go/types: spell out 'Type' in type parameter APIs

As discussed on the go/types proposal (#47916), we should spell out the
word 'Type', rather than using 'T'.

Change-Id: I5f51255eedc07fea61f909b7ecb3093a7fab765e
Reviewed-on: https://go-review.googlesource.com/c/go/+/348376
Trust: Robert Findley <rfindley@google.com>
Run-TryBot: Robert Findley <rfindley@google.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>

src/go/internal/gcimporter/iimport.go

@@ -305,7 +305,7 @@ func (r *importReader) obj(name string) {
 			tparams = r.tparamList()
 		}
 		sig := r.signature(nil)
-		sig.SetTParams(tparams)
+		sig.SetTypeParams(tparams)
 		r.declare(types.NewFunc(pos, r.currPkg, name, sig))
 
 	case 'T', 'U':
@@ -317,7 +317,7 @@ func (r *importReader) obj(name string) {
 		// declaration before recursing.
 		obj := types.NewTypeName(pos, r.currPkg, name, nil)
 		named := types.NewNamed(obj, nil, nil)
-		named.SetTParams(tparams)
+		named.SetTypeParams(tparams)
 		r.declare(obj)
 
 		underlying := r.p.typAt(r.uint64(), named).Underlying()
@@ -333,7 +333,7 @@ func (r *importReader) obj(name string) {
 				// If the receiver has any targs, set those as the
 				// rparams of the method (since those are the
 				// typeparams being used in the method sig/body).
-				targs := baseType(msig.Recv().Type()).TArgs()
+				targs := baseType(msig.Recv().Type()).TypeArgs()
 				if targs.Len() > 0 {
 					rparams := make([]*types.TypeParam, targs.Len())
 					for i := range rparams {

src/go/types/api_test.go

@@ -1851,7 +1851,7 @@ func TestInstantiate(t *testing.T) {
 
 	// type T should have one type parameter
 	T := pkg.Scope().Lookup("T").Type().(*Named)
-	if n := T.TParams().Len(); n != 1 {
+	if n := T.TypeParams().Len(); n != 1 {
 		t.Fatalf("expected 1 type parameter; found %d", n)
 	}
 

src/go/types/assignments.go

@@ -71,7 +71,7 @@ func (check *Checker) assignment(x *operand, T Type, context string) {
 	}
 
 	// A generic (non-instantiated) function value cannot be assigned to a variable.
-	if sig := asSignature(x.typ); sig != nil && sig.TParams().Len() > 0 {
+	if sig := asSignature(x.typ); sig != nil && sig.TypeParams().Len() > 0 {
 		check.errorf(x, _Todo, "cannot use generic function %s without instantiation in %s", x, context)
 	}
 

src/go/types/call.go

@@ -31,7 +31,7 @@ func (check *Checker) funcInst(x *operand, ix *typeparams.IndexExpr) {
 
 	// check number of type arguments (got) vs number of type parameters (want)
 	sig := x.typ.(*Signature)
-	got, want := len(targs), sig.TParams().Len()
+	got, want := len(targs), sig.TypeParams().Len()
 	if got > want {
 		check.errorf(ix.Indices[got-1], _Todo, "got %d type arguments but want %d", got, want)
 		x.mode = invalid
@@ -43,7 +43,7 @@ func (check *Checker) funcInst(x *operand, ix *typeparams.IndexExpr) {
 	inferred := false
 
 	if got < want {
-		targs = check.infer(ix.Orig, sig.TParams().list(), targs, nil, nil, true)
+		targs = check.infer(ix.Orig, sig.TypeParams().list(), targs, nil, nil, true)
 		if targs == nil {
 			// error was already reported
 			x.mode = invalid
@@ -65,7 +65,7 @@ func (check *Checker) funcInst(x *operand, ix *typeparams.IndexExpr) {
 
 	// instantiate function signature
 	res := check.instantiate(x.Pos(), sig, targs, poslist).(*Signature)
-	assert(res.TParams().Len() == 0) // signature is not generic anymore
+	assert(res.TypeParams().Len() == 0) // signature is not generic anymore
 	if inferred {
 		check.recordInferred(ix.Orig, targs, res)
 	}
@@ -171,7 +171,7 @@ func (check *Checker) callExpr(x *operand, call *ast.CallExpr) exprKind {
 		assert(len(targs) == len(ix.Indices))
 
 		// check number of type arguments (got) vs number of type parameters (want)
-		got, want := len(targs), sig.TParams().Len()
+		got, want := len(targs), sig.TypeParams().Len()
 		if got > want {
 			check.errorf(ix.Indices[want], _Todo, "got %d type arguments but want %d", got, want)
 			check.use(call.Args...)
@@ -205,7 +205,7 @@ func (check *Checker) callExpr(x *operand, call *ast.CallExpr) exprKind {
 
 	// if type inference failed, a parametrized result must be invalidated
 	// (operands cannot have a parametrized type)
-	if x.mode == value && sig.TParams().Len() > 0 && isParameterized(sig.TParams().list(), x.typ) {
+	if x.mode == value && sig.TypeParams().Len() > 0 && isParameterized(sig.TypeParams().list(), x.typ) {
 		x.mode = invalid
 	}
 
@@ -334,7 +334,7 @@ func (check *Checker) arguments(call *ast.CallExpr, sig *Signature, targs []Type
 	}
 
 	// infer type arguments and instantiate signature if necessary
-	if sig.TParams().Len() > 0 {
+	if sig.TypeParams().Len() > 0 {
 		if !check.allowVersion(check.pkg, 1, 18) {
 			switch call.Fun.(type) {
 			case *ast.IndexExpr, *ast.MultiIndexExpr:
@@ -346,21 +346,21 @@ func (check *Checker) arguments(call *ast.CallExpr, sig *Signature, targs []Type
 		}
 		// TODO(gri) provide position information for targs so we can feed
 		//           it to the instantiate call for better error reporting
-		targs := check.infer(call, sig.TParams().list(), targs, sigParams, args, true)
+		targs := check.infer(call, sig.TypeParams().list(), targs, sigParams, args, true)
 		if targs == nil {
 			return // error already reported
 		}
 
 		// compute result signature
 		rsig = check.instantiate(call.Pos(), sig, targs, nil).(*Signature)
-		assert(rsig.TParams().Len() == 0) // signature is not generic anymore
+		assert(rsig.TypeParams().Len() == 0) // signature is not generic anymore
 		check.recordInferred(call, targs, rsig)
 
 		// Optimization: Only if the parameter list was adjusted do we
 		// need to compute it from the adjusted list; otherwise we can
 		// simply use the result signature's parameter list.
 		if adjusted {
-			sigParams = check.subst(call.Pos(), sigParams, makeSubstMap(sig.TParams().list(), targs), nil).(*Tuple)
+			sigParams = check.subst(call.Pos(), sigParams, makeSubstMap(sig.TypeParams().list(), targs), nil).(*Tuple)
 		} else {
 			sigParams = rsig.params
 		}

src/go/types/decl.go

@@ -641,13 +641,13 @@ func (check *Checker) typeDecl(obj *TypeName, tdecl *ast.TypeSpec, def *Named) {
 	named.underlying = under(named)
 
 	// If the RHS is a type parameter, it must be from this type declaration.
-	if tpar, _ := named.underlying.(*TypeParam); tpar != nil && tparamIndex(named.TParams().list(), tpar) < 0 {
+	if tpar, _ := named.underlying.(*TypeParam); tpar != nil && tparamIndex(named.TypeParams().list(), tpar) < 0 {
 		check.errorf(tdecl.Type, _Todo, "cannot use function type parameter %s as RHS in type declaration", tpar)
 		named.underlying = Typ[Invalid]
 	}
 }
 
-func (check *Checker) collectTypeParams(list *ast.FieldList) *TParamList {
+func (check *Checker) collectTypeParams(list *ast.FieldList) *TypeParamList {
 	var tparams []*TypeParam
 	// Declare type parameters up-front, with empty interface as type bound.
 	// The scope of type parameters starts at the beginning of the type parameter

src/go/types/index.go

@@ -35,7 +35,7 @@ func (check *Checker) indexExpr(x *operand, e *typeparams.IndexExpr) (isFuncInst
 		return false
 
 	case value:
-		if sig := asSignature(x.typ); sig != nil && sig.TParams().Len() > 0 {
+		if sig := asSignature(x.typ); sig != nil && sig.TypeParams().Len() > 0 {
 			// function instantiation
 			return true
 		}

src/go/types/instantiate.go

@@ -38,9 +38,9 @@ func Instantiate(env *Environment, typ Type, targs []Type, validate bool) (Type,
 		var tparams []*TypeParam
 		switch t := typ.(type) {
 		case *Named:
-			tparams = t.TParams().list()
+			tparams = t.TypeParams().list()
 		case *Signature:
-			tparams = t.TParams().list()
+			tparams = t.TypeParams().list()
 		}
 		if i, err := (*Checker)(nil).verify(token.NoPos, tparams, targs); err != nil {
 			return inst, ArgumentError{i, err}
@@ -80,9 +80,9 @@ func (check *Checker) instantiate(pos token.Pos, typ Type, targs []Type, posList
 		var tparams []*TypeParam
 		switch t := typ.(type) {
 		case *Named:
-			tparams = t.TParams().list()
+			tparams = t.TypeParams().list()
 		case *Signature:
-			tparams = t.TParams().list()
+			tparams = t.TypeParams().list()
 		}
 		// Avoid duplicate errors; instantiate will have complained if tparams
 		// and targs do not have the same length.
@@ -127,7 +127,7 @@ func (check *Checker) instance(pos token.Pos, typ Type, targs []Type, env *Envir
 		return named
 
 	case *Signature:
-		tparams := t.TParams()
+		tparams := t.TypeParams()
 		if !check.validateTArgLen(pos, tparams.Len(), len(targs)) {
 			return Typ[Invalid]
 		}

src/go/types/lookup.go

@@ -319,10 +319,10 @@ func (check *Checker) missingMethod(V Type, T *Interface, static bool) (method,
 			// both methods must have the same number of type parameters
 			ftyp := f.typ.(*Signature)
 			mtyp := m.typ.(*Signature)
-			if ftyp.TParams().Len() != mtyp.TParams().Len() {
+			if ftyp.TypeParams().Len() != mtyp.TypeParams().Len() {
 				return m, f
 			}
-			if ftyp.TParams().Len() > 0 {
+			if ftyp.TypeParams().Len() > 0 {
 				panic("method with type parameters")
 			}
 
@@ -332,7 +332,7 @@ func (check *Checker) missingMethod(V Type, T *Interface, static bool) (method,
 			// TODO(gri) is this always correct? what about type bounds?
 			// (Alternative is to rename/subst type parameters and compare.)
 			u := newUnifier(true)
-			u.x.init(ftyp.TParams().list())
+			u.x.init(ftyp.TypeParams().list())
 			if !u.unify(ftyp, mtyp) {
 				return m, f
 			}
@@ -371,10 +371,10 @@ func (check *Checker) missingMethod(V Type, T *Interface, static bool) (method,
 		// both methods must have the same number of type parameters
 		ftyp := f.typ.(*Signature)
 		mtyp := m.typ.(*Signature)
-		if ftyp.TParams().Len() != mtyp.TParams().Len() {
+		if ftyp.TypeParams().Len() != mtyp.TypeParams().Len() {
 			return m, f
 		}
-		if ftyp.TParams().Len() > 0 {
+		if ftyp.TypeParams().Len() > 0 {
 			panic("method with type parameters")
 		}
 
@@ -385,7 +385,7 @@ func (check *Checker) missingMethod(V Type, T *Interface, static bool) (method,
 		// In order to compare the signatures, substitute the receiver
 		// type parameters of ftyp with V's instantiation type arguments.
 		// This lazily instantiates the signature of method f.
-		if Vn != nil && Vn.TParams().Len() > 0 {
+		if Vn != nil && Vn.TypeParams().Len() > 0 {
 			// Be careful: The number of type arguments may not match
 			// the number of receiver parameters. If so, an error was
 			// reported earlier but the length discrepancy is still

src/go/types/named.go

@@ -12,15 +12,15 @@ import (
 // A Named represents a named (defined) type.
 type Named struct {
 	check      *Checker
-	info       typeInfo    // for cycle detection
-	obj        *TypeName   // corresponding declared object for declared types; placeholder for instantiated types
-	orig       *Named      // original, uninstantiated type
-	fromRHS    Type        // type (on RHS of declaration) this *Named type is derived of (for cycle reporting)
-	underlying Type        // possibly a *Named during setup; never a *Named once set up completely
-	instPos    *token.Pos  // position information for lazy instantiation, or nil
-	tparams    *TParamList // type parameters, or nil
-	targs      *TypeList   // type arguments (after instantiation), or nil
-	methods    []*Func     // methods declared for this type (not the method set of this type); signatures are type-checked lazily
+	info       typeInfo       // for cycle detection
+	obj        *TypeName      // corresponding declared object for declared types; placeholder for instantiated types
+	orig       *Named         // original, uninstantiated type
+	fromRHS    Type           // type (on RHS of declaration) this *Named type is derived of (for cycle reporting)
+	underlying Type           // possibly a *Named during setup; never a *Named once set up completely
+	instPos    *token.Pos     // position information for lazy instantiation, or nil
+	tparams    *TypeParamList // type parameters, or nil
+	targs      *TypeList      // type arguments (after instantiation), or nil
+	methods    []*Func        // methods declared for this type (not the method set of this type); signatures are type-checked lazily
 
 	resolve func(*Named) ([]*TypeParam, Type, []*Func)
 	once    sync.Once
@@ -58,10 +58,10 @@ func (t *Named) load() *Named {
 		// (necessary because types2 expects the receiver type for methods
 		// on defined interface types to be the Named rather than the
 		// underlying Interface), maybe it should just handle calling
-		// SetTParams, SetUnderlying, and AddMethod instead?  Those
+		// SetTypeParams, SetUnderlying, and AddMethod instead?  Those
 		// methods would need to support reentrant calls though.  It would
 		// also make the API more future-proof towards further extensions
-		// (like SetTParams).
+		// (like SetTypeParams).
 
 		tparams, underlying, methods := t.resolve(t)
 
@@ -78,7 +78,7 @@ func (t *Named) load() *Named {
 }
 
 // newNamed is like NewNamed but with a *Checker receiver and additional orig argument.
-func (check *Checker) newNamed(obj *TypeName, orig *Named, underlying Type, tparams *TParamList, methods []*Func) *Named {
+func (check *Checker) newNamed(obj *TypeName, orig *Named, underlying Type, tparams *TypeParamList, methods []*Func) *Named {
 	typ := &Named{check: check, obj: obj, orig: orig, fromRHS: underlying, underlying: underlying, tparams: tparams, methods: methods}
 	if typ.orig == nil {
 		typ.orig = typ
@@ -119,15 +119,15 @@ func (t *Named) _Orig() *Named { return t.orig }
 // TODO(gri) Come up with a better representation and API to distinguish
 //           between parameterized instantiated and non-instantiated types.
 
-// TParams returns the type parameters of the named type t, or nil.
+// TypeParams returns the type parameters of the named type t, or nil.
 // The result is non-nil for an (originally) parameterized type even if it is instantiated.
-func (t *Named) TParams() *TParamList { return t.load().tparams }
+func (t *Named) TypeParams() *TypeParamList { return t.load().tparams }
 
-// SetTParams sets the type parameters of the named type t.
-func (t *Named) SetTParams(tparams []*TypeParam) { t.load().tparams = bindTParams(tparams) }
+// SetTypeParams sets the type parameters of the named type t.
+func (t *Named) SetTypeParams(tparams []*TypeParam) { t.load().tparams = bindTParams(tparams) }
 
-// TArgs returns the type arguments used to instantiate the named type t.
-func (t *Named) TArgs() *TypeList { return t.targs }
+// TypeArgs returns the type arguments used to instantiate the named type t.
+func (t *Named) TypeArgs() *TypeList { return t.targs }
 
 // NumMethods returns the number of explicit methods whose receiver is named type t.
 func (t *Named) NumMethods() int { return len(t.load().methods) }
@@ -245,8 +245,8 @@ func (n *Named) setUnderlying(typ Type) {
 func (n *Named) expand(env *Environment) *Named {
 	if n.instPos != nil {
 		// n must be loaded before instantiation, in order to have accurate
-		// tparams. This is done implicitly by the call to n.TParams, but making it
-		// explicit is harmless: load is idempotent.
+		// tparams. This is done implicitly by the call to n.TypeParams, but making
+		// it explicit is harmless: load is idempotent.
 		n.load()
 		var u Type
 		if n.check.validateTArgLen(*n.instPos, n.tparams.Len(), n.targs.Len()) {
@@ -268,7 +268,7 @@ func (n *Named) expand(env *Environment) *Named {
 				// shouldn't return that instance from expand.
 				env.typeForHash(h, n)
 			}
-			u = n.check.subst(*n.instPos, n.orig.underlying, makeSubstMap(n.TParams().list(), n.targs.list()), env)
+			u = n.check.subst(*n.instPos, n.orig.underlying, makeSubstMap(n.TypeParams().list(), n.targs.list()), env)
 		} else {
 			u = Typ[Invalid]
 		}

src/go/types/object.go

@@ -429,8 +429,8 @@ func writeObject(buf *bytes.Buffer, obj Object, qf Qualifier) {
 		if _, ok := typ.(*Basic); ok {
 			return
 		}
-		if named, _ := typ.(*Named); named != nil && named.TParams().Len() > 0 {
-			newTypeWriter(buf, qf).tParamList(named.TParams().list())
+		if named, _ := typ.(*Named); named != nil && named.TypeParams().Len() > 0 {
+			newTypeWriter(buf, qf).tParamList(named.TypeParams().list())
 		}
 		if tname.IsAlias() {
 			buf.WriteString(" =")

src/go/types/predicates.go

@@ -21,7 +21,7 @@ func isNamed(typ Type) bool {
 func isGeneric(typ Type) bool {
 	// A parameterized type is only instantiated if it doesn't have an instantiation already.
 	named, _ := typ.(*Named)
-	return named != nil && named.obj != nil && named.targs == nil && named.TParams() != nil
+	return named != nil && named.obj != nil && named.targs == nil && named.TypeParams() != nil
 }
 
 func is(typ Type, what BasicInfo) bool {
@@ -220,7 +220,7 @@ func identical(x, y Type, cmpTags bool, p *ifacePair) bool {
 		// parameter names.
 		if y, ok := y.(*Signature); ok {
 			return x.variadic == y.variadic &&
-				identicalTParams(x.TParams().list(), y.TParams().list(), cmpTags, p) &&
+				identicalTParams(x.TypeParams().list(), y.TypeParams().list(), cmpTags, p) &&
 				identical(x.params, y.params, cmpTags, p) &&
 				identical(x.results, y.results, cmpTags, p)
 		}
@@ -305,8 +305,8 @@ func identical(x, y Type, cmpTags bool, p *ifacePair) bool {
 			x.expand(nil)
 			y.expand(nil)
 
-			xargs := x.TArgs().list()
-			yargs := y.TArgs().list()
+			xargs := x.TypeArgs().list()
+			yargs := y.TypeArgs().list()
 
 			if len(xargs) != len(yargs) {
 				return false