C#: Improved pattern matching (#2411)

components/prism-csharp.js

@@ -47,7 +47,7 @@
 		typeDeclaration: 'class enum interface struct',
 		// contextual keywords
 		// ("var" and "dynamic" are missing because they are used like types)
-		contextual: 'add alias ascending async await by descending from get global group into join let nameof notnull on orderby partial remove select set unmanaged value when where where',
+		contextual: 'add alias and ascending async await by descending from get global group into join let nameof not notnull on or orderby partial remove select set unmanaged value when where where',
 		// all other keywords
 		other: 'abstract as base break case catch checked const continue default delegate do else event explicit extern finally fixed for foreach goto if implicit in internal is lock namespace new null operator out override params private protected public readonly ref return sealed sizeof stackalloc static switch this throw try typeof unchecked unsafe using virtual volatile while yield'
 	};
@@ -68,6 +68,7 @@
 	var genericName = replace(/<<0>>(?:\s*<<1>>)?/.source, [name, generic]);
 	var identifier = replace(/(?!<<0>>)<<1>>(?:\s*\.\s*<<1>>)*/.source, [nonTypeKeywords, genericName]);
 	var array = /\[\s*(?:,\s*)*\]/.source;
+	var typeExpressionWithoutTuple = replace(/<<0>>(?:\s*(?:\?\s*)?<<1>>)*(?:\s*\?)?/.source, [identifier, array]);
 	var tupleElement = replace(/[^,()<>[\];=+\-*/%&|^]|<<0>>|<<1>>|<<2>>/.source, [generic, nestedRound, array])
 	var tuple = replace(/\(<<0>>+(?:,<<0>>+)+\)/.source, [tupleElement]);
 	var typeExpression = replace(/(?:<<0>>|<<1>>)(?:\s*(?:\?\s*)?<<2>>)*(?:\s*\?)?/.source, [tuple, identifier, array]);
@@ -150,14 +151,14 @@
 				// Casts and checks via as and is.
 				// as Foo<A>, is Bar<B>
 				// (things like if(a is Foo b) is covered by variable declaration)
-				pattern: re(/(\b(?:is|as)\s+)<<0>>/.source, [typeExpression]),
+				pattern: re(/(\b(?:is(?:\s+not)?|as)\s+)<<0>>/.source, [typeExpressionWithoutTuple]),
 				lookbehind: true,
 				inside: typeInside
 			},
 			{
 				// Variable, field and parameter declaration
 				// (Foo bar, Bar baz, Foo[,,] bay, Foo<Bar, FooBar<Bar>> bax)
-				pattern: re(/\b<<0>>(?=\s+(?!<<1>>)<<2>>(?:\s*[=,;:{)\]]|\s+in))/.source, [typeExpression, nonContextualKeywords, name]),
+				pattern: re(/\b<<0>>(?=\s+(?!<<1>>)<<2>>(?:\s*[=,;:{)\]]|\s+(?:in|when)\b))/.source, [typeExpression, nonContextualKeywords, name]),
 				inside: typeInside
 			}
 		],

tests/languages/csharp/class-name-variables-parameters_feature.test

@@ -7,6 +7,14 @@ void Foo(Foo a, Bar<Foo> b, Bar[, ] c, Foo<(int, int)> d);
 Bar<Foo> Abc => 0;
 Bar<Foo>.FooBar<IFoo> Abc;
 
+if (foo is Bar)
+if (foo is not Bar)
+if (foo is null)
+if (foo is not null)
+if (t is (int, string))
+if ((e1, e2) is (0, int i) or (int i, 0))
+var baz = foo as Bar;
+
 ----------------------------------------------------
 
 [
@@ -113,6 +121,84 @@ Bar<Foo>.FooBar<IFoo> Abc;
 		["punctuation", ">"]
 	]],
 	" Abc",
+	["punctuation", ";"],
+
+	["keyword", "if"],
+	["punctuation", "("],
+	"foo ",
+	["keyword", "is"],
+	["class-name", [
+		"Bar"
+	]],
+	["punctuation", ")"],
+	["keyword", "if"],
+	["punctuation", "("],
+	"foo ",
+	["keyword", "is"],
+	["keyword", "not"],
+	["class-name", [
+		"Bar"
+	]],
+	["punctuation", ")"],
+	["keyword", "if"],
+	["punctuation", "("],
+	"foo ",
+	["keyword", "is"],
+	["keyword", "null"],
+	["punctuation", ")"],
+	["keyword", "if"],
+	["punctuation", "("],
+	"foo ",
+	["keyword", "is"],
+	["keyword", "not"],
+	["keyword", "null"],
+	["punctuation", ")"],
+	["keyword", "if"],
+	["punctuation", "("],
+	"t ",
+	["keyword", "is"],
+	["punctuation", "("],
+	["keyword", "int"],
+	["punctuation", ","],
+	["keyword", "string"],
+	["punctuation", ")"],
+	["punctuation", ")"],
+	["keyword", "if"],
+	["punctuation", "("],
+	["punctuation", "("],
+	"e1",
+	["punctuation", ","],
+	" e2",
+	["punctuation", ")"],
+	["keyword", "is"],
+	["punctuation", "("],
+	["number", "0"],
+	["punctuation", ","],
+	["class-name", [
+		["keyword", "int"]
+	]],
+	" i",
+	["punctuation", ")"],
+	["keyword", "or"],
+	["punctuation", "("],
+	["class-name", [
+		["keyword", "int"]
+	]],
+	" i",
+	["punctuation", ","],
+	["number", "0"],
+	["punctuation", ")"],
+	["punctuation", ")"],
+	["class-name", [
+		["keyword", "var"]
+	]],
+	" baz ",
+	["operator", "="],
+	" foo ",
+	["keyword", "as"],
+	["class-name", [
+		"Bar"
+	]],
 	["punctuation", ";"]
 ]
 

tests/languages/csharp/keyword_feature.test

@@ -1,6 +1,7 @@
 abstract
 add
 alias
+and
 as
 ascending
 async
@@ -54,11 +55,13 @@ long
 nameof
 namespace;
 new;
+not
 notnull
 null
 object
 on
 operator
+or
 orderby
 out
 override
@@ -109,6 +112,7 @@ yield
 	["keyword", "abstract"],
 	["keyword", "add"],
 	["keyword", "alias"],
+	["keyword", "and"],
 	["keyword", "as"],
 	["keyword", "ascending"],
 	["keyword", "async"],
@@ -162,11 +166,13 @@ yield
 	["keyword", "nameof"],
 	["keyword", "namespace"], ["punctuation", ";"],
 	["keyword", "new"], ["punctuation", ";"],
+	["keyword", "not"],
 	["keyword", "notnull"],
 	["keyword", "null"],
 	["keyword", "object"],
 	["keyword", "on"],
 	["keyword", "operator"],
+	["keyword", "or"],
 	["keyword", "orderby"],
 	["keyword", "out"],
 	["keyword", "override"],