diff --git a/src/librustc_typeck/check/demand.rs b/src/librustc_typeck/check/demand.rs index 019b4ca66060c..bcfc0cf347cbc 100644 --- a/src/librustc_typeck/check/demand.rs +++ b/src/librustc_typeck/check/demand.rs @@ -783,6 +783,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { let literal_is_ty_suffixed = |expr: &hir::Expr<'_>| { if let hir::ExprKind::Lit(lit) = &expr.kind { lit.node.is_suffixed() } else { false } }; + let is_negative_int = + |expr: &hir::Expr<'_>| matches!(expr.kind, hir::ExprKind::Unary(hir::UnOp::UnNeg, ..)); + let is_uint = |ty: Ty<'_>| matches!(ty.kind, ty::Uint(..)); let in_const_context = self.tcx.hir().is_inside_const_context(expr.hir_id); @@ -807,7 +810,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { "you can convert `{}` from `{}` to `{}`, matching the type of `{}`", lhs_src, expected_ty, checked_ty, src ); - let suggestion = format!("{}::from({})", checked_ty, lhs_src,); + let suggestion = format!("{}::from({})", checked_ty, lhs_src); (lhs_expr.span, msg, suggestion) } else { let msg = format!("{} and panic if the converted value wouldn't fit", msg); @@ -822,8 +825,17 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { |err: &mut DiagnosticBuilder<'_>, found_to_exp_is_fallible: bool, exp_to_found_is_fallible: bool| { + let always_fallible = found_to_exp_is_fallible + && (exp_to_found_is_fallible || expected_ty_expr.is_none()); let msg = if literal_is_ty_suffixed(expr) { &lit_msg + } else if always_fallible && (is_negative_int(expr) && is_uint(expected_ty)) { + // We now know that converting either the lhs or rhs is fallible. Before we + // suggest a fallible conversion, check if the value can never fit in the + // expected type. + let msg = format!("`{}` cannot fit into type `{}`", src, expected_ty); + err.note(&msg); + return; } else if in_const_context { // Do not recommend `into` or `try_into` in const contexts. return; diff --git a/src/test/ui/numeric/numeric-cast-no-fix.rs b/src/test/ui/numeric/numeric-cast-no-fix.rs new file mode 100644 index 0000000000000..63e5f098a25d3 --- /dev/null +++ b/src/test/ui/numeric/numeric-cast-no-fix.rs @@ -0,0 +1,87 @@ +#[allow(unused_must_use)] +fn main() { + let x_usize: usize = 1; + let x_u128: u128 = 2; + let x_u64: u64 = 3; + let x_u32: u32 = 4; + let x_u16: u16 = 5; + let x_u8: u8 = 6; + + x_usize > -1_isize; + //~^ ERROR mismatched types + x_u128 > -1_isize; + //~^ ERROR mismatched types + x_u64 > -1_isize; + //~^ ERROR mismatched types + x_u32 > -1_isize; + //~^ ERROR mismatched types + x_u16 > -1_isize; + //~^ ERROR mismatched types + x_u8 > -1_isize; + //~^ ERROR mismatched types + + x_usize > -1_i128; + //~^ ERROR mismatched types + x_u128 > -1_i128; + //~^ ERROR mismatched types + x_u64 > -1_i128; + //~^ ERROR mismatched types + x_u32 > -1_i128; + //~^ ERROR mismatched types + x_u16 > -1_i128; + //~^ ERROR mismatched types + x_u8 > -1_i128; + //~^ ERROR mismatched types + + x_usize > -1_i64; + //~^ ERROR mismatched types + x_u128 > -1_i64; + //~^ ERROR mismatched types + x_u64 > -1_i64; + //~^ ERROR mismatched types + x_u32 > -1_i64; + //~^ ERROR mismatched types + x_u16 > -1_i64; + //~^ ERROR mismatched types + x_u8 > -1_i64; + //~^ ERROR mismatched types + + x_usize > -1_i32; + //~^ ERROR mismatched types + x_u128 > -1_i32; + //~^ ERROR mismatched types + x_u64 > -1_i32; + //~^ ERROR mismatched types + x_u32 > -1_i32; + //~^ ERROR mismatched types + x_u16 > -1_i32; + //~^ ERROR mismatched types + x_u8 > -1_i32; + //~^ ERROR mismatched types + + x_usize > -1_i16; + //~^ ERROR mismatched types + x_u128 > -1_i16; + //~^ ERROR mismatched types + x_u64 > -1_i16; + //~^ ERROR mismatched types + x_u32 > -1_i16; + //~^ ERROR mismatched types + x_u16 > -1_i16; + //~^ ERROR mismatched types + x_u8 > -1_i16; + //~^ ERROR mismatched types + + x_usize > -1_i8; + //~^ ERROR mismatched types + x_u128 > -1_i8; + //~^ ERROR mismatched types + x_u64 > -1_i8; + //~^ ERROR mismatched types + x_u32 > -1_i8; + //~^ ERROR mismatched types + x_u16 > -1_i8; + //~^ ERROR mismatched types + x_u8 > -1_i8; + //~^ ERROR mismatched types +} diff --git a/src/test/ui/numeric/numeric-cast-no-fix.stderr b/src/test/ui/numeric/numeric-cast-no-fix.stderr new file mode 100644 index 0000000000000..4852e7047b47a --- /dev/null +++ b/src/test/ui/numeric/numeric-cast-no-fix.stderr @@ -0,0 +1,324 @@ +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:10:15 + | +LL | x_usize > -1_isize; + | ^^^^^^^^ expected `usize`, found `isize` + | + = note: `-1_isize` cannot fit into type `usize` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:12:14 + | +LL | x_u128 > -1_isize; + | ^^^^^^^^ expected `u128`, found `isize` + | + = note: `-1_isize` cannot fit into type `u128` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:14:13 + | +LL | x_u64 > -1_isize; + | ^^^^^^^^ expected `u64`, found `isize` + | + = note: `-1_isize` cannot fit into type `u64` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:16:13 + | +LL | x_u32 > -1_isize; + | ^^^^^^^^ expected `u32`, found `isize` + | + = note: `-1_isize` cannot fit into type `u32` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:18:13 + | +LL | x_u16 > -1_isize; + | ^^^^^^^^ expected `u16`, found `isize` + | + = note: `-1_isize` cannot fit into type `u16` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:20:12 + | +LL | x_u8 > -1_isize; + | ^^^^^^^^ expected `u8`, found `isize` + | +help: you can convert `x_u8` from `u8` to `isize`, matching the type of `-1_isize` + | +LL | isize::from(x_u8) > -1_isize; + | ^^^^^^^^^^^^^^^^^ + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:23:15 + | +LL | x_usize > -1_i128; + | ^^^^^^^ expected `usize`, found `i128` + | + = note: `-1_i128` cannot fit into type `usize` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:25:14 + | +LL | x_u128 > -1_i128; + | ^^^^^^^ expected `u128`, found `i128` + | + = note: `-1_i128` cannot fit into type `u128` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:27:13 + | +LL | x_u64 > -1_i128; + | ^^^^^^^ expected `u64`, found `i128` + | +help: you can convert `x_u64` from `u64` to `i128`, matching the type of `-1_i128` + | +LL | i128::from(x_u64) > -1_i128; + | ^^^^^^^^^^^^^^^^^ + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:29:13 + | +LL | x_u32 > -1_i128; + | ^^^^^^^ expected `u32`, found `i128` + | +help: you can convert `x_u32` from `u32` to `i128`, matching the type of `-1_i128` + | +LL | i128::from(x_u32) > -1_i128; + | ^^^^^^^^^^^^^^^^^ + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:31:13 + | +LL | x_u16 > -1_i128; + | ^^^^^^^ expected `u16`, found `i128` + | +help: you can convert `x_u16` from `u16` to `i128`, matching the type of `-1_i128` + | +LL | i128::from(x_u16) > -1_i128; + | ^^^^^^^^^^^^^^^^^ + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:33:12 + | +LL | x_u8 > -1_i128; + | ^^^^^^^ expected `u8`, found `i128` + | +help: you can convert `x_u8` from `u8` to `i128`, matching the type of `-1_i128` + | +LL | i128::from(x_u8) > -1_i128; + | ^^^^^^^^^^^^^^^^ + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:36:15 + | +LL | x_usize > -1_i64; + | ^^^^^^ expected `usize`, found `i64` + | + = note: `-1_i64` cannot fit into type `usize` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:38:14 + | +LL | x_u128 > -1_i64; + | ^^^^^^ expected `u128`, found `i64` + | + = note: `-1_i64` cannot fit into type `u128` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:40:13 + | +LL | x_u64 > -1_i64; + | ^^^^^^ expected `u64`, found `i64` + | + = note: `-1_i64` cannot fit into type `u64` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:42:13 + | +LL | x_u32 > -1_i64; + | ^^^^^^ expected `u32`, found `i64` + | +help: you can convert `x_u32` from `u32` to `i64`, matching the type of `-1_i64` + | +LL | i64::from(x_u32) > -1_i64; + | ^^^^^^^^^^^^^^^^ + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:44:13 + | +LL | x_u16 > -1_i64; + | ^^^^^^ expected `u16`, found `i64` + | +help: you can convert `x_u16` from `u16` to `i64`, matching the type of `-1_i64` + | +LL | i64::from(x_u16) > -1_i64; + | ^^^^^^^^^^^^^^^^ + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:46:12 + | +LL | x_u8 > -1_i64; + | ^^^^^^ expected `u8`, found `i64` + | +help: you can convert `x_u8` from `u8` to `i64`, matching the type of `-1_i64` + | +LL | i64::from(x_u8) > -1_i64; + | ^^^^^^^^^^^^^^^ + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:49:15 + | +LL | x_usize > -1_i32; + | ^^^^^^ expected `usize`, found `i32` + | + = note: `-1_i32` cannot fit into type `usize` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:51:14 + | +LL | x_u128 > -1_i32; + | ^^^^^^ expected `u128`, found `i32` + | + = note: `-1_i32` cannot fit into type `u128` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:53:13 + | +LL | x_u64 > -1_i32; + | ^^^^^^ expected `u64`, found `i32` + | + = note: `-1_i32` cannot fit into type `u64` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:55:13 + | +LL | x_u32 > -1_i32; + | ^^^^^^ expected `u32`, found `i32` + | + = note: `-1_i32` cannot fit into type `u32` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:57:13 + | +LL | x_u16 > -1_i32; + | ^^^^^^ expected `u16`, found `i32` + | +help: you can convert `x_u16` from `u16` to `i32`, matching the type of `-1_i32` + | +LL | i32::from(x_u16) > -1_i32; + | ^^^^^^^^^^^^^^^^ + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:59:12 + | +LL | x_u8 > -1_i32; + | ^^^^^^ expected `u8`, found `i32` + | +help: you can convert `x_u8` from `u8` to `i32`, matching the type of `-1_i32` + | +LL | i32::from(x_u8) > -1_i32; + | ^^^^^^^^^^^^^^^ + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:62:15 + | +LL | x_usize > -1_i16; + | ^^^^^^ expected `usize`, found `i16` + | + = note: `-1_i16` cannot fit into type `usize` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:64:14 + | +LL | x_u128 > -1_i16; + | ^^^^^^ expected `u128`, found `i16` + | + = note: `-1_i16` cannot fit into type `u128` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:66:13 + | +LL | x_u64 > -1_i16; + | ^^^^^^ expected `u64`, found `i16` + | + = note: `-1_i16` cannot fit into type `u64` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:68:13 + | +LL | x_u32 > -1_i16; + | ^^^^^^ expected `u32`, found `i16` + | + = note: `-1_i16` cannot fit into type `u32` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:70:13 + | +LL | x_u16 > -1_i16; + | ^^^^^^ expected `u16`, found `i16` + | + = note: `-1_i16` cannot fit into type `u16` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:72:12 + | +LL | x_u8 > -1_i16; + | ^^^^^^ expected `u8`, found `i16` + | +help: you can convert `x_u8` from `u8` to `i16`, matching the type of `-1_i16` + | +LL | i16::from(x_u8) > -1_i16; + | ^^^^^^^^^^^^^^^ + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:75:15 + | +LL | x_usize > -1_i8; + | ^^^^^ expected `usize`, found `i8` + | + = note: `-1_i8` cannot fit into type `usize` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:77:14 + | +LL | x_u128 > -1_i8; + | ^^^^^ expected `u128`, found `i8` + | + = note: `-1_i8` cannot fit into type `u128` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:79:13 + | +LL | x_u64 > -1_i8; + | ^^^^^ expected `u64`, found `i8` + | + = note: `-1_i8` cannot fit into type `u64` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:81:13 + | +LL | x_u32 > -1_i8; + | ^^^^^ expected `u32`, found `i8` + | + = note: `-1_i8` cannot fit into type `u32` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:83:13 + | +LL | x_u16 > -1_i8; + | ^^^^^ expected `u16`, found `i8` + | + = note: `-1_i8` cannot fit into type `u16` + +error[E0308]: mismatched types + --> $DIR/numeric-cast-no-fix.rs:85:12 + | +LL | x_u8 > -1_i8; + | ^^^^^ expected `u8`, found `i8` + | + = note: `-1_i8` cannot fit into type `u8` + +error: aborting due to 36 previous errors + +For more information about this error, try `rustc --explain E0308`. diff --git a/src/test/ui/repeat_count.stderr b/src/test/ui/repeat_count.stderr index 6a081e23d9d37..2eab3ebc7687d 100644 --- a/src/test/ui/repeat_count.stderr +++ b/src/test/ui/repeat_count.stderr @@ -39,12 +39,16 @@ error[E0308]: mismatched types | LL | let f = [0; -4_isize]; | ^^^^^^^^ expected `usize`, found `isize` + | + = note: `-4_isize` cannot fit into type `usize` error[E0308]: mismatched types --> $DIR/repeat_count.rs:22:23 | LL | let f = [0_usize; -1_isize]; | ^^^^^^^^ expected `usize`, found `isize` + | + = note: `-1_isize` cannot fit into type `usize` error[E0308]: mismatched types --> $DIR/repeat_count.rs:25:17