compiler: fix a few crashes due to named types

There were a few cases left where a named type would cause a crash in
the compiler. While going through enough code would have found them
eventually, I specifically looked for the `Type().(` pattern: a Type()
call that is then used in a type assert. Most of those were indeed bugs,
although for some I couldn't come up with a reproducer so I left them
as-is.

compiler/channel.go

@@ -12,7 +12,7 @@ import (
 )
 
 func (b *builder) createMakeChan(expr *ssa.MakeChan) llvm.Value {
-	elementSize := b.targetData.TypeAllocSize(b.getLLVMType(expr.Type().(*types.Chan).Elem()))
+	elementSize := b.targetData.TypeAllocSize(b.getLLVMType(expr.Type().Underlying().(*types.Chan).Elem()))
 	elementSizeValue := llvm.ConstInt(b.uintptrType, elementSize, false)
 	bufSize := b.getValue(expr.Size)
 	b.createChanBoundsCheck(elementSize, bufSize, expr.Size.Type().Underlying().(*types.Basic), expr.Pos())
@@ -47,7 +47,7 @@ func (b *builder) createChanSend(instr *ssa.Send) {
 // createChanRecv emits a pseudo chan receive operation. It is lowered to the
 // actual channel receive operation during goroutine lowering.
 func (b *builder) createChanRecv(unop *ssa.UnOp) llvm.Value {
-	valueType := b.getLLVMType(unop.X.Type().(*types.Chan).Elem())
+	valueType := b.getLLVMType(unop.X.Type().Underlying().(*types.Chan).Elem())
 	ch := b.getValue(unop.X)
 
 	// Allocate memory to receive into.
@@ -117,7 +117,7 @@ func (b *builder) createSelect(expr *ssa.Select) llvm.Value {
 		switch state.Dir {
 		case types.RecvOnly:
 			// Make sure the receive buffer is big enough and has the correct alignment.
-			llvmType := b.getLLVMType(state.Chan.Type().(*types.Chan).Elem())
+			llvmType := b.getLLVMType(state.Chan.Type().Underlying().(*types.Chan).Elem())
 			if size := b.targetData.TypeAllocSize(llvmType); size > recvbufSize {
 				recvbufSize = size
 			}

compiler/compiler.go

@@ -1053,7 +1053,7 @@ func (b *builder) createInstruction(instr ssa.Instruction) {
 			// goroutine:
 			//   * The function context, for closures.
 			//   * The function pointer (for tasks).
-			funcPtr, context := b.decodeFuncValue(b.getValue(instr.Call.Value), instr.Call.Value.Type().(*types.Signature))
+			funcPtr, context := b.decodeFuncValue(b.getValue(instr.Call.Value), instr.Call.Value.Type().Underlying().(*types.Signature))
 			params = append(params, context) // context parameter
 			switch b.Scheduler() {
 			case "none", "coroutines":
@@ -1516,7 +1516,7 @@ func (b *builder) createExpr(expr ssa.Value) (llvm.Value, error) {
 		index := b.getValue(expr.Index)
 
 		// Check bounds.
-		arrayLen := expr.X.Type().(*types.Array).Len()
+		arrayLen := expr.X.Type().Underlying().(*types.Array).Len()
 		arrayLenLLVM := llvm.ConstInt(b.uintptrType, uint64(arrayLen), false)
 		b.createLookupBoundsCheck(arrayLenLLVM, index, expr.Index.Type())
 
@@ -1628,8 +1628,8 @@ func (b *builder) createExpr(expr ssa.Value) (llvm.Value, error) {
 		}
 
 		// Bounds checking.
-		lenType := expr.Len.Type().(*types.Basic)
+		lenType := expr.Len.Type().Underlying().(*types.Basic)
-		capType := expr.Cap.Type().(*types.Basic)
+		capType := expr.Cap.Type().Underlying().(*types.Basic)
 		b.createSliceBoundsCheck(maxSize, sliceLen, sliceCap, sliceCap, lenType, capType, capType)
 
 		// Allocate the backing array.

testdata/channel.go

@@ -8,6 +8,8 @@ import (
 
 var wg sync.WaitGroup
 
+type intchan chan int
+
 func main() {
 	ch := make(chan int, 2)
 	ch <- 1
@@ -40,6 +42,15 @@ func main() {
 	_ = make(chan int, uint32(2))
 	_ = make(chan int, uint64(2))
 
+	// Test that named channels don't crash the compiler.
+	named := make(intchan, 1)
+	named <- 3
+	<-named
+	select {
+	case <-named:
+	default:
+	}
+
 	// Test bigger values
 	ch2 := make(chan complex128)
 	wg.Add(1)

testdata/coroutines.go

@@ -68,6 +68,8 @@ func main() {
 	m.Unlock()
 	println("done")
 
+	startSimpleFunc(emptyFunc)
+
 	time.Sleep(2 * time.Millisecond)
 }
 
@@ -100,6 +102,11 @@ func sleepFuncValue(fn func(int)) {
 	go fn(8)
 }
 
+func startSimpleFunc(fn simpleFunc) {
+	// Test that named function types don't crash the compiler.
+	go fn()
+}
+
 func nowait() {
 	println("non-blocking goroutine")
 }
@@ -115,3 +122,8 @@ func (i *myPrinter) Print() {
 	time.Sleep(time.Millisecond)
 	println("async interface method call")
 }
+
+type simpleFunc func()
+
+func emptyFunc() {
+}

testdata/slice.go

@@ -31,6 +31,7 @@ func main() {
 	assert(len(make([]int, makeUint32(2), makeUint32(3))) == 2)
 	assert(len(make([]int, makeUint64(2), makeUint64(3))) == 2)
 	assert(len(make([]int, makeUintptr(2), makeUintptr(3))) == 2)
+	assert(len(make([]int, makeMyUint8(2), makeMyUint8(3))) == 2)
 
 	// indexing into a slice with uncommon index types
 	assert(foo[int(2)] == 4)
@@ -131,6 +132,9 @@ func main() {
 	var named MySlice
 	assert(len(unnamed[:]) == 32)
 	assert(len(named[:]) == 32)
+	for _, c := range named {
+		assert(c == 0)
+	}
 }
 
 func printslice(name string, s []int) {
@@ -169,3 +173,4 @@ func makeUint16(x uint16) uint16    { return x }
 func makeUint32(x uint32) uint32    { return x }
 func makeUint64(x uint64) uint64    { return x }
 func makeUintptr(x uintptr) uintptr { return x }
+func makeMyUint8(x myUint8) myUint8 { return x }