all: remove some unused result params

Most of these are return values that were part of a receiving parameter,
so they're still accessible.

A few others are not, but those have never had a use.

Found with github.com/mvdan/unparam, after Kevin Burke's suggestion that
the tool should also warn about unused result parameters.

Change-Id: Id8b5ed89912a99db22027703a88bd94d0b292b8b
Reviewed-on: https://go-review.googlesource.com/55910
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/cmd/asm/internal/asm/parse.go

@@ -258,11 +258,11 @@ func (p *Parser) parseScale(s string) int8 {
 }
 
 // operand parses a general operand and stores the result in *a.
-func (p *Parser) operand(a *obj.Addr) bool {
+func (p *Parser) operand(a *obj.Addr) {
 	//fmt.Printf("Operand: %v\n", p.input)
 	if len(p.input) == 0 {
 		p.errorf("empty operand: cannot happen")
-		return false
+		return
 	}
 	// General address (with a few exceptions) looks like
 	//	$sym±offset(SB)(reg)(index*scale)
@@ -290,7 +290,7 @@ func (p *Parser) operand(a *obj.Addr) bool {
 		p.symbolReference(a, name, prefix)
 		// fmt.Printf("SYM %s\n", obj.Dconv(&emptyProg, 0, a))
 		if p.peek() == scanner.EOF {
-			return true
+			return
 		}
 	}
 
@@ -301,7 +301,7 @@ func (p *Parser) operand(a *obj.Addr) bool {
 		}
 		p.registerList(a)
 		p.expectOperandEnd()
-		return true
+		return
 	}
 
 	// Register: R1
@@ -335,7 +335,7 @@ func (p *Parser) operand(a *obj.Addr) bool {
 		}
 		// fmt.Printf("REG %s\n", obj.Dconv(&emptyProg, 0, a))
 		p.expectOperandEnd()
-		return true
+		return
 	}
 
 	// Constant.
@@ -348,7 +348,7 @@ func (p *Parser) operand(a *obj.Addr) bool {
 		tok := p.next()
 		if tok.ScanToken == scanner.EOF {
 			p.errorf("missing right parenthesis")
-			return false
+			return
 		}
 		rname := tok.String()
 		p.back()
@@ -367,12 +367,12 @@ func (p *Parser) operand(a *obj.Addr) bool {
 			a.Val = p.floatExpr()
 			// fmt.Printf("FCONST %s\n", obj.Dconv(&emptyProg, 0, a))
 			p.expectOperandEnd()
-			return true
+			return
 		}
 		if p.have(scanner.String) {
 			if prefix != '$' {
 				p.errorf("string constant must be an immediate")
-				return false
+				return
 			}
 			str, err := strconv.Unquote(p.get(scanner.String).String())
 			if err != nil {
@@ -382,7 +382,7 @@ func (p *Parser) operand(a *obj.Addr) bool {
 			a.Val = str
 			// fmt.Printf("SCONST %s\n", obj.Dconv(&emptyProg, 0, a))
 			p.expectOperandEnd()
-			return true
+			return
 		}
 		a.Offset = int64(p.expr())
 		if p.peek() != '(' {
@@ -396,7 +396,7 @@ func (p *Parser) operand(a *obj.Addr) bool {
 			}
 			// fmt.Printf("CONST %d %s\n", a.Offset, obj.Dconv(&emptyProg, 0, a))
 			p.expectOperandEnd()
-			return true
+			return
 		}
 		// fmt.Printf("offset %d \n", a.Offset)
 	}
@@ -406,7 +406,7 @@ func (p *Parser) operand(a *obj.Addr) bool {
 	// fmt.Printf("DONE %s\n", p.arch.Dconv(&emptyProg, 0, a))
 
 	p.expectOperandEnd()
-	return true
+	return
 }
 
 // atStartOfRegister reports whether the parser is at the start of a register definition.

src/cmd/compile/internal/gc/dcl.go

@@ -742,7 +742,7 @@ func tointerface(l []*Node) *types.Type {
 	return t
 }
 
-func tointerface0(t *types.Type, l []*Node) *types.Type {
+func tointerface0(t *types.Type, l []*Node) {
 	if t == nil || !t.IsInterface() {
 		Fatalf("interface expected")
 	}
@@ -756,8 +756,6 @@ func tointerface0(t *types.Type, l []*Node) *types.Type {
 		fields = append(fields, f)
 	}
 	t.SetInterface(fields)
-
-	return t
 }
 
 func fakeRecv() *Node {

src/cmd/compile/internal/gc/typecheck.go

@@ -3671,7 +3671,7 @@ ret:
 	ntypecheckdeftype--
 }
 
-func typecheckdef(n *Node) *Node {
+func typecheckdef(n *Node) {
 	lno := lineno
 	setlineno(n)
 
@@ -3687,11 +3687,11 @@ func typecheckdef(n *Node) *Node {
 			yyerror("undefined: %v", n.Sym)
 		}
 
-		return n
+		return
 	}
 
 	if n.Walkdef() == 1 {
-		return n
+		return
 	}
 
 	typecheckdefstack = append(typecheckdefstack, n)
@@ -3857,7 +3857,7 @@ ret:
 
 	lineno = lno
 	n.SetWalkdef(1)
-	return n
+	return
 }
 
 func checkmake(t *types.Type, arg string, n *Node) bool {

src/cmd/compile/internal/ssa/trim.go

@@ -121,9 +121,8 @@ func trimmableBlock(b *Block) bool {
 }
 
 // mergePhi adjusts the number of `v`s arguments to account for merge
-// of `b`, which was `i`th predecessor of the `v`s block. Returns
-// `v`.
-func mergePhi(v *Value, i int, b *Block) *Value {
+// of `b`, which was `i`th predecessor of the `v`s block.
+func mergePhi(v *Value, i int, b *Block) {
 	u := v.Args[i]
 	if u.Block == b {
 		if u.Op != OpPhi {
@@ -147,5 +146,4 @@ func mergePhi(v *Value, i int, b *Block) *Value {
 			v.AddArg(v.Args[i])
 		}
 	}
-	return v
 }

src/cmd/go/internal/load/pkg.go

@@ -857,7 +857,7 @@ var foldPath = make(map[string]string)
 
 // load populates p using information from bp, err, which should
 // be the result of calling build.Context.Import.
-func (p *Package) load(stk *ImportStack, bp *build.Package, err error) *Package {
+func (p *Package) load(stk *ImportStack, bp *build.Package, err error) {
 	p.copyBuild(bp)
 
 	// The localPrefix is the path we interpret ./ imports relative to.
@@ -874,7 +874,7 @@ func (p *Package) load(stk *ImportStack, bp *build.Package, err error) *Package
 			ImportStack: stk.Copy(),
 			Err:         err.Error(),
 		}
-		return p
+		return
 	}
 
 	useBindir := p.Name == "main"
@@ -891,7 +891,7 @@ func (p *Package) load(stk *ImportStack, bp *build.Package, err error) *Package
 			newPath := strings.Replace(p.ImportPath, "code.google.com/p/go.", "golang.org/x/", 1)
 			e := fmt.Sprintf("the %v command has moved; use %v instead.", p.ImportPath, newPath)
 			p.Error = &PackageError{Err: e}
-			return p
+			return
 		}
 		_, elem := filepath.Split(p.Dir)
 		full := cfg.BuildContext.GOOS + "_" + cfg.BuildContext.GOARCH + "/" + elem
@@ -1046,7 +1046,7 @@ func (p *Package) load(stk *ImportStack, bp *build.Package, err error) *Package
 			ImportStack: stk.Copy(),
 			Err:         fmt.Sprintf("case-insensitive file name collision: %q and %q", f1, f2),
 		}
-		return p
+		return
 	}
 
 	// Build list of imported packages and full dependency list.
@@ -1141,7 +1141,7 @@ func (p *Package) load(stk *ImportStack, bp *build.Package, err error) *Package
 			ImportStack: stk.Copy(),
 			Err:         fmt.Sprintf("C source files not allowed when not using cgo or SWIG: %s", strings.Join(p.CFiles, " ")),
 		}
-		return p
+		return
 	}
 
 	// Check for case-insensitive collisions of import paths.
@@ -1153,7 +1153,7 @@ func (p *Package) load(stk *ImportStack, bp *build.Package, err error) *Package
 			ImportStack: stk.Copy(),
 			Err:         fmt.Sprintf("case-insensitive import collision: %q and %q", p.ImportPath, other),
 		}
-		return p
+		return
 	}
 
 	if p.BinaryOnly {
@@ -1165,7 +1165,6 @@ func (p *Package) load(stk *ImportStack, bp *build.Package, err error) *Package
 	} else {
 		computeBuildID(p)
 	}
-	return p
 }
 
 // InternalDeps returns the full dependency list for p,

src/encoding/json/encode.go

@@ -871,8 +871,7 @@ func (w *reflectWithString) resolve() error {
 }
 
 // NOTE: keep in sync with stringBytes below.
-func (e *encodeState) string(s string, escapeHTML bool) int {
-	len0 := e.Len()
+func (e *encodeState) string(s string, escapeHTML bool) {
 	e.WriteByte('"')
 	start := 0
 	for i := 0; i < len(s); {
@@ -944,12 +943,10 @@ func (e *encodeState) string(s string, escapeHTML bool) int {
 		e.WriteString(s[start:])
 	}
 	e.WriteByte('"')
-	return e.Len() - len0
 }
 
 // NOTE: keep in sync with string above.
-func (e *encodeState) stringBytes(s []byte, escapeHTML bool) int {
-	len0 := e.Len()
+func (e *encodeState) stringBytes(s []byte, escapeHTML bool) {
 	e.WriteByte('"')
 	start := 0
 	for i := 0; i < len(s); {
@@ -1021,7 +1018,6 @@ func (e *encodeState) stringBytes(s []byte, escapeHTML bool) int {
 		e.Write(s[start:])
 	}
 	e.WriteByte('"')
-	return e.Len() - len0
 }
 
 // A field represents a single field found in a struct.

src/testing/benchmark.go

@@ -238,7 +238,7 @@ var labelsOnce sync.Once
 
 // run executes the benchmark in a separate goroutine, including all of its
 // subbenchmarks. b must not have subbenchmarks.
-func (b *B) run() BenchmarkResult {
+func (b *B) run() {
 	labelsOnce.Do(func() {
 		fmt.Fprintf(b.w, "goos: %s\n", runtime.GOOS)
 		fmt.Fprintf(b.w, "goarch: %s\n", runtime.GOARCH)
@@ -253,7 +253,6 @@ func (b *B) run() BenchmarkResult {
 		// Running func Benchmark.
 		b.doBench()
 	}
-	return b.result
 }
 
 func (b *B) doBench() BenchmarkResult {