[dev.typealias] spec: use term 'embedded field' rather than 'anonymou…

…s field'

First steps towards defining type aliases in the spec.
This is a nomenclature clarification, not a language change.

The spec used all three terms 'embedded type', 'anonymous field',
and 'embedded field'. Users where using the terms inconsistently.

The notion of an 'anonymous' field was always misleading since they
always had a de-facto name. With type aliases that name becomes even
more important because we may have different names for the same type.

Use the term 'embedded field' consistently and remove competing
terminology.

For #18130.

Change-Id: I2083bbc85788cab0b2e2cb1ff58b2f979491f001
Reviewed-on: https://go-review.googlesource.com/35108
Reviewed-by: Alan Donovan <adonovan@google.com>
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

doc/go_spec.html

@@ -1,6 +1,6 @@
 <!--{
 	"Title": "The Go Programming Language Specification",
-	"Subtitle": "Version of November 18, 2016",
+	"Subtitle": "Version of January 31, 2017",
 	"Path": "/ref/spec"
 }-->
 
@@ -738,7 +738,7 @@ <h3 id="Method_sets">Method sets</h3>
 The method set of the corresponding <a href="#Pointer_types">pointer type</a> <code>*T</code>
 is the set of all methods declared with receiver <code>*T</code> or <code>T</code>
 (that is, it also contains the method set of <code>T</code>).
-Further rules apply to structs containing anonymous fields, as described
+Further rules apply to structs containing embedded fields, as described
 in the section on <a href="#Struct_types">struct types</a>.
 Any other type has an empty method set.
 In a method set, each method must have a
@@ -947,16 +947,16 @@ <h3 id="Struct_types">Struct types</h3>
 <p>
 A struct is a sequence of named elements, called fields, each of which has a
 name and a type. Field names may be specified explicitly (IdentifierList) or
-implicitly (AnonymousField).
+implicitly (EmbeddedField).
 Within a struct, non-<a href="#Blank_identifier">blank</a> field names must
 be <a href="#Uniqueness_of_identifiers">unique</a>.
 </p>
 
 <pre class="ebnf">
-StructType     = "struct" "{" { FieldDecl ";" } "}" .
-FieldDecl      = (IdentifierList Type | AnonymousField) [ Tag ] .
-AnonymousField = [ "*" ] TypeName .
-Tag            = string_lit .
+StructType    = "struct" "{" { FieldDecl ";" } "}" .
+FieldDecl     = (IdentifierList Type | EmbeddedField) [ Tag ] .
+EmbeddedField = [ "*" ] TypeName .
+Tag           = string_lit .
 </pre>
 
 <pre>
@@ -974,16 +974,15 @@ <h3 id="Struct_types">Struct types</h3>
 </pre>
 
 <p>
-A field declared with a type but no explicit field name is an <i>anonymous field</i>,
-also called an <i>embedded</i> field or an embedding of the type in the struct.
-An embedded type must be specified as
+A field declared with a type but no explicit field name is called an <i>embedded field</i>.
+An embedded field must be specified as
 a type name <code>T</code> or as a pointer to a non-interface type name <code>*T</code>,
 and <code>T</code> itself may not be
 a pointer type. The unqualified type name acts as the field name.
 </p>
 
 <pre>
-// A struct with four anonymous fields of type T1, *T2, P.T3 and *P.T4
+// A struct with four embedded fields of types T1, *T2, P.T3 and *P.T4
 struct {
 	T1        // field name is T1
 	*T2       // field name is T2
@@ -1000,15 +999,15 @@ <h3 id="Struct_types">Struct types</h3>
 
 <pre>
 struct {
-	T     // conflicts with anonymous field *T and *P.T
-	*T    // conflicts with anonymous field T and *P.T
-	*P.T  // conflicts with anonymous field T and *T
+	T     // conflicts with embedded field *T and *P.T
+	*T    // conflicts with embedded field T and *P.T
+	*P.T  // conflicts with embedded field T and *T
 }
 </pre>
 
 <p>
 A field or <a href="#Method_declarations">method</a> <code>f</code> of an
-anonymous field in a struct <code>x</code> is called <i>promoted</i> if
+embedded field in a struct <code>x</code> is called <i>promoted</i> if
 <code>x.f</code> is a legal <a href="#Selectors">selector</a> that denotes
 that field or method <code>f</code>.
 </p>
@@ -1025,15 +1024,15 @@ <h3 id="Struct_types">Struct types</h3>
 </p>
 <ul>
 	<li>
-	If <code>S</code> contains an anonymous field <code>T</code>,
+	If <code>S</code> contains an embedded field <code>T</code>,
 	the <a href="#Method_sets">method sets</a> of <code>S</code>
 	and <code>*S</code> both include promoted methods with receiver
 	<code>T</code>. The method set of <code>*S</code> also
 	includes promoted methods with receiver <code>*T</code>.
 	</li>
 
 	<li>
-	If <code>S</code> contains an anonymous field <code>*T</code>,
+	If <code>S</code> contains an embedded field <code>*T</code>,
 	the method sets of <code>S</code> and <code>*S</code> both
 	include promoted methods with receiver <code>T</code> or
 	<code>*T</code>.
@@ -1434,8 +1433,8 @@ <h3 id="Type_identity">Type identity</h3>
 	<li>Two struct types are identical if they have the same sequence of fields,
 	    and if corresponding fields have the same names, and identical types,
 	    and identical tags.
-	    Two anonymous fields are considered to have the same name. Lower-case field
-	    names from different packages are always different.</li>
+	    <a href="#Exported_identifiers">Non-exported</a> field names from different
+	    packages are always different.</li>
 
 	<li>Two pointer types are identical if they have identical base types.</li>
 
@@ -1445,8 +1444,9 @@ <h3 id="Type_identity">Type identity</h3>
 	    Parameter and result names are not required to match.</li>
 
 	<li>Two interface types are identical if they have the same set of methods
-	    with the same names and identical function types. Lower-case method names from
-	    different packages are always different. The order of the methods is irrelevant.</li>
+	    with the same names and identical function types.
+	    <a href="#Exported_identifiers">Non-exported</a> method names from different
+	    packages are always different. The order of the methods is irrelevant.</li>
 
 	<li>Two map types are identical if they have identical key and value types.</li>
 
@@ -1891,7 +1891,7 @@ <h3 id="Type_declarations">Type declarations</h3>
 type PtrMutex *Mutex
 
 // The method set of *PrintableMutex contains the methods
-// Lock and Unlock bound to its anonymous field Mutex.
+// Lock and Unlock bound to its embedded field Mutex.
 type PrintableMutex struct {
 	Mutex
 }
@@ -2492,13 +2492,13 @@ <h3 id="Selectors">Selectors</h3>
 A selector <code>f</code> may denote a field or method <code>f</code> of
 a type <code>T</code>, or it may refer
 to a field or method <code>f</code> of a nested
-<a href="#Struct_types">anonymous field</a> of <code>T</code>.
-The number of anonymous fields traversed
+<a href="#Struct_types">embedded field</a> of <code>T</code>.
+The number of embedded fields traversed
 to reach <code>f</code> is called its <i>depth</i> in <code>T</code>.
 The depth of a field or method <code>f</code>
 declared in <code>T</code> is zero.
 The depth of a field or method <code>f</code> declared in
-an anonymous field <code>A</code> in <code>T</code> is the
+an embedded field <code>A</code> in <code>T</code> is the
 depth of <code>f</code> in <code>A</code> plus one.
 </p>