Auto merge of #57250 - codeworm96:tyerr_msg, r=varkor

Improve type mismatch error messages

Closes #56115.

Replace "integral variable" with "integer" and replace "floating-point variable" with "floating-point number" to make the message less confusing.

TODO the book and clippy needs to be changed accordingly later.

r? @varkor

Author: bors

src/librustc/ty/error.rs

@@ -200,8 +200,8 @@ impl<'a, 'gcx, 'lcx, 'tcx> ty::TyS<'tcx> {
             ty::GeneratorWitness(..) => "generator witness".into(),
             ty::Tuple(..) => "tuple".into(),
             ty::Infer(ty::TyVar(_)) => "inferred type".into(),
-            ty::Infer(ty::IntVar(_)) => "integral variable".into(),
-            ty::Infer(ty::FloatVar(_)) => "floating-point variable".into(),
+            ty::Infer(ty::IntVar(_)) => "integer".into(),
+            ty::Infer(ty::FloatVar(_)) => "floating-point number".into(),
             ty::Placeholder(..) => "placeholder type".into(),
             ty::Bound(..) => "bound type".into(),
             ty::Infer(ty::FreshTy(_)) => "fresh type".into(),

src/test/ui/bad/bad-const-type.rs

@@ -2,5 +2,5 @@ static i: String = 10;
 //~^ ERROR mismatched types
 //~| expected type `std::string::String`
 //~| found type `{integer}`
-//~| expected struct `std::string::String`, found integral variable
+//~| expected struct `std::string::String`, found integer
 fn main() { println!("{}", i); }