From fea56d4164ba832dd0f6798cb267ac2fe8b6321a Mon Sep 17 00:00:00 2001
From: Ayke van Laethem <aykevanlaethem@gmail.com>
Date: Sun, 11 Aug 2019 14:30:43 +0200
Subject: [PATCH] compiler: add support for full slice expression for slicing
 arrays

This was an oversight in the main commit for full slice expressions:
https://github.com/tinygo-org/tinygo/pull/472
This syntax is used by the regexp package, for example.
---
 compiler/compiler.go |  3 ---
 testdata/slice.go    | 13 +++++++++++++
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/compiler/compiler.go b/compiler/compiler.go
index ed5b8c8d..f6a583ef 100644
--- a/compiler/compiler.go
+++ b/compiler/compiler.go
@@ -1776,9 +1776,6 @@ func (c *Compiler) parseExpr(frame *Frame, expr ssa.Value) (llvm.Value, error) {
 
 		switch typ := expr.X.Type().Underlying().(type) {
 		case *types.Pointer: // pointer to array
-			if expr.Max != nil {
-				return llvm.Value{}, c.makeError(expr.Pos(), "todo: full slice expressions (with max): "+expr.Type().String())
-			}
 			// slice an array
 			length := typ.Elem().Underlying().(*types.Array).Len()
 			llvmLen := llvm.ConstInt(c.uintptrType, uint64(length), false)
diff --git a/testdata/slice.go b/testdata/slice.go
index 8c5bae41..8182af36 100644
--- a/testdata/slice.go
+++ b/testdata/slice.go
@@ -79,6 +79,19 @@ func main() {
 	assert(cap(longfoo[uint64(1):uint64(3):uint64(5)]) == 4)
 	assert(cap(longfoo[uintptr(1):uintptr(3):uintptr(5)]) == 4)
 
+	// slicing an array with max parameter (added in Go 1.2)
+	assert(cap(arr[int(1):int(2):int(4)]) == 3)
+	assert(cap(arr[int8(1):int8(2):int8(4)]) == 3)
+	assert(cap(arr[int16(1):int16(2):int16(4)]) == 3)
+	assert(cap(arr[int32(1):int32(2):int32(4)]) == 3)
+	assert(cap(arr[int64(1):int64(2):int64(4)]) == 3)
+	assert(cap(arr[uint(1):uint(2):uint(4)]) == 3)
+	assert(cap(arr[uint8(1):uint8(2):uint8(4)]) == 3)
+	assert(cap(arr[uint16(1):uint16(2):uint16(4)]) == 3)
+	assert(cap(arr[uint32(1):uint32(2):uint32(4)]) == 3)
+	assert(cap(arr[uint64(1):uint64(2):uint64(4)]) == 3)
+	assert(cap(arr[uintptr(1):uintptr(2):uintptr(4)]) == 3)
+
 	// copy
 	println("copy foo -> bar:", copy(bar, foo))
 	printslice("bar", bar)