_data_structures::packed::Pu128;
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::{self};
 use rustc_session::impl_lint_pass;
+use rustc_span::source_map::Spanned;
 use rustc_span::symbol::Symbol;
 
 use clippy_config::Conf;
@@ -138,9 +139,40 @@ fn build_suggestion(
     applicability: &mut Applicability,
 ) {
     let dividend_sugg = Sugg::hir_with_applicability(cx, lhs, "..", applicability).maybe_par();
+    let type_suffix = if cx.typeck_results().expr_ty(lhs).is_numeric()
+        && matches!(
+            lhs.kind,
+            ExprKind::Lit(Spanned {
+                node: LitKind::Int(_, LitIntType::Unsuffixed),
+                ..
+            }) | ExprKind::Unary(UnOp::Neg, Expr {
+                kind: ExprKind::Lit(Spanned {
+                    node: LitKind::Int(_, LitIntType::Unsuffixed),
+                    ..
+                }),
+                ..
+            })
+        ) {
+        format!("_{}", cx.typeck_results().expr_ty(rhs))
+    } else {
+        String::new()
+    };
+    let dividend_sugg_str = dividend_sugg.into_string();
+    // If `dividend_sugg` has enclosing paren like `(-2048)` and we need to add type suffix in the
+    // suggestion message, we want to make a suggestion string before `div_ceil` like
+    // `(-2048_{type_suffix})`.
+    let suggestion_before_div_ceil = if has_enclosing_paren(&dividend_sugg_str) {
+        format!(
+            "{}{})",
+            &dividend_sugg_str[..dividend_sugg_str.len() - 1].to_string(),
+            type_suffix
+        )
+    } else {
+        format!("{dividend_sugg_str}{type_suffix}")
+    };
     let divisor_snippet = snippet_with_applicability(cx, rhs.span.source_callsite(), "..", applicability);
 
-    let sugg = format!("{dividend_sugg}.div_ceil({divisor_snippet})");
+    let sugg = format!("{suggestion_before_div_ceil}.div_ceil({divisor_snippet})");
 
     span_lint_and_sugg(
         cx,

tests/ui/manual_div_ceil.fixed

@@ -28,3 +28,25 @@ fn main() {
     let _ = (7_u32 as i32 + (y_i - 1)) / y_i;
     let _ = (7_u32 as i32 + (4 - 1)) / 4;
 }
+
+fn issue_13843() {
+    let x = 3usize;
+    let _ = 2048_usize.div_ceil(x);
+
+    let x = 5usize;
+    let _ = 2048usize.div_ceil(x);
+
+    let x = 5usize;
+    let _ = 2048_usize.div_ceil(x);
+
+    let x = 2048usize;
+    let _ = x.div_ceil(4);
+
+    let _: u32 = 2048_u32.div_ceil(6);
+    let _: usize = 2048_usize.div_ceil(6);
+    let _: u32 = 0x2048_u32.div_ceil(0x6);
+
+    let _ = 2048_u32.div_ceil(6u32);
+
+    let _ = 1_000_000_u32.div_ceil(6u32);
+}

tests/ui/manual_div_ceil.rs

@@ -28,3 +28,25 @@ fn main() {
     let _ = (7_u32 as i32 + (y_i - 1)) / y_i;
     let _ = (7_u32 as i32 + (4 - 1)) / 4;
 }
+
+fn issue_13843() {
+    let x = 3usize;
+    let _ = (2048 + x - 1) / x;
+
+    let x = 5usize;
+    let _ = (2048usize + x - 1) / x;
+
+    let x = 5usize;
+    let _ = (2048_usize + x - 1) / x;
+
+    let x = 2048usize;
+    let _ = (x + 4 - 1) / 4;
+
+    let _: u32 = (2048 + 6 - 1) / 6;
+    let _: usize = (2048 + 6 - 1) / 6;
+    let _: u32 = (0x2048 + 0x6 - 1) / 0x6;
+
+    let _ = (2048 + 6u32 - 1) / 6u32;
+
+    let _ = (1_000_000 + 6u32 - 1) / 6u32;
+}

tests/ui/manual_div_ceil.stderr

@@ -31,5 +31,59 @@ error: manually reimplementing `div_ceil`
 LL |     let _ = (7_i32 as u32 + (4 - 1)) / 4;
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `(7_i32 as u32).div_ceil(4)`
 
-error: aborting due to 5 previous errors
+error: manually reimplementing `div_ceil`
+  --> tests/ui/manual_div_ceil.rs:34:13
+   |
+LL |     let _ = (2048 + x - 1) / x;
+   |             ^^^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `2048_usize.div_ceil(x)`
+
+error: manually reimplementing `div_ceil`
+  --> tests/ui/manual_div_ceil.rs:37:13
+   |
+LL |     let _ = (2048usize + x - 1) / x;
+   |             ^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `2048usize.div_ceil(x)`
+
+error: manually reimplementing `div_ceil`
+  --> tests/ui/manual_div_ceil.rs:40:13
+   |
+LL |     let _ = (2048_usize + x - 1) / x;
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `2048_usize.div_ceil(x)`
+
+error: manually reimplementing `div_ceil`
+  --> tests/ui/manual_div_ceil.rs:43:13
+   |
+LL |     let _ = (x + 4 - 1) / 4;
+   |             ^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `x.div_ceil(4)`
+
+error: manually reimplementing `div_ceil`
+  --> tests/ui/manual_div_ceil.rs:45:18
+   |
+LL |     let _: u32 = (2048 + 6 - 1) / 6;
+   |                  ^^^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `2048_u32.div_ceil(6)`
+
+error: manually reimplementing `div_ceil`
+  --> tests/ui/manual_div_ceil.rs:46:20
+   |
+LL |     let _: usize = (2048 + 6 - 1) / 6;
+   |                    ^^^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `2048_usize.div_ceil(6)`
+
+error: manually reimplementing `div_ceil`
+  --> tests/ui/manual_div_ceil.rs:47:18
+   |
+LL |     let _: u32 = (0x2048 + 0x6 - 1) / 0x6;
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `0x2048_u32.div_ceil(0x6)`
+
+error: manually reimplementing `div_ceil`
+  --> tests/ui/manual_div_ceil.rs:49:13
+   |
+LL |     let _ = (2048 + 6u32 - 1) / 6u32;
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `2048_u32.div_ceil(6u32)`
+
+error: manually reimplementing `div_ceil`
+  --> tests/ui/manual_div_ceil.rs:51:13
+   |
+LL |     let _ = (1_000_000 + 6u32 - 1) / 6u32;
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `1_000_000_u32.div_ceil(6u32)`
+
+error: aborting due to 14 previous errors
 

tests/ui/manual_div_ceil_with_feature.fixed

@@ -23,3 +23,30 @@ fn main() {
 
     let _ = (x + (y - 1)) / z;
 }
+
+fn issue_13843() {
+    let x = 3usize;
+    let _ = 2048_usize.div_ceil(x);
+
+    let x = 5usize;
+    let _ = 2048usize.div_ceil(x);
+
+    let x = 5usize;
+    let _ = 2048_usize.div_ceil(x);
+
+    let x = 2048usize;
+    let _ = x.div_ceil(4);
+
+    let _ = 2048_i32.div_ceil(4);
+
+    let _: u32 = 2048_u32.div_ceil(6);
+    let _: usize = 2048_usize.div_ceil(6);
+    let _: u32 = 0x2048_u32.div_ceil(0x6);
+
+    let _ = 2048_u32.div_ceil(6u32);
+
+    let x = -2;
+    let _ = (-2048_i32).div_ceil(x);
+
+    let _ = 1_000_000_u32.div_ceil(6u32);
+}

tests/ui/manual_div_ceil_with_feature.rs

@@ -23,3 +23,30 @@ fn main() {
 
     let _ = (x + (y - 1)) / z;
 }
+
+fn issue_13843() {
+    let x = 3usize;
+    let _ = (2048 + x - 1) / x;
+
+    let x = 5usize;
+    let _ = (2048usize + x - 1) / x;
+
+    let x = 5usize;
+    let _ = (2048_usize + x - 1) / x;
+
+    let x = 2048usize;
+    let _ = (x + 4 - 1) / 4;
+
+    let _ = (2048 + 4 - 1) / 4;
+
+    let _: u32 = (2048 + 6 - 1) / 6;
+    let _: usize = (2048 + 6 - 1) / 6;
+    let _: u32 = (0x2048 + 0x6 - 1) / 0x6;
+
+    let _ = (2048 + 6u32 - 1) / 6u32;
+
+    let x = -2;
+    let _ = (-2048 + x - 1) / x;
+
+    let _ = (1_000_000 + 6u32 - 1) / 6u32;
+}

tests/ui/manual_div_ceil_with_feature.stderr

@@ -43,5 +43,71 @@ error: manually reimplementing `div_ceil`
 LL |     let _ = (z_u + (4 - 1)) / 4;
    |             ^^^^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `z_u.div_ceil(4)`
 
-error: aborting due to 7 previous errors
+error: manually reimplementing `div_ceil`
+  --> tests/ui/manual_div_ceil_with_feature.rs:29:13
+   |
+LL |     let _ = (2048 + x - 1) / x;
+   |             ^^^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `2048_usize.div_ceil(x)`
+
+error: manually reimplementing `div_ceil`
+  --> tests/ui/manual_div_ceil_with_feature.rs:32:13
+   |
+LL |     let _ = (2048usize + x - 1) / x;
+   |             ^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `2048usize.div_ceil(x)`
+
+error: manually reimplementing `div_ceil`
+  --> tests/ui/manual_div_ceil_with_feature.rs:35:13
+   |
+LL |     let _ = (2048_usize + x - 1) / x;
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `2048_usize.div_ceil(x)`
+
+error: manually reimplementing `div_ceil`
+  --> tests/ui/manual_div_ceil_with_feature.rs:38:13
+   |
+LL |     let _ = (x + 4 - 1) / 4;
+   |             ^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `x.div_ceil(4)`
+
+error: manually reimplementing `div_ceil`
+  --> tests/ui/manual_div_ceil_with_feature.rs:40:13
+   |
+LL |     let _ = (2048 + 4 - 1) / 4;
+   |             ^^^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `2048_i32.div_ceil(4)`
+
+error: manually reimplementing `div_ceil`
+  --> tests/ui/manual_div_ceil_with_feature.rs:42:18
+   |
+LL |     let _: u32 = (2048 + 6 - 1) / 6;
+   |                  ^^^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `2048_u32.div_ceil(6)`
+
+error: manually reimplementing `div_ceil`
+  --> tests/ui/manual_div_ceil_with_feature.rs:43:20
+   |
+LL |     let _: usize = (2048 + 6 - 1) / 6;
+   |                    ^^^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `2048_usize.div_ceil(6)`
+
+error: manually reimplementing `div_ceil`
+  --> tests/ui/manual_div_ceil_with_feature.rs:44:18
+   |
+LL |     let _: u32 = (0x2048 + 0x6 - 1) / 0x6;
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `0x2048_u32.div_ceil(0x6)`
+
+error: manually reimplementing `div_ceil`
+  --> tests/ui/manual_div_ceil_with_feature.rs:46:13
+   |
+LL |     let _ = (2048 + 6u32 - 1) / 6u32;
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `2048_u32.div_ceil(6u32)`
+
+error: manually reimplementing `div_ceil`
+  --> tests/ui/manual_div_ceil_with_feature.rs:49:13
+   |
+LL |     let _ = (-2048 + x - 1) / x;
+   |             ^^^^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `(-2048_i32).div_ceil(x)`
+
+error: manually reimplementing `div_ceil`
+  --> tests/ui/manual_div_ceil_with_feature.rs:51:13
+   |
+LL |     let _ = (1_000_000 + 6u32 - 1) / 6u32;
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `1_000_000_u32.div_ceil(6u32)`
+
+error: aborting due to 18 previous errors