expression: set floats as f64 by default

vlib/builtin/float_test.v

@@ -0,0 +1,34 @@
+fn test_float_decl() {
+  x1 := 1e10
+  x2 := -2e16
+  x3 := 1e-15
+  x4 := -9e-4
+  assert typeof(x1) == 'f64'
+  assert typeof(x2) == 'f64'
+  assert typeof(x3) == 'f64'
+  assert typeof(x4) == 'f64'
+  x5 := 4e108
+  x6 := -7e99
+  x7 := 3e-205
+  x8 := -6e-147
+  assert typeof(x5) == 'f64'
+  assert typeof(x6) == 'f64'
+  assert typeof(x7) == 'f64'
+  assert typeof(x8) == 'f64'
+  x9 := 312874834.77
+  x10 := -22399994.06
+  x11 := 0.0000000019
+  x12 := -0.00000000008
+  assert typeof(x9) == 'f64'
+  assert typeof(x10) == 'f64'
+  assert typeof(x11) == 'f64'
+  assert typeof(x12) == 'f64'
+  x13 := 34234234809890890898903213154353453453253253243432413232228908902183918392183902432432438980380123021983901392183921389083913890389089031.0
+  x14 := -39999999999999999999222212128182813294989082302832183928343325325233253242312331324392839238239829389038097438248932789371837218372837293.8
+  x15 := 0.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000002
+  x16 := -0.00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000004
+  assert typeof(x13) == 'f64'
+  assert typeof(x14) == 'f64'
+  assert typeof(x15) == 'f64'
+  assert typeof(x16) == 'f64'
+}