[dev.typeparams] cmd/compile/internal/syntax: prepare syntax nodes for type parameters

- add TParamList fields to TypeDecl, FuncDecl
- also: change File.Lines to File.EOF so we have the actual file end position

Change-Id: Ia345f888080a884f7ac5cefd8bff3d80e4a59cdc
Reviewed-on: https://go-review.googlesource.com/c/go/+/261657
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

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

@@ -60,7 +60,7 @@ func parseFiles(filenames []string) uint {
 		}
 
 		p.node()
-		lines += p.file.Lines
+		lines += p.file.EOF.Line()
 		p.file = nil // release memory
 
 		if nsyntaxerrors != 0 {

src/cmd/compile/internal/syntax/nodes.go

@@ -37,7 +37,7 @@ type File struct {
 	Pragma   Pragma
 	PkgName  *Name
 	DeclList []Decl
-	Lines    uint
+	EOF      Pos
 	node
 }
 
@@ -77,6 +77,7 @@ type (
 		Group      *Group // nil means not part of a group
 		Pragma     Pragma
 		Name       *Name
+		TParamList []*Field // nil means no type parameters
 		Alias      bool
 		Type       Expr
 		decl
@@ -102,6 +103,7 @@ type (
 		Pragma     Pragma
 		Recv       *Field // nil means regular function
 		Name       *Name
+		TParamList []*Field // nil means no type parameters
 		Type       *FuncType
 		Body       *BlockStmt // nil means no body (forward declaration)
 		decl
@@ -226,6 +228,7 @@ type (
 		Fun      Expr
 		ArgList  []Expr // nil means no arguments
 		HasDots  bool   // last argument is followed by ...
+		Brackets bool   // []'s instead of ()'s
 		expr
 	}
 
@@ -272,7 +275,7 @@ type (
 
 	// interface { MethodList[0]; MethodList[1]; ... }
 	InterfaceType struct {
-		MethodList []*Field
+		MethodList []*Field // a field named "type" means a type constraint
 		expr
 	}
 

src/cmd/compile/internal/syntax/parser.go

@@ -445,7 +445,7 @@ func (p *parser) fileOrNil() *File {
 	// p.tok == _EOF
 
 	p.clearPragma()
-	f.Lines = p.line
+	f.EOF = p.pos()
 
 	return f
 }

src/cmd/compile/internal/syntax/parser_test.go

@@ -76,7 +76,7 @@ func TestStdLib(t *testing.T) {
 				if *verify {
 					verifyPrint(filename, ast)
 				}
-				results <- parseResult{filename, ast.Lines}
+				results <- parseResult{filename, ast.EOF.Line()}
 			})
 		}
 	}()