Rollup merge of #124797 - beetrees:primitive-float, r=davidtwco

Refactor float `Primitive`s to a separate `Float` type

Now there are 4 of them, it makes sense to refactor `F16`, `F32`, `F64` and `F128` out of `Primitive` and into a separate `Float` type (like integers already are). This allows patterns like `F16 | F32 | F64 | F128` to be simplified into `Float(_)`, and is consistent with `ty::FloatTy`.

As a side effect, this PR also makes the `Ty::primitive_size` method work with `f16` and `f128`.

Tracking issue: #116909

`@rustbot` label +F-f16_and_f128

Author: matthiaskrgr

crates/hir-ty/src/layout.rs

@@ -6,8 +6,8 @@ use base_db::salsa::Cycle;
 use chalk_ir::{AdtId, FloatTy, IntTy, TyKind, UintTy};
 use hir_def::{
     layout::{
-        Abi, FieldsShape, Integer, LayoutCalculator, LayoutS, Primitive, ReprOptions, Scalar, Size,
-        StructKind, TargetDataLayout, WrappingRange,
+        Abi, FieldsShape, Float, Integer, LayoutCalculator, LayoutS, Primitive, ReprOptions,
+        Scalar, Size, StructKind, TargetDataLayout, WrappingRange,
     },
     LocalFieldId, StructId,
 };
@@ -264,10 +264,10 @@ pub fn layout_of_ty_query(
             ),
             chalk_ir::Scalar::Float(f) => scalar(
                 dl,
-                match f {
-                    FloatTy::F32 => Primitive::F32,
-                    FloatTy::F64 => Primitive::F64,
-                },
+                Primitive::Float(match f {
+                    FloatTy::F32 => Float::F32,
+                    FloatTy::F64 => Float::F64,
+                }),
             ),
         },
         TyKind::Tuple(len, tys) => {