Sema: error on ambiguous coercion of comptime float and ints

The following, from the documentation as of the time of writing, illustrates
the problem:

```zig
// Compile time coercion of float to int
test "implicit cast to comptime_int" {
    var f: f32 = 54.0 / 5;
    _ = f;
}
```

It is not clear how to unify the types of 54.0 and 5 to perform the
division. We can either

 - cast 54.0 to comptime_int resulting in @as(comptime_int, 10), which is
   casted to @as(f32, 10), or
 - cast 5 to comptime_float resulting in @as(comptime_float, 10.8), which
   is casted to @as(f32, 10.8)

Since the two resulting values are different, a compiler error is appropriate.

If we know that casting to either type will result in the same value we
don't need to error.  For instance, 10.0 / 2 is okay, as is 10 / 2.0.

Fixes: #12364

1 files changed, 4 insertions, 4 deletions

diff --git a/test/behavior/floatop.zig b/test/behavior/floatop.zig
index c057f7a842..a5eb25d4f5 100644
--- a/test/behavior/floatop.zig
+++ b/test/behavior/floatop.zig
@@ -194,8 +194,8 @@ fn testSin() !void {
         const eps = epsForType(ty);
         try expect(@sin(@as(ty, 0)) == 0);
         try expect(math.approxEqAbs(ty, @sin(@as(ty, std.math.pi)), 0, eps));
-        try expect(math.approxEqAbs(ty, @sin(@as(ty, std.math.pi / 2)), 1, eps));
-        try expect(math.approxEqAbs(ty, @sin(@as(ty, std.math.pi / 4)), 0.7071067811865475, eps));
+        try expect(math.approxEqAbs(ty, @sin(@as(ty, std.math.pi / 2.0)), 1, eps));
+        try expect(math.approxEqAbs(ty, @sin(@as(ty, std.math.pi / 4.0)), 0.7071067811865475, eps));
     }
 
     {
@@ -228,8 +228,8 @@ fn testCos() !void {
         const eps = epsForType(ty);
         try expect(@cos(@as(ty, 0)) == 1);
         try expect(math.approxEqAbs(ty, @cos(@as(ty, std.math.pi)), -1, eps));
-        try expect(math.approxEqAbs(ty, @cos(@as(ty, std.math.pi / 2)), 0, eps));
-        try expect(math.approxEqAbs(ty, @cos(@as(ty, std.math.pi / 4)), 0.7071067811865475, eps));
+        try expect(math.approxEqAbs(ty, @cos(@as(ty, std.math.pi / 2.0)), 0, eps));
+        try expect(math.approxEqAbs(ty, @cos(@as(ty, std.math.pi / 4.0)), 0.7071067811865475, eps));
     }
 
     {