emit errors when using RangeFrom and RangeTo

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -1211,18 +1211,39 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
  expr: &hir::Expr<'_>,
  expected_ty: Ty<'tcx>,
  ) -> bool {
- if let ExprKind::Struct(QPath::LangItem(LangItem::Range, ..), [start, _], _) = expr.kind
- && expected_ty.is_floating_point()
- {
- err.span_suggestion_verbose(
- self.tcx.sess.source_map().next_point(start.span),
- "remove the unnecessary `.` operator to to use a floating point literal",
- "",
- Applicability::MachineApplicable,
- );
- return true;
+ if !expected_ty.is_floating_point() {
+ return false;
+ }
+ match expr.kind {
+ ExprKind::Struct(QPath::LangItem(LangItem::Range, ..), [start, end], _) => {
+ err.span_suggestion_verbose(
+ start.span.shrink_to_hi().with_hi(end.span.lo()),
+ "remove the unnecessary `.` operator for a floating point literal",
+ '.',
+ Applicability::MaybeIncorrect,
+ );
+ true
+ }
+ ExprKind::Struct(QPath::LangItem(LangItem::RangeFrom, ..), [start], _) => {
+ err.span_suggestion_verbose(
+ expr.span.with_lo(start.span.hi()),
+ "remove the unnecessary `.` operator for a floating point literal",
+ '.',
+ Applicability::MaybeIncorrect,
+ );
+ true
+ }
+ ExprKind::Struct(QPath::LangItem(LangItem::RangeTo, ..), [end], _) => {
+ err.span_suggestion_verbose(
+ expr.span.until(end.span),
+ "remove the unnecessary `.` operator and add an integer part for a floating point literal",
+ "0.",
+ Applicability::MaybeIncorrect,
+ );
+ true
+ }
+ _ => false,
  }
- false
  }
 
  fn is_loop(&self, id: hir::HirId) -> bool {

src/test/ui/suggestions/unnecessary_dot_for_floating_point_literal.rs

@@ -1,6 +1,6 @@
 fn main() {
  let _: f64 = 0..10; //~ ERROR mismatched types
- let _: f64 = 0..; //~ ERROR mismatched types
+ let _: f64 = 1..; //~ ERROR mismatched types
  let _: f64 = ..10; //~ ERROR mismatched types
  let _: f64 = std::ops::Range { start: 0, end: 1 }; //~ ERROR mismatched types
 }

src/test/ui/suggestions/unnecessary_dot_for_floating_point_literal.stderr

@@ -8,22 +8,25 @@ LL | let _: f64 = 0..10;
  |
  = note: expected type `f64`
  found struct `std::ops::Range<{integer}>`
-help: remove the unnecessary `.` operator to to use a floating point literal
- |
-LL - let _: f64 = 0..10;
-LL + let _: f64 = 0.10;
+help: remove the unnecessary `.` operator for a floating point literal
  |
+LL | let _: f64 = 0.10;
+ | ~
 
 error[E0308]: mismatched types
  --> $DIR/unnecessary_dot_for_floating_point_literal.rs:3:18
  |
-LL | let _: f64 = 0..;
+LL | let _: f64 = 1..;
  | --- ^^^ expected `f64`, found struct `RangeFrom`
  | |
  | expected due to this
  |
  = note: expected type `f64`
  found struct `RangeFrom<{integer}>`
+help: remove the unnecessary `.` operator for a floating point literal
+ |
+LL | let _: f64 = 1.;
+ | ~
 
 error[E0308]: mismatched types
  --> $DIR/unnecessary_dot_for_floating_point_literal.rs:4:18
@@ -35,6 +38,10 @@ LL | let _: f64 = ..10;
  |
  = note: expected type `f64`
  found struct `RangeTo<{integer}>`
+help: remove the unnecessary `.` operator and add an integer part for a floating point literal
+ |
+LL | let _: f64 = 0.10;
+ | ~~
 
 error[E0308]: mismatched types
  --> $DIR/unnecessary_dot_for_floating_point_literal.rs:5:18