all: single space after period

Done with grep & interactive search & replace, to double-check
replacements. Not many remained after CL 20022.

Fixes #18572

Change-Id: Idbe90ba3b584f9b9661d2bbd141607daaadfa41a
Reviewed-on: https://go-review.googlesource.com/45270
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>

src/bufio/bufio.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Package bufio implements buffered I/O.  It wraps an io.Reader or io.Writer
+// Package bufio implements buffered I/O. It wraps an io.Reader or io.Writer
 // object, creating another object (Reader or Writer) that also implements
 // the interface but provides buffering and some help for textual I/O.
 package bufio

src/cmd/cgo/doc.go

@@ -14,27 +14,27 @@ as C.stdout, or functions such as C.putchar.
 
 If the import of "C" is immediately preceded by a comment, that
 comment, called the preamble, is used as a header when compiling
-the C parts of the package.  For example:
+the C parts of the package. For example:
 
 	// #include <stdio.h>
 	// #include <errno.h>
 	import "C"
 
 The preamble may contain any C code, including function and variable
-declarations and definitions.  These may then be referred to from Go
-code as though they were defined in the package "C".  All names
+declarations and definitions. These may then be referred to from Go
+code as though they were defined in the package "C". All names
 declared in the preamble may be used, even if they start with a
-lower-case letter.  Exception: static variables in the preamble may
+lower-case letter. Exception: static variables in the preamble may
 not be referenced from Go code; static functions are permitted.
 
-See $GOROOT/misc/cgo/stdio and $GOROOT/misc/cgo/gmp for examples.  See
+See $GOROOT/misc/cgo/stdio and $GOROOT/misc/cgo/gmp for examples. See
 "C? Go? Cgo!" for an introduction to using cgo:
 https://golang.org/doc/articles/c_go_cgo.html.
 
 CFLAGS, CPPFLAGS, CXXFLAGS, FFLAGS and LDFLAGS may be defined with pseudo
 #cgo directives within these comments to tweak the behavior of the C, C++
-or Fortran compiler.  Values defined in multiple directives are concatenated
-together.  The directive can include a list of build constraints limiting its
+or Fortran compiler. Values defined in multiple directives are concatenated
+together. The directive can include a list of build constraints limiting its
 effect to systems satisfying one of the constraints
 (see https://golang.org/pkg/go/build/#hdr-Build_Constraints for details about the constraint syntax).
 For example:
@@ -57,16 +57,16 @@ The default pkg-config tool may be changed by setting the PKG_CONFIG environment
 
 When building, the CGO_CFLAGS, CGO_CPPFLAGS, CGO_CXXFLAGS, CGO_FFLAGS and
 CGO_LDFLAGS environment variables are added to the flags derived from
-these directives.  Package-specific flags should be set using the
+these directives. Package-specific flags should be set using the
 directives, not the environment variables, so that builds work in
 unmodified environments.
 
 All the cgo CPPFLAGS and CFLAGS directives in a package are concatenated and
-used to compile C files in that package.  All the CPPFLAGS and CXXFLAGS
+used to compile C files in that package. All the CPPFLAGS and CXXFLAGS
 directives in a package are concatenated and used to compile C++ files in that
-package.  All the CPPFLAGS and FFLAGS directives in a package are concatenated
-and used to compile Fortran files in that package.  All the LDFLAGS directives
-in any package in the program are concatenated and used at link time.  All the
+package. All the CPPFLAGS and FFLAGS directives in a package are concatenated
+and used to compile Fortran files in that package. All the LDFLAGS directives
+in any package in the program are concatenated and used at link time. All the
 pkg-config directives are concatenated and sent to pkg-config simultaneously
 to add to each appropriate set of command-line flags.
 
@@ -84,27 +84,27 @@ Will be expanded to:
 
 When the Go tool sees that one or more Go files use the special import
 "C", it will look for other non-Go files in the directory and compile
-them as part of the Go package.  Any .c, .s, or .S files will be
-compiled with the C compiler.  Any .cc, .cpp, or .cxx files will be
-compiled with the C++ compiler.  Any .f, .F, .for or .f90 files will be
+them as part of the Go package. Any .c, .s, or .S files will be
+compiled with the C compiler. Any .cc, .cpp, or .cxx files will be
+compiled with the C++ compiler. Any .f, .F, .for or .f90 files will be
 compiled with the fortran compiler. Any .h, .hh, .hpp, or .hxx files will
 not be compiled separately, but, if these header files are changed,
-the C and C++ files will be recompiled.  The default C and C++
+the C and C++ files will be recompiled. The default C and C++
 compilers may be changed by the CC and CXX environment variables,
 respectively; those environment variables may include command line
 options.
 
 The cgo tool is enabled by default for native builds on systems where
-it is expected to work.  It is disabled by default when
-cross-compiling.  You can control this by setting the CGO_ENABLED
+it is expected to work. It is disabled by default when
+cross-compiling. You can control this by setting the CGO_ENABLED
 environment variable when running the go tool: set it to 1 to enable
-the use of cgo, and to 0 to disable it.  The go tool will set the
+the use of cgo, and to 0 to disable it. The go tool will set the
 build constraint "cgo" if cgo is enabled.
 
 When cross-compiling, you must specify a C cross-compiler for cgo to
-use.  You can do this by setting the CC_FOR_TARGET environment
+use. You can do this by setting the CC_FOR_TARGET environment
 variable when building the toolchain using make.bash, or by setting
-the CC environment variable any time you run the go tool.  The
+the CC environment variable any time you run the go tool. The
 CXX_FOR_TARGET and CXX environment variables work in a similar way for
 C++ code.
 
@@ -138,7 +138,7 @@ C's union types are represented as a Go byte array with the same length.
 Go structs cannot embed fields with C types.
 
 Go code cannot refer to zero-sized fields that occur at the end of
-non-empty C structs.  To get the address of such a field (which is the
+non-empty C structs. To get the address of such a field (which is the
 only operation you can do with a zero-sized field) you must take the
 address of the struct and add the size of the struct.
 
@@ -150,7 +150,7 @@ is different from the same C type used in another.
 Any C function (even void functions) may be called in a multiple
 assignment context to retrieve both the return value (if any) and the
 C errno variable as an error (use _ to skip the result value if the
-function returns void).  For example:
+function returns void). For example:
 
 	n, err = C.sqrt(-1)
 	_, err := C.voidFunc()
@@ -187,11 +187,11 @@ received from Go. For example:
 In C, a function argument written as a fixed size array
 actually requires a pointer to the first element of the array.
 C compilers are aware of this calling convention and adjust
-the call accordingly, but Go cannot.  In Go, you must pass
+the call accordingly, but Go cannot. In Go, you must pass
 the pointer to the first element explicitly: C.f(&C.x[0]).
 
 A few special functions convert between Go and C types
-by making copies of the data.  In pseudo-Go definitions:
+by making copies of the data. In pseudo-Go definitions:
 
 	// Go string to C string
 	// The C string is allocated in the C heap using malloc.
@@ -253,50 +253,50 @@ must be placed in preambles in other files, or in C source files.
 Passing pointers
 
 Go is a garbage collected language, and the garbage collector needs to
-know the location of every pointer to Go memory.  Because of this,
+know the location of every pointer to Go memory. Because of this,
 there are restrictions on passing pointers between Go and C.
 
 In this section the term Go pointer means a pointer to memory
 allocated by Go (such as by using the & operator or calling the
 predefined new function) and the term C pointer means a pointer to
-memory allocated by C (such as by a call to C.malloc).  Whether a
+memory allocated by C (such as by a call to C.malloc). Whether a
 pointer is a Go pointer or a C pointer is a dynamic property
 determined by how the memory was allocated; it has nothing to do with
 the type of the pointer.
 
 Go code may pass a Go pointer to C provided the Go memory to which it
-points does not contain any Go pointers.  The C code must preserve
+points does not contain any Go pointers. The C code must preserve
 this property: it must not store any Go pointers in Go memory, even
-temporarily.  When passing a pointer to a field in a struct, the Go
+temporarily. When passing a pointer to a field in a struct, the Go
 memory in question is the memory occupied by the field, not the entire
-struct.  When passing a pointer to an element in an array or slice,
+struct. When passing a pointer to an element in an array or slice,
 the Go memory in question is the entire array or the entire backing
 array of the slice.
 
 C code may not keep a copy of a Go pointer after the call returns.
 
-A Go function called by C code may not return a Go pointer.  A Go
+A Go function called by C code may not return a Go pointer. A Go
 function called by C code may take C pointers as arguments, and it may
 store non-pointer or C pointer data through those pointers, but it may
-not store a Go pointer in memory pointed to by a C pointer.  A Go
+not store a Go pointer in memory pointed to by a C pointer. A Go
 function called by C code may take a Go pointer as an argument, but it
 must preserve the property that the Go memory to which it points does
 not contain any Go pointers.
 
-Go code may not store a Go pointer in C memory.  C code may store Go
+Go code may not store a Go pointer in C memory. C code may store Go
 pointers in C memory, subject to the rule above: it must stop storing
 the Go pointer when the C function returns.
 
-These rules are checked dynamically at runtime.  The checking is
+These rules are checked dynamically at runtime. The checking is
 controlled by the cgocheck setting of the GODEBUG environment
-variable.  The default setting is GODEBUG=cgocheck=1, which implements
-reasonably cheap dynamic checks.  These checks may be disabled
-entirely using GODEBUG=cgocheck=0.  Complete checking of pointer
+variable. The default setting is GODEBUG=cgocheck=1, which implements
+reasonably cheap dynamic checks. These checks may be disabled
+entirely using GODEBUG=cgocheck=0. Complete checking of pointer
 handling, at some cost in run time, is available via GODEBUG=cgocheck=2.
 
 It is possible to defeat this enforcement by using the unsafe package,
 and of course there is nothing stopping the C code from doing anything
-it likes.  However, programs that break these rules are likely to fail
+it likes. However, programs that break these rules are likely to fail
 in unexpected and unpredictable ways.
 
 Using cgo directly
@@ -499,7 +499,7 @@ Here is a _cgo_gotypes.go containing definitions for needed C types:
 	type _Ctype_void [0]byte
 
 The _cgo_gotypes.go file also contains the definitions of the
-functions.  They all have similar bodies that invoke runtime·cgocall
+functions. They all have similar bodies that invoke runtime·cgocall
 to make a switch from the Go runtime world to the system C (GCC-based)
 world.
 
@@ -835,7 +835,7 @@ to avoid conflicts), write the go.o file to that directory, and invoke
 the host linker. The default value for the host linker is $CC, split
 into fields, or else "gcc". The specific host linker command line can
 be overridden using command line flags: cmd/link -extld=clang
--extldflags='-ggdb -O3'.  If any package in a build includes a .cc or
+-extldflags='-ggdb -O3'. If any package in a build includes a .cc or
 other file compiled by the C++ compiler, the go tool will use the
 -extld option to set the host linker to the C++ compiler.
 

src/cmd/go/alldocs.go

@@ -118,8 +118,8 @@
 // 		a suffix to use in the name of the package installation directory,
 // 		in order to keep output separate from default builds.
 // 		If using the -race flag, the install suffix is automatically set to race
-// 		or, if set explicitly, has _race appended to it.  Likewise for the -msan
-// 		flag.  Using a -buildmode option that requires non-default compile flags
+// 		or, if set explicitly, has _race appended to it. Likewise for the -msan
+// 		flag. Using a -buildmode option that requires non-default compile flags
 // 		has a similar effect.
 // 	-ldflags 'flag list'
 // 		arguments to pass on each go tool link invocation.
@@ -243,7 +243,7 @@
 //
 // For packages, the order of scanning is determined lexically in breadth-first order.
 // That is, the package presented is the one that matches the search and is nearest
-// the root and lexically first at its level of the hierarchy.  The GOROOT tree is
+// the root and lexically first at its level of the hierarchy. The GOROOT tree is
 // always scanned in its entirety before GOPATH.
 //
 // If there is no package specified or matched, the package in the current
@@ -321,8 +321,8 @@
 // Env prints Go environment information.
 //
 // By default env prints information as a shell script
-// (on Windows, a batch file).  If one or more variable
-// names is given as arguments,  env prints the value of
+// (on Windows, a batch file). If one or more variable
+// names is given as arguments, env prints the value of
 // each named variable on its own line.
 //
 // The -json flag prints the environment in JSON format
@@ -362,7 +362,7 @@
 // 	go fmt [-n] [-x] [packages]
 //
 // Fmt runs the command 'gofmt -l -w' on the packages named
-// by the import paths.  It prints the names of the files that are modified.
+// by the import paths. It prints the names of the files that are modified.
 //
 // For more about gofmt, see 'go doc cmd/gofmt'.
 // For more about specifying packages, see 'go help packages'.
@@ -432,7 +432,7 @@
 // As a last step before running the command, any invocations of any
 // environment variables with alphanumeric names, such as $GOFILE or
 // $HOME, are expanded throughout the command line. The syntax for
-// variable expansion is $NAME on all operating systems.  Due to the
+// variable expansion is $NAME on all operating systems. Due to the
 // order of evaluation, variables are expanded even inside quoted
 // strings. If the variable NAME is not set, $NAME expands to the
 // empty string.
@@ -509,7 +509,7 @@
 // the tests for the specified packages.
 //
 // The -u flag instructs get to use the network to update the named packages
-// and their dependencies.  By default, get uses the network to check out
+// and their dependencies. By default, get uses the network to check out
 // missing packages but does not use it to look for updates to existing packages.
 //
 // The -v flag enables verbose progress and debug output.
@@ -570,7 +570,7 @@
 //     golang.org/x/net/html
 //
 // The -f flag specifies an alternate format for the list, using the
-// syntax of package template.  The default output is equivalent to -f
+// syntax of package template. The default output is equivalent to -f
 // '{{.ImportPath}}'. The struct being passed to the template is:
 //
 //     type Package struct {
@@ -663,12 +663,12 @@
 // instead of using the template format.
 //
 // The -e flag changes the handling of erroneous packages, those that
-// cannot be found or are malformed.  By default, the list command
+// cannot be found or are malformed. By default, the list command
 // prints an error to standard error for each erroneous package and
 // omits the packages from consideration during the usual printing.
 // With the -e flag, the list command never prints errors to standard
 // error and instead processes the erroneous packages with the usual
-// printing.  Erroneous packages will have a non-empty ImportPath and
+// printing. Erroneous packages will have a non-empty ImportPath and
 // a non-nil Error field; other information may or may not be missing
 // (zeroed).
 //
@@ -721,7 +721,7 @@
 // the file pattern "*_test.go".
 // Files whose names begin with "_" (including "_test.go") or "." are ignored.
 // These additional files can contain test functions, benchmark functions, and
-// example functions.  See 'go help testfunc' for more.
+// example functions. See 'go help testfunc' for more.
 // Each listed package causes the execution of a separate test binary.
 //
 // Test files that declare a package with the suffix "_test" will be compiled as a
@@ -730,7 +730,7 @@
 // The go tool will ignore a directory named "testdata", making it available
 // to hold ancillary data needed by the tests.
 //
-// By default, go test needs no arguments.  It compiles and tests the package
+// By default, go test needs no arguments. It compiles and tests the package
 // with source in the current directory, including tests, and runs the tests.
 //
 // The package is built in a temporary directory so it does not interfere with the
@@ -817,18 +817,18 @@
 //
 // There are two different ways to call between Go and C/C++ code.
 //
-// The first is the cgo tool, which is part of the Go distribution.  For
+// The first is the cgo tool, which is part of the Go distribution. For
 // information on how to use it see the cgo documentation (go doc cmd/cgo).
 //
 // The second is the SWIG program, which is a general tool for
-// interfacing between languages.  For information on SWIG see
-// http://swig.org/.  When running go build, any file with a .swig
-// extension will be passed to SWIG.  Any file with a .swigcxx extension
+// interfacing between languages. For information on SWIG see
+// http://swig.org/. When running go build, any file with a .swig
+// extension will be passed to SWIG. Any file with a .swigcxx extension
 // will be passed to SWIG with the -c++ option.
 //
 // When either cgo or SWIG is used, go build will pass any .c, .m, .s,
 // or .S files to the C compiler, and any .cc, .cpp, .cxx files to the C++
-// compiler.  The CC or CXX environment variables may be set to determine
+// compiler. The CC or CXX environment variables may be set to determine
 // the C or C++ compiler, respectively, to use.
 //
 //
@@ -941,7 +941,7 @@
 //
 // Each directory listed in GOPATH must have a prescribed structure:
 //
-// The src directory holds source code.  The path below src
+// The src directory holds source code. The path below src
 // determines the import path or executable name.
 //
 // The pkg directory holds installed package objects.
@@ -955,11 +955,11 @@
 //
 // The bin directory holds compiled commands.
 // Each command is named for its source directory, but only
-// the final element, not the entire path.  That is, the
+// the final element, not the entire path. That is, the
 // command with source in DIR/src/foo/quux is installed into
-// DIR/bin/quux, not DIR/bin/foo/quux.  The "foo/" prefix is stripped
+// DIR/bin/quux, not DIR/bin/foo/quux. The "foo/" prefix is stripped
 // so that you can add DIR/bin to your PATH to get at the
-// installed commands.  If the GOBIN environment variable is
+// installed commands. If the GOBIN environment variable is
 // set, commands are installed to the directory it names instead
 // of DIR/bin. GOBIN must be an absolute path.
 //
@@ -1102,7 +1102,7 @@
 // 	CC
 // 		The command to use to compile C code.
 // 	CGO_ENABLED
-// 		Whether the cgo command is supported.  Either 0 or 1.
+// 		Whether the cgo command is supported. Either 0 or 1.
 // 	CGO_CFLAGS
 // 		Flags that cgo will pass to the compiler when compiling
 // 		C code.
@@ -1151,7 +1151,7 @@
 // Import path syntax
 //
 // An import path (see 'go help packages') denotes a package stored in the local
-// file system.  In general, an import path denotes either a standard package (such
+// file system. In general, an import path denotes either a standard package (such
 // as "unicode/utf8") or a package found in one of the work spaces (For more
 // details see: 'go help gopath').
 //
@@ -1222,7 +1222,7 @@
 //
 // specifies the given repository, with or without the .vcs suffix,
 // using the named version control system, and then the path inside
-// that repository.  The supported version control systems are:
+// that repository. The supported version control systems are:
 //
 // 	Bazaar      .bzr
 // 	Git         .git
@@ -1242,7 +1242,7 @@
 // example.org/repo or repo.git.
 //
 // When a version control system supports multiple protocols,
-// each is tried in turn when downloading.  For example, a Git
+// each is tried in turn when downloading. For example, a Git
 // download tries https://, then git+ssh://.
 //
 // By default, downloads are restricted to known secure protocols
@@ -1360,7 +1360,7 @@
 //
 // An import path is a pattern if it includes one or more "..." wildcards,
 // each of which can match any string, including the empty string and
-// strings containing slashes.  Such a pattern expands to all package
+// strings containing slashes. Such a pattern expands to all package
 // directories found in the GOPATH trees with names matching the
 // patterns.
 //
@@ -1377,11 +1377,11 @@
 // See golang.org/s/go15vendor for more about vendoring.
 //
 // An import path can also name a package to be downloaded from
-// a remote repository.  Run 'go help importpath' for details.
+// a remote repository. Run 'go help importpath' for details.
 //
 // Every package in a program must have a unique import path.
 // By convention, this is arranged by starting each path with a
-// unique prefix that belongs to you.  For example, paths used
+// unique prefix that belongs to you. For example, paths used
 // internally at Google all begin with 'google', and paths
 // denoting remote repositories begin with the path to the code,
 // such as 'github.com/user/repo'.
@@ -1410,7 +1410,7 @@
 //
 // Several of the flags control profiling and write an execution profile
 // suitable for "go tool pprof"; run "go tool pprof -h" for more
-// information.  The --alloc_space, --alloc_objects, and --show_bytes
+// information. The --alloc_space, --alloc_objects, and --show_bytes
 // options of pprof control how the information is presented.
 //
 // The following flags are recognized by the 'go test' command and
@@ -1460,7 +1460,7 @@
 //
 // 	-cpu 1,2,4
 // 	    Specify a list of GOMAXPROCS values for which the tests or
-// 	    benchmarks should be executed.  The default is the current value
+// 	    benchmarks should be executed. The default is the current value
 // 	    of GOMAXPROCS.
 //
 // 	-list regexp
@@ -1513,7 +1513,7 @@
 // 	    calling runtime.SetBlockProfileRate with n.
 // 	    See 'go doc runtime.SetBlockProfileRate'.
 // 	    The profiler aims to sample, on average, one blocking event every
-// 	    n nanoseconds the program spends blocked.  By default,
+// 	    n nanoseconds the program spends blocked. By default,
 // 	    if -test.blockprofile is set without this flag, all blocking events
 // 	    are recorded, equivalent to -test.blockprofilerate=1.
 //
@@ -1531,7 +1531,7 @@
 //
 // 	-memprofilerate n
 // 	    Enable more precise (and expensive) memory profiles by setting
-// 	    runtime.MemProfileRate.  See 'go doc runtime.MemProfileRate'.
+// 	    runtime.MemProfileRate. See 'go doc runtime.MemProfileRate'.
 // 	    To profile all memory allocations, use -test.memprofilerate=1
 // 	    and pass --alloc_space flag to the pprof tool.
 //
@@ -1634,8 +1634,8 @@
 // "Output:" is compiled, executed, and expected to produce no output.
 //
 // Godoc displays the body of ExampleXXX to demonstrate the use
-// of the function, constant, or variable XXX.  An example of a method M with
-// receiver type T or *T is named ExampleT_M.  There may be multiple examples
+// of the function, constant, or variable XXX. An example of a method M with
+// receiver type T or *T is named ExampleT_M. There may be multiple examples
 // for a given function, constant, or variable, distinguished by a trailing _xxx,
 // where xxx is a suffix not beginning with an upper case letter.
 //

src/cmd/go/go_test.go

@@ -133,7 +133,7 @@ func TestMain(m *testing.M) {
 	if home, ccacheDir := os.Getenv("HOME"), os.Getenv("CCACHE_DIR"); home != "" && ccacheDir == "" {
 		// On some systems the default C compiler is ccache.
 		// Setting HOME to a non-existent directory will break
-		// those systems.  Set CCACHE_DIR to cope.  Issue 17668.
+		// those systems. Set CCACHE_DIR to cope. Issue 17668.
 		os.Setenv("CCACHE_DIR", filepath.Join(home, ".ccache"))
 	}
 	os.Setenv("HOME", "/test-go-home-does-not-exist")
@@ -402,7 +402,7 @@ func (tg *testgoData) doGrepMatch(match string, b *bytes.Buffer) bool {
 
 // doGrep looks for a regular expression in a buffer and fails if it
 // is not found. The name argument is the name of the output we are
-// searching, "output" or "error".  The msg argument is logged on
+// searching, "output" or "error". The msg argument is logged on
 // failure.
 func (tg *testgoData) doGrep(match string, b *bytes.Buffer, name, msg string) {
 	if !tg.doGrepMatch(match, b) {
@@ -1783,7 +1783,7 @@ func TestDefaultGOPATHPrintedSearchList(t *testing.T) {
 	tg.grepStderr(regexp.QuoteMeta(tg.path("home/go/src/github.com/golang/example/hello"))+`.*from \$GOPATH`, "expected default GOPATH")
 }
 
-// Issue 4186.  go get cannot be used to download packages to $GOROOT.
+// Issue 4186. go get cannot be used to download packages to $GOROOT.
 // Test that without GOPATH set, go get should fail.
 func TestGoGetIntoGOROOT(t *testing.T) {
 	testenv.MustHaveExternalNetwork(t)

src/cmd/go/internal/doc/doc.go

@@ -48,7 +48,7 @@ letter it is assumed to identify a symbol or method in the current directory.
 
 For packages, the order of scanning is determined lexically in breadth-first order.
 That is, the package presented is the one that matches the search and is nearest
-the root and lexically first at its level of the hierarchy.  The GOROOT tree is
+the root and lexically first at its level of the hierarchy. The GOROOT tree is
 always scanned in its entirety before GOPATH.
 
 If there is no package specified or matched, the package in the current

src/cmd/go/internal/envcmd/env.go

@@ -25,8 +25,8 @@ var CmdEnv = &base.Command{
 Env prints Go environment information.
 
 By default env prints information as a shell script
-(on Windows, a batch file).  If one or more variable
-names is given as arguments,  env prints the value of
+(on Windows, a batch file). If one or more variable
+names is given as arguments, env prints the value of
 each named variable on its own line.
 
 The -json flag prints the environment in JSON format

src/cmd/go/internal/fmtcmd/fmt.go

@@ -25,7 +25,7 @@ var CmdFmt = &base.Command{
 	Short:     "run gofmt on package sources",
 	Long: `
 Fmt runs the command 'gofmt -l -w' on the packages named
-by the import paths.  It prints the names of the files that are modified.
+by the import paths. It prints the names of the files that are modified.
 
 For more about gofmt, see 'go doc cmd/gofmt'.
 For more about specifying packages, see 'go help packages'.

src/cmd/go/internal/generate/generate.go

@@ -80,7 +80,7 @@ line.
 As a last step before running the command, any invocations of any
 environment variables with alphanumeric names, such as $GOFILE or
 $HOME, are expanded throughout the command line. The syntax for
-variable expansion is $NAME on all operating systems.  Due to the
+variable expansion is $NAME on all operating systems. Due to the
 order of evaluation, variables are expanded even inside quoted
 strings. If the variable NAME is not set, $NAME expands to the
 empty string.

src/cmd/go/internal/get/get.go

@@ -46,7 +46,7 @@ The -t flag instructs get to also download the packages required to build
 the tests for the specified packages.
 
 The -u flag instructs get to use the network to update the named packages
-and their dependencies.  By default, get uses the network to check out
+and their dependencies. By default, get uses the network to check out
 missing packages but does not use it to look for updates to existing packages.
 
 The -v flag enables verbose progress and debug output.
@@ -121,7 +121,7 @@ func runGet(cmd *base.Command, args []string) {
 		os.Setenv("GIT_SSH_COMMAND", "ssh -o ControlMaster=no")
 	}
 
-	// Phase 1.  Download/update.
+	// Phase 1. Download/update.
 	var stk load.ImportStack
 	mode := 0
 	if *getT {
@@ -151,7 +151,7 @@ func runGet(cmd *base.Command, args []string) {
 	args = load.ImportPaths(args)
 	load.PackagesForBuild(args)
 
-	// Phase 3.  Install.
+	// Phase 3. Install.
 	if *getD {
 		// Download only.
 		// Check delayed until now so that importPaths
@@ -514,7 +514,7 @@ func downloadPackage(p *load.Package) error {
 // Version "weekly.YYYY-MM-DD" matches tags like "go.weekly.YYYY-MM-DD".
 //
 // NOTE(rsc): Eventually we will need to decide on some logic here.
-// For now, there is only "go1".  This matches the docs in go help get.
+// For now, there is only "go1". This matches the docs in go help get.
 func selectTag(goVersion string, tags []string) (match string) {
 	for _, t := range tags {
 		if t == "go1" {

src/cmd/go/internal/get/vcs.go

@@ -324,7 +324,7 @@ func (v *vcsCmd) String() string {
 }
 
 // run runs the command line cmd in the given directory.
-// keyval is a list of key, value pairs.  run expands
+// keyval is a list of key, value pairs. run expands
 // instances of {key} in cmd into value, but only after
 // splitting cmd into individual arguments.
 // If an error occurs, run prints the command line and the
@@ -688,7 +688,7 @@ func repoRootForImportDynamic(importPath string, security web.SecurityMode) (*re
 	// prefix was "uni.edu" and the RepoRoot was "evilroot.com",
 	// make sure we don't trust Bob and check out evilroot.com to
 	// "uni.edu" yet (possibly overwriting/preempting another
-	// non-evil student).  Instead, first verify the root and see
+	// non-evil student). Instead, first verify the root and see
 	// if it matches Bob's claim.
 	if mmi.Prefix != importPath {
 		if cfg.BuildV {

src/cmd/go/internal/help/help.go

@@ -58,7 +58,7 @@ func Help(args []string) {
 		}
 	}
 
-	fmt.Fprintf(os.Stderr, "Unknown help topic %#q.  Run 'go help'.\n", arg)
+	fmt.Fprintf(os.Stderr, "Unknown help topic %#q. Run 'go help'.\n", arg)
 	os.Exit(2) // failed at 'go help cmd'
 }
 

src/cmd/go/internal/help/helpdoc.go

@@ -12,18 +12,18 @@ var HelpC = &base.Command{
 	Long: `
 There are two different ways to call between Go and C/C++ code.
 
-The first is the cgo tool, which is part of the Go distribution.  For
+The first is the cgo tool, which is part of the Go distribution. For
 information on how to use it see the cgo documentation (go doc cmd/cgo).
 
 The second is the SWIG program, which is a general tool for
-interfacing between languages.  For information on SWIG see
-http://swig.org/.  When running go build, any file with a .swig
-extension will be passed to SWIG.  Any file with a .swigcxx extension
+interfacing between languages. For information on SWIG see
+http://swig.org/. When running go build, any file with a .swig
+extension will be passed to SWIG. Any file with a .swigcxx extension
 will be passed to SWIG with the -c++ option.
 
 When either cgo or SWIG is used, go build will pass any .c, .m, .s,
 or .S files to the C compiler, and any .cc, .cpp, .cxx files to the C++
-compiler.  The CC or CXX environment variables may be set to determine
+compiler. The CC or CXX environment variables may be set to determine
 the C or C++ compiler, respectively, to use.
 	`,
 }
@@ -69,7 +69,7 @@ the Go repository.
 
 An import path is a pattern if it includes one or more "..." wildcards,
 each of which can match any string, including the empty string and
-strings containing slashes.  Such a pattern expands to all package
+strings containing slashes. Such a pattern expands to all package
 directories found in the GOPATH trees with names matching the
 patterns.
 
@@ -86,11 +86,11 @@ and the pattern cmd/... matches it.
 See golang.org/s/go15vendor for more about vendoring.
 
 An import path can also name a package to be downloaded from
-a remote repository.  Run 'go help importpath' for details.
+a remote repository. Run 'go help importpath' for details.
 
 Every package in a program must have a unique import path.
 By convention, this is arranged by starting each path with a
-unique prefix that belongs to you.  For example, paths used
+unique prefix that belongs to you. For example, paths used
 internally at Google all begin with 'google', and paths
 denoting remote repositories begin with the path to the code,
 such as 'github.com/user/repo'.
@@ -119,7 +119,7 @@ var HelpImportPath = &base.Command{
 	Long: `
 
 An import path (see 'go help packages') denotes a package stored in the local
-file system.  In general, an import path denotes either a standard package (such
+file system. In general, an import path denotes either a standard package (such
 as "unicode/utf8") or a package found in one of the work spaces (For more
 details see: 'go help gopath').
 
@@ -190,7 +190,7 @@ To declare the code location, an import path of the form
 
 specifies the given repository, with or without the .vcs suffix,
 using the named version control system, and then the path inside
-that repository.  The supported version control systems are:
+that repository. The supported version control systems are:
 
 	Bazaar      .bzr
 	Git         .git
@@ -210,7 +210,7 @@ denotes the foo/bar directory of the Git repository at
 example.org/repo or repo.git.
 
 When a version control system supports multiple protocols,
-each is tried in turn when downloading.  For example, a Git
+each is tried in turn when downloading. For example, a Git
 download tries https://, then git+ssh://.
 
 By default, downloads are restricted to known secure protocols
@@ -312,7 +312,7 @@ See https://golang.org/wiki/SettingGOPATH to set a custom GOPATH.
 
 Each directory listed in GOPATH must have a prescribed structure:
 
-The src directory holds source code.  The path below src
+The src directory holds source code. The path below src
 determines the import path or executable name.
 
 The pkg directory holds installed package objects.
@@ -326,11 +326,11 @@ has its compiled form installed to "DIR/pkg/GOOS_GOARCH/foo/bar.a".
 
 The bin directory holds compiled commands.
 Each command is named for its source directory, but only
-the final element, not the entire path.  That is, the
+the final element, not the entire path. That is, the
 command with source in DIR/src/foo/quux is installed into
-DIR/bin/quux, not DIR/bin/foo/quux.  The "foo/" prefix is stripped
+DIR/bin/quux, not DIR/bin/foo/quux. The "foo/" prefix is stripped
 so that you can add DIR/bin to your PATH to get at the
-installed commands.  If the GOBIN environment variable is
+installed commands. If the GOBIN environment variable is
 set, commands are installed to the directory it names instead
 of DIR/bin. GOBIN must be an absolute path.
 
@@ -477,7 +477,7 @@ Environment variables for use with cgo:
 	CC
 		The command to use to compile C code.
 	CGO_ENABLED
-		Whether the cgo command is supported.  Either 0 or 1.
+		Whether the cgo command is supported. Either 0 or 1.
 	CGO_CFLAGS
 		Flags that cgo will pass to the compiler when compiling
 		C code.

src/cmd/go/internal/list/list.go

@@ -33,7 +33,7 @@ The default output shows the package import path:
     golang.org/x/net/html
 
 The -f flag specifies an alternate format for the list, using the
-syntax of package template.  The default output is equivalent to -f
+syntax of package template. The default output is equivalent to -f
 '{{.ImportPath}}'. The struct being passed to the template is:
 
     type Package struct {
@@ -126,12 +126,12 @@ The -json flag causes the package data to be printed in JSON format
 instead of using the template format.
 
 The -e flag changes the handling of erroneous packages, those that
-cannot be found or are malformed.  By default, the list command
+cannot be found or are malformed. By default, the list command
 prints an error to standard error for each erroneous package and
 omits the packages from consideration during the usual printing.
 With the -e flag, the list command never prints errors to standard
 error and instead processes the erroneous packages with the usual
-printing.  Erroneous packages will have a non-empty ImportPath and
+printing. Erroneous packages will have a non-empty ImportPath and
 a non-nil Error field; other information may or may not be missing
 (zeroed).
 

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

@@ -343,7 +343,7 @@ const (
 
 // loadImport scans the directory named by path, which must be an import path,
 // but possibly a local import path (an absolute file system path or one beginning
-// with ./ or ../).  A local relative path is interpreted relative to srcDir.
+// with ./ or ../). A local relative path is interpreted relative to srcDir.
 // It returns a *Package describing the package found in that directory.
 func LoadImport(path, srcDir string, parent *Package, stk *ImportStack, importPos []token.Position, mode int) *Package {
 	stk.Push(path)
@@ -1747,7 +1747,7 @@ func LoadPackage(arg string, stk *ImportStack) *Package {
 }
 
 // packages returns the packages named by the
-// command line arguments 'args'.  If a named package
+// command line arguments 'args'. If a named package
 // cannot be loaded at all (for example, if the directory does not exist),
 // then packages prints an error and does not include that
 // package in the results. However, if errors occur trying
@@ -1843,7 +1843,7 @@ func PackagesForBuild(args []string) []*Package {
 }
 
 // GoFilesPackage creates a package for building a collection of Go files
-// (typically named on the command line).  The target is named p.a for
+// (typically named on the command line). The target is named p.a for
 // package p or named after the first Go file for package main.
 func GoFilesPackage(gofiles []string) *Package {
 	// TODO: Remove this restriction.

src/cmd/go/internal/test/test.go

@@ -59,7 +59,7 @@ followed by detailed output for each failed package.
 the file pattern "*_test.go".
 Files whose names begin with "_" (including "_test.go") or "." are ignored.
 These additional files can contain test functions, benchmark functions, and
-example functions.  See 'go help testfunc' for more.
+example functions. See 'go help testfunc' for more.
 Each listed package causes the execution of a separate test binary.
 
 Test files that declare a package with the suffix "_test" will be compiled as a
@@ -68,7 +68,7 @@ separate package, and then linked and run with the main test binary.
 The go tool will ignore a directory named "testdata", making it available
 to hold ancillary data needed by the tests.
 
-By default, go test needs no arguments.  It compiles and tests the package
+By default, go test needs no arguments. It compiles and tests the package
 with source in the current directory, including tests, and runs the tests.
 
 The package is built in a temporary directory so it does not interfere with the
@@ -130,7 +130,7 @@ and flags that apply to the resulting test binary.
 
 Several of the flags control profiling and write an execution profile
 suitable for "go tool pprof"; run "go tool pprof -h" for more
-information.  The --alloc_space, --alloc_objects, and --show_bytes
+information. The --alloc_space, --alloc_objects, and --show_bytes
 options of pprof control how the information is presented.
 
 The following flags are recognized by the 'go test' command and
@@ -185,7 +185,7 @@ const testFlag2 = `
 
 	-cpu 1,2,4
 	    Specify a list of GOMAXPROCS values for which the tests or
-	    benchmarks should be executed.  The default is the current value
+	    benchmarks should be executed. The default is the current value
 	    of GOMAXPROCS.
 
 	-list regexp
@@ -238,7 +238,7 @@ profile the tests during execution:
 	    calling runtime.SetBlockProfileRate with n.
 	    See 'go doc runtime.SetBlockProfileRate'.
 	    The profiler aims to sample, on average, one blocking event every
-	    n nanoseconds the program spends blocked.  By default,
+	    n nanoseconds the program spends blocked. By default,
 	    if -test.blockprofile is set without this flag, all blocking events
 	    are recorded, equivalent to -test.blockprofilerate=1.
 
@@ -256,7 +256,7 @@ profile the tests during execution:
 
 	-memprofilerate n
 	    Enable more precise (and expensive) memory profiles by setting
-	    runtime.MemProfileRate.  See 'go doc runtime.MemProfileRate'.
+	    runtime.MemProfileRate. See 'go doc runtime.MemProfileRate'.
 	    To profile all memory allocations, use -test.memprofilerate=1
 	    and pass --alloc_space flag to the pprof tool.
 
@@ -361,8 +361,8 @@ comment is compiled but not executed. An example with no text after
 "Output:" is compiled, executed, and expected to produce no output.
 
 Godoc displays the body of ExampleXXX to demonstrate the use
-of the function, constant, or variable XXX.  An example of a method M with
-receiver type T or *T is named ExampleT_M.  There may be multiple examples
+of the function, constant, or variable XXX. An example of a method M with
+receiver type T or *T is named ExampleT_M. There may be multiple examples
 for a given function, constant, or variable, distinguished by a trailing _xxx,
 where xxx is a suffix not beginning with an upper case letter.
 

src/cmd/go/internal/work/build.go

@@ -103,8 +103,8 @@ and test commands:
 		a suffix to use in the name of the package installation directory,
 		in order to keep output separate from default builds.
 		If using the -race flag, the install suffix is automatically set to race
-		or, if set explicitly, has _race appended to it.  Likewise for the -msan
-		flag.  Using a -buildmode option that requires non-default compile flags
+		or, if set explicitly, has _race appended to it. Likewise for the -msan
+		flag. Using a -buildmode option that requires non-default compile flags
 		has a similar effect.
 	-ldflags 'flag list'
 		arguments to pass on each go tool link invocation.
@@ -2001,7 +2001,7 @@ func (b *Builder) runOut(dir string, desc string, env []string, cmdargs ...inter
 		// until the time of the explicit close, and the race would remain.
 		//
 		// On Unix systems, this results in ETXTBSY, which formats
-		// as "text file busy".  Rather than hard-code specific error cases,
+		// as "text file busy". Rather than hard-code specific error cases,
 		// we just look for that string. If this happens, sleep a little
 		// and try again. We let this happen three times, with increasing
 		// sleep lengths: 100+200+400 ms = 0.7 seconds.
@@ -3662,7 +3662,7 @@ const i int = 1 << 32
 `
 
 // Determine the size of int on the target system for the -intgosize option
-// of swig >= 2.0.9.  Run only once.
+// of swig >= 2.0.9. Run only once.
 func (b *Builder) swigDoIntSize(obj string) (intsize string, err error) {
 	if cfg.BuildN {
 		return "$INTBITS", nil

src/sort/search.go

@@ -24,7 +24,7 @@ package sort
 //
 // For instance, given a slice data sorted in ascending order,
 // the call Search(len(data), func(i int) bool { return data[i] >= 23 })
-// returns the smallest index i such that data[i] >= 23.  If the caller
+// returns the smallest index i such that data[i] >= 23. If the caller
 // wants to find whether 23 is in the slice, it must test data[i] == 23
 // separately.
 //

src/text/template/doc.go

@@ -81,14 +81,14 @@ data, defined in detail in the corresponding sections that follow.
 
 	{{if pipeline}} T1 {{end}}
 		If the value of the pipeline is empty, no output is generated;
-		otherwise, T1 is executed.  The empty values are false, 0, any
+		otherwise, T1 is executed. The empty values are false, 0, any
 		nil pointer or interface value, and any array, slice, map, or
 		string of length zero.
 		Dot is unaffected.
 
 	{{if pipeline}} T1 {{else}} T0 {{end}}
 		If the value of the pipeline is empty, T0 is executed;
-		otherwise, T1 is executed.  Dot is unaffected.
+		otherwise, T1 is executed. Dot is unaffected.
 
 	{{if pipeline}} T1 {{else if pipeline}} T0 {{end}}
 		To simplify the appearance of if-else chains, the else action
@@ -242,19 +242,19 @@ where $variable is the name of the variable. An action that declares a
 variable produces no output.
 
 If a "range" action initializes a variable, the variable is set to the
-successive elements of the iteration.  Also, a "range" may declare two
+successive elements of the iteration. Also, a "range" may declare two
 variables, separated by a comma:
 
 	range $index, $element := pipeline
 
 in which case $index and $element are set to the successive values of the
-array/slice index or map key and element, respectively.  Note that if there is
+array/slice index or map key and element, respectively. Note that if there is
 only one variable, it is assigned the element; this is opposite to the
 convention in Go range clauses.
 
 A variable's scope extends to the "end" action of the control structure ("if",
 "with", or "range") in which it is declared, or to the end of the template if
-there is no such control structure.  A template invocation does not inherit
+there is no such control structure. A template invocation does not inherit
 variables from the point of its invocation.
 
 When execution begins, $ is set to the data argument passed to Execute, that is,

src/time/time.go

@@ -337,7 +337,7 @@ func (d Weekday) String() string { return days[d] }
 // The zero Time value does not force a specific epoch for the time
 // representation. For example, to use the Unix epoch internally, we
 // could define that to distinguish a zero value from Jan 1 1970, that
-// time would be represented by sec=-1, nsec=1e9.  However, it does
+// time would be represented by sec=-1, nsec=1e9. However, it does
 // suggest a representation, namely using 1-1-1 00:00:00 UTC as the
 // epoch, and that's what we do.
 //
@@ -369,7 +369,7 @@ func (d Weekday) String() string { return days[d] }
 // everywhere.
 //
 // The calendar runs on an exact 400 year cycle: a 400-year calendar
-// printed for 1970-2469 will apply as well to 2370-2769.  Even the days
+// printed for 1970-2469 will apply as well to 2370-2769. Even the days
 // of the week match up. It simplifies the computations to choose the
 // cycle boundaries so that the exceptional years are always delayed as
 // long as possible. That means choosing a year equal to 1 mod 400, so
@@ -383,7 +383,7 @@ func (d Weekday) String() string { return days[d] }
 //
 // These three considerations—choose an epoch as early as possible, that
 // uses a year equal to 1 mod 400, and that is no more than 2⁶³ seconds
-// earlier than 1970—bring us to the year -292277022399.  We refer to
+// earlier than 1970—bring us to the year -292277022399. We refer to
 // this year as the absolute zero year, and to times measured as a uint64
 // seconds since this year as absolute times.
 //
@@ -394,9 +394,9 @@ func (d Weekday) String() string { return days[d] }
 // times.
 //
 // It is tempting to just use the year 1 as the absolute epoch, defining
-// that the routines are only valid for years >= 1.  However, the
+// that the routines are only valid for years >= 1. However, the
 // routines would then be invalid when displaying the epoch in time zones
-// west of UTC, since it is year 0.  It doesn't seem tenable to say that
+// west of UTC, since it is year 0. It doesn't seem tenable to say that
 // printing the zero time correctly isn't supported in half the time
 // zones. By comparison, it's reasonable to mishandle some times in
 // the year -292277022399.
@@ -721,8 +721,8 @@ func (d Duration) String() string {
 }
 
 // fmtFrac formats the fraction of v/10**prec (e.g., ".12345") into the
-// tail of buf, omitting trailing zeros.  it omits the decimal
-// point too when the fraction is 0.  It returns the index where the
+// tail of buf, omitting trailing zeros. it omits the decimal
+// point too when the fraction is 0. It returns the index where the
 // output bytes begin and the value v/10**prec.
 func fmtFrac(buf []byte, v uint64, prec int) (nw int, nv uint64) {
 	// Omit trailing zeros up to and including decimal point.
@@ -963,7 +963,7 @@ func absDate(abs uint64, full bool) (year int, month Month, day int, yday int) {
 
 	// Cut off years within a 4-year cycle.
 	// The last year is a leap year, so on the last day of that year,
-	// day / 365 will be 4 instead of 3.  Cut it back down to 3
+	// day / 365 will be 4 instead of 3. Cut it back down to 3
 	// by subtracting n>>2.
 	n = d / 365
 	n -= n >> 2

src/unicode/letter.go

@@ -46,7 +46,7 @@ type Range32 struct {
 
 // CaseRange represents a range of Unicode code points for simple (one
 // code point to one code point) case conversion.
-// The range runs from Lo to Hi inclusive, with a fixed stride of 1.  Deltas
+// The range runs from Lo to Hi inclusive, with a fixed stride of 1. Deltas
 // are the number to add to the code point to reach the code point for a
 // different case for that character. They may be negative. If zero, it
 // means the character is in the corresponding case. There is a special
@@ -308,7 +308,7 @@ func (special SpecialCase) ToLower(r rune) rune {
 }
 
 // caseOrbit is defined in tables.go as []foldPair. Right now all the
-// entries fit in uint16, so use uint16.  If that changes, compilation
+// entries fit in uint16, so use uint16. If that changes, compilation
 // will fail (the constants in the composite literal will not fit in uint16)
 // and the types here can change to uint32.
 type foldPair struct {