spec: Merge ClassInvariant and StructInvariant

Their definition is identical, and therefore indistinguishable.

Author: CyberShadow

spec/class.dd

@@ -902,13 +902,13 @@ $(GNAME SharedStaticDestructor):
 $(H2 $(LNAME2 invariants, Class Invariants))
 
 $(GRAMMAR
-$(GNAME ClassInvariant):
+$(GNAME Invariant):
     $(D invariant $(LPAREN) $(RPAREN)) $(GLINK2 statement, BlockStatement)
     $(D invariant) $(GLINK2 statement, BlockStatement)
     $(D invariant $(LPAREN)) $(GLINK2 expression, AssertArguments) $(D $(RPAREN) ;)
 )
 
-    $(P $(I ClassInvariant) specify the relationships among the members of a class instance.
+    $(P Class $(I Invariant)s specify the relationships among the members of a class instance.
     Those relationships must hold for any interactions with the instance from its
     public interface.
     )
@@ -924,10 +924,10 @@ $(GNAME ClassInvariant):
 
     $(P There may be multiple invariants in a class. They are applied in lexical order.)
 
-    $(P $(I ClassInvariant)s must hold at the exit of the class constructor (if any),
+    $(P Class $(I Invariant)s must hold at the exit of the class constructor (if any),
     at the entry of the class destructor (if any).)
 
-    $(P $(I ClassInvariant)s must hold
+    $(P Class $(I Invariant)s must hold
     at the entry and exit of all public or exported non-static member functions.
     The order of application of invariants is:
     $(OL
@@ -983,7 +983,7 @@ $(GNAME ClassInvariant):
 
     $(IMPLEMENTATION_DEFINED
     $(OL
-    $(LI Whether the $(I Class Invariant) is executed at runtime or not. This is typically
+    $(LI Whether the class $(I Invariant) is executed at runtime or not. This is typically
     controlled with a compiler switch.)
     $(LI The behavior when the invariant does not hold is typically the same as
     for when $(GLINK2 expression, AssertExpression)s fail.)

spec/contracts.dd

@@ -34,7 +34,7 @@ $(H2 $(LNAME2 pre_post_contracts, Pre and Post Contracts))
 
 $(H2 $(LNAME2 Invariants, Invariants))
 
-        $(P See $(DDSUBLINK struct, StructInvariant, Struct Invariants) and $(DDSUBLINK class, invariants, Class Invariants).)
+        $(P See $(DDSUBLINK struct, Invariant, Struct Invariants) and $(DDSUBLINK class, invariants, Class Invariants).)
 
 
 $(H2 $(LNAME2 references, References))

spec/expression.dd

@@ -1933,11 +1933,11 @@ $(GNAME AssertArguments):
     )
 
     $(P If the first $(I AssignExpression) is a reference to a class instance for
-    which a $(DDSUBLINK spec/class, invariants, Class Invariant) exists, the $(I Class Invariant) must hold.
+    which a $(DDSUBLINK spec/class, invariants, class Invariant) exists, the class $(I Invariant) must hold.
     )
 
     $(P If the first $(I AssignExpression) is a pointer to a struct instance for
-    which a $(I Struct Invariant) exists, the $(I Struct Invariant) must hold.
+    which a struct $(I Invariant) exists, the struct $(I Invariant) must hold.
     )
 
     $(P The type of an $(I AssertExpression) is $(D void).

spec/module.dd

@@ -21,8 +21,7 @@ $(GNAME DeclDef):
     $(GLINK2 struct, Postblit)
     $(GLINK2 class, Allocator)
     $(GLINK2 class, Deallocator)
-    $(GLINK2 class, ClassInvariant)
-    $(GLINK2 struct, StructInvariant)
+    $(GLINK2 class, Invariant)
     $(GLINK2 unittest, UnitTest)
     $(GLINK2 class, AliasThis)
     $(GLINK2 class, StaticConstructor)

spec/struct.dd

@@ -1500,16 +1500,16 @@ void main()
 ---
 )
 
-$(H2 $(LNAME2 StructInvariant, Struct Invariants))
+$(H2 $(LNAME2 Invariant, Struct Invariants))
 
 $(GRAMMAR
-$(GNAME StructInvariant):
+$(GNAME Invariant):
     $(D invariant $(LPAREN) $(RPAREN)) $(GLINK2 statement, BlockStatement)
     $(D invariant) $(GLINK2 statement, BlockStatement)
     $(D invariant $(LPAREN)) $(GLINK2 expression, AssertArguments) $(D $(RPAREN) ;)
 )
 
-    $(P $(I StructInvariant)s specify the relationships among the members of a struct instance.
+    $(P Struct $(I Invariant)s specify the relationships among the members of a struct instance.
     Those relationships must hold for any interactions with the instance from its
     public interface.
     )
@@ -1525,10 +1525,10 @@ $(GNAME StructInvariant):
 
     $(P There may be multiple invariants in a struct. They are applied in lexical order.)
 
-    $(P $(I StructInvariant)s must hold at the exit of the struct constructor (if any),
+    $(P Struct $(I Invariant)s must hold at the exit of the struct constructor (if any),
     and at the entry of the struct destructor (if any).)
 
-    $(P $(I StructInvariant)s must hold
+    $(P Struct $(I Invariant)s must hold
     at the entry and exit of all public or exported non-static member functions.
     The order of application of invariants is:
     $(OL
@@ -1588,7 +1588,7 @@ $(GNAME StructInvariant):
 
     $(IMPLEMENTATION_DEFINED
     $(OL
-    $(LI Whether the $(I StructInvariant) is executed at runtime or not. This is typically
+    $(LI Whether the struct $(I Invariant) is executed at runtime or not. This is typically
     controlled with a compiler switch.)
     $(LI The behavior when the invariant does not hold is typically the same as
     for when $(GLINK2 expression, AssertExpression)s fail.)