1 files changed, 47 insertions, 0 deletions
diff --git a/test/float_lit3.go b/test/float_lit3.go
new file mode 100644
index 0000000..37a1289
--- /dev/null
+++ b/test/float_lit3.go
@@ -0,0 +1,47 @@
+// errorcheck
+
+// Check flagging of invalid conversion of constant to float32/float64 near min/max boundaries.
+
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+// See float_lit2.go for motivation for these values.
+const (
+	two24   = 1.0 * (1 << 24)
+	two53   = 1.0 * (1 << 53)
+	two64   = 1.0 * (1 << 64)
+	two128  = two64 * two64
+	two256  = two128 * two128
+	two512  = two256 * two256
+	two768  = two512 * two256
+	two1024 = two512 * two512
+
+	ulp32 = two128 / two24
+	max32 = two128 - ulp32
+
+	ulp64 = two1024 / two53
+	max64 = two1024 - ulp64
+)
+
+var x = []interface{}{
+	float32(max32 + ulp32/2 - 1),             // ok
+	float32(max32 + ulp32/2 - two128/two256), // ok
+	float32(max32 + ulp32/2),                 // ERROR "constant 3\.40282e\+38 overflows float32|cannot convert.*to type float32"
+
+	float32(-max32 - ulp32/2 + 1),             // ok
+	float32(-max32 - ulp32/2 + two128/two256), // ok
+	float32(-max32 - ulp32/2),                 // ERROR "constant -3\.40282e\+38 overflows float32|cannot convert.*to type float32"
+
+	// If the compiler's internal floating point representation
+	// is shorter than 1024 bits, it cannot distinguish max64+ulp64/2-1 and max64+ulp64/2.
+	float64(max64 + ulp64/2 - two1024/two256), // ok
+	float64(max64 + ulp64/2 - 1),              // ok
+	float64(max64 + ulp64/2),                  // ERROR "constant 1\.79769e\+308 overflows float64|cannot convert.*to type float64"
+
+	float64(-max64 - ulp64/2 + two1024/two256), // ok
+	float64(-max64 - ulp64/2 + 1),              // ok
+	float64(-max64 - ulp64/2),                  // ERROR "constant -1\.79769e\+308 overflows float64|cannot convert.*to type float64"
+}