diff --git a/src/bytes/bytes_test.go b/src/bytes/bytes_test.go
index f18915c879e..9547ede312f 100644
--- a/src/bytes/bytes_test.go
+++ b/src/bytes/bytes_test.go
@@ -1224,7 +1224,7 @@ func TestMap(t *testing.T) {
 	// Run a couple of awful growth/shrinkage tests
 	a := tenRunes('a')
 
-	// 1.  Grow. This triggers two reallocations in Map.
+	// 1. Grow. This triggers two reallocations in Map.
 	maxRune := func(r rune) rune { return unicode.MaxRune }
 	m := Map(maxRune, []byte(a))
 	expect := tenRunes(unicode.MaxRune)
diff --git a/src/cmd/cgo/doc.go b/src/cmd/cgo/doc.go
index ef5272299bb..7e8486874ef 100644
--- a/src/cmd/cgo/doc.go
+++ b/src/cmd/cgo/doc.go
@@ -127,7 +127,7 @@ 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
 build constraint "cgo" if cgo is enabled. The special import "C"
 implies the "cgo" build constraint, as though the file also said
-"//go:build cgo".  Therefore, if cgo is disabled, files that import
+"//go:build cgo". Therefore, if cgo is disabled, files that import
 "C" will not be built by the go tool. (For more about build constraints
 see https://golang.org/pkg/go/build/#hdr-Build_Constraints).
 
diff --git a/src/cmd/cgo/gcc.go b/src/cmd/cgo/gcc.go
index 886ddf2d461..d1b629057ab 100644
--- a/src/cmd/cgo/gcc.go
+++ b/src/cmd/cgo/gcc.go
@@ -1056,7 +1056,7 @@ func (p *Package) rewriteCall(f *File, call *Call) (string, bool) {
 func (p *Package) needsPointerCheck(f *File, t ast.Expr, arg ast.Expr) bool {
 	// An untyped nil does not need a pointer check, and when
 	// _cgoCheckPointer returns the untyped nil the type assertion we
-	// are going to insert will fail.  Easier to just skip nil arguments.
+	// are going to insert will fail. Easier to just skip nil arguments.
 	// TODO: Note that this fails if nil is shadowed.
 	if id, ok := arg.(*ast.Ident); ok && id.Name == "nil" {
 		return false
@@ -3010,7 +3010,7 @@ func (c *typeConv) FuncType(dtype *dwarf.FuncType, pos token.Pos) *FuncType {
 	for i, f := range dtype.ParamType {
 		// gcc's DWARF generator outputs a single DotDotDotType parameter for
 		// function pointers that specify no parameters (e.g. void
-		// (*__cgo_0)()).  Treat this special case as void. This case is
+		// (*__cgo_0)()). Treat this special case as void. This case is
 		// invalid according to ISO C anyway (i.e. void (*__cgo_1)(...) is not
 		// legal).
 		if _, ok := f.(*dwarf.DotDotDotType); ok && i == 0 {
@@ -3081,7 +3081,7 @@ func (c *typeConv) Struct(dt *dwarf.StructType, pos token.Pos) (expr *ast.Struct
 	off := int64(0)
 
 	// Rename struct fields that happen to be named Go keywords into
-	// _{keyword}.  Create a map from C ident -> Go ident. The Go ident will
+	// _{keyword}. Create a map from C ident -> Go ident. The Go ident will
 	// be mangled. Any existing identifier that already has the same name on
 	// the C-side will cause the Go-mangled version to be prefixed with _.
 	// (e.g. in a struct with fields '_type' and 'type', the latter would be
@@ -3309,7 +3309,7 @@ func godefsFields(fld []*ast.Field) {
 // fieldPrefix returns the prefix that should be removed from all the
 // field names when generating the C or Go code. For generated
 // C, we leave the names as is (tv_sec, tv_usec), since that's what
-// people are used to seeing in C.  For generated Go code, such as
+// people are used to seeing in C. For generated Go code, such as
 // package syscall's data structures, we drop a common prefix
 // (so sec, usec, which will get turned into Sec, Usec for exporting).
 func fieldPrefix(fld []*ast.Field) string {
@@ -3456,7 +3456,7 @@ func (c *typeConv) badCFType(dt *dwarf.TypedefType) bool {
 // Tagged pointer support
 // Low-bit set means tagged object, next 3 bits (currently)
 // define the tagged object class, next 4 bits are for type
-// information for the specific tagged object class.  Thus,
+// information for the specific tagged object class. Thus,
 // the low byte is for type info, and the rest of a pointer
 // (32 or 64-bit) is for payload, whatever the tagged class.
 //
diff --git a/src/cmd/cgo/internal/test/buildid_linux.go b/src/cmd/cgo/internal/test/buildid_linux.go
index 84d3edb664e..7e0fd0fd126 100644
--- a/src/cmd/cgo/internal/test/buildid_linux.go
+++ b/src/cmd/cgo/internal/test/buildid_linux.go
@@ -4,9 +4,9 @@
 
 package cgotest
 
-// Test that we have no more than one build ID.  In the past we used
+// Test that we have no more than one build ID. In the past we used
 // to generate a separate build ID for each package using cgo, and the
-// linker concatenated them all.  We don't want that--we only want
+// linker concatenated them all. We don't want that--we only want
 // one.
 
 import (
@@ -42,7 +42,7 @@ sections:
 		for len(d) > 0 {
 
 			// ELF standards differ as to the sizes in
-			// note sections.  Both the GNU linker and
+			// note sections. Both the GNU linker and
 			// gold always generate 32-bit sizes, so that
 			// is what we assume here.
 
diff --git a/src/cmd/cgo/internal/test/callback.go b/src/cmd/cgo/internal/test/callback.go
index 478bf8294af..8f8dd8fded6 100644
--- a/src/cmd/cgo/internal/test/callback.go
+++ b/src/cmd/cgo/internal/test/callback.go
@@ -40,7 +40,7 @@ func nestedCall(f func()) {
 	callbackMutex.Unlock()
 
 	// Pass the address of i because the C function was written to
-	// take a pointer.  We could pass an int if we felt like
+	// take a pointer. We could pass an int if we felt like
 	// rewriting the C code.
 	C.callback(unsafe.Pointer(&i))
 
diff --git a/src/cmd/cgo/internal/test/gcc68255/a.go b/src/cmd/cgo/internal/test/gcc68255/a.go
index e106dee3ec0..cc4804b90bd 100644
--- a/src/cmd/cgo/internal/test/gcc68255/a.go
+++ b/src/cmd/cgo/internal/test/gcc68255/a.go
@@ -3,7 +3,7 @@
 // license that can be found in the LICENSE file.
 
 // Test that it's OK to have C code that does nothing other than
-// initialize a global variable.  This used to fail with gccgo.
+// initialize a global variable. This used to fail with gccgo.
 
 package gcc68255
 
diff --git a/src/cmd/cgo/internal/teststdio/testdata/fib.go b/src/cmd/cgo/internal/teststdio/testdata/fib.go
index 96173683353..69147880c20 100644
--- a/src/cmd/cgo/internal/teststdio/testdata/fib.go
+++ b/src/cmd/cgo/internal/teststdio/testdata/fib.go
@@ -5,7 +5,7 @@
 //go:build test_run
 
 // Compute Fibonacci numbers with two goroutines
-// that pass integers back and forth.  No actual
+// that pass integers back and forth. No actual
 // concurrency, just threads and synchronization
 // and foreign code on multiple pthreads.
 
diff --git a/src/strings/strings_test.go b/src/strings/strings_test.go
index b10b5f05cca..edfeb0e8138 100644
--- a/src/strings/strings_test.go
+++ b/src/strings/strings_test.go
@@ -694,7 +694,7 @@ func rot13(r rune) rune {
 func TestMap(t *testing.T) {
 	// Run a couple of awful growth/shrinkage tests
 	a := tenRunes('a')
-	// 1.  Grow. This triggers two reallocations in Map.
+	// 1. Grow. This triggers two reallocations in Map.
 	maxRune := func(rune) rune { return unicode.MaxRune }
 	m := Map(maxRune, a)
 	expect := tenRunes(unicode.MaxRune)