Add unit tests for matches! special case formatting

The unit tests cover version One and Two formatting

tests/source/macros/matches/version_one.rs

@@ -0,0 +1,134 @@
+//rustfmt-version: One
+
+// To visually verify the special case handling of `matches!` we include the equivalent match expr
+
+// issue #4462
+fn issue_4462() {
+matches!(c,
+    'x' | 'c' | 'b' | 'B' | '?' | 'h' | 'H' | 'i' | 'I' | 'l' | 'L' | 'q' | 'Q' | 'n'
+    | 'N' | 'f' | 'd' | 's' | 'p' | 'P');
+
+match c {
+    'x' | 'c' | 'b' | 'B' | '?' | 'h' | 'H' | 'i' | 'I' | 'l' | 'L' | 'q' | 'Q' | 'n'
+    | 'N' | 'f' | 'd' | 's' | 'p' | 'P' => {}
+}
+}
+
+// issue #4885
+fn issue_4885() {
+matches!(
+    c,
+    '\\' | '.' | '+' | '(' | ')' | '|' | '[' | ']' | '{' | '}' | '^' |
+    '$'  | '#' | '&' | '-' | '~' | '*' | '?'
+);
+
+match c {
+    '\\' | '.' | '+' | '(' | ')' | '|' | '[' | ']' | '{' | '}' | '^' |
+    '$'  | '#' | '&' | '-' | '~' | '*' | '?' => {}
+}
+}
+
+// issue #5176
+fn issue_5176() {
+matches!(self, | Self::A | Self::B);
+match self {
+    | Self::A | Self::B => {}
+}
+}
+
+// issue #5547
+fn issue_5547() {
+    matches!(something.very_very_very.long.even.more.fields, Some(very_long_field_name_name_to_check) if method(very_long_field_name));
+    match something.very_very_very.long.even.more.fields {
+        Some(very_long_field_name_name_to_check) if method(very_long_field_name) => {}
+    }
+}
+
+// other scenarios
+fn other_scenarios() {
+
+    // no guard with trailing comma
+    matches!(self, | Self::A | Self::B,);
+    match self {
+        | Self::A | Self::B => {}
+    }
+
+    // guard with trailing comma
+    matches!(something.very_very_very.long.even.more.fields, Some(very_long_field_name_name_to_check) if method(very_long_field_name),);
+    match something.very_very_very.long.even.more.fields {
+        Some(very_long_field_name_name_to_check) if method(very_long_field_name) => {}
+    }
+
+    // short expr and pattern, but guard is long.
+    matches!(something, Some(_) if method(very_long_input_1, very_long_input_2, very_long_input_3, very_long_input_4, very_long_input_5),);
+    match something {
+        Some(_) if method(very_long_input_1, very_long_input_2, very_long_input_3, very_long_input_4, very_long_input_5) => {}
+    }
+
+    // square brackets
+    matches![self, | Self::A | Self::B];
+    match self {
+        | Self::A | Self::B => {}
+    }
+    // curly braces
+    matches!{self, | Self::A | Self::B};
+    match self {
+        | Self::A | Self::B => {}
+    }
+}
+
+// nested matches! calls
+impl Mystruct {
+    pub(crate) fn is_expr(&self) -> bool {
+        matches!(
+            self,
+            OverflowableItem::Expr(..)
+                | OverflowableItem::MacroArg(MacroArg::Expr(..))
+                | OverflowableItem::MatchMacroItem(MatchMacroItem::Expr(..))
+        );
+
+        match self {
+            OverflowableItem::Expr(..)
+                | OverflowableItem::MacroArg(MacroArg::Expr(..))
+                | OverflowableItem::MatchMacroItem(MatchMacroItem::Expr(..)) => {}
+        }
+    }
+
+    pub(crate) fn is_expr_with_guard(&self) -> bool {
+        matches!(
+            self,
+            OverflowableItem::Expr(..)
+                | OverflowableItem::MacroArg(MacroArg::Expr(..))
+                | OverflowableItem::MatchMacroItem(MatchMacroItem::Expr(..))
+                if self.condition()
+        );
+
+        match self {
+            OverflowableItem::Expr(..)
+                | OverflowableItem::MacroArg(MacroArg::Expr(..))
+                | OverflowableItem::MatchMacroItem(MatchMacroItem::Expr(..))
+                if self.condition() => {}
+        }
+    }
+}
+
+fn multi_line_struct_pattern_with_guard() {
+    matches!(
+        token,
+        Token::Dimension {
+            value,
+            ref unit,
+            ..
+        } if num_context.is_ok(context.parsing_mode, value)
+    );
+
+    match token {
+        Token::Dimension {
+            value,
+            ref unit,
+            ..
+        } if num_context.is_ok(context.parsing_mode, value) => {
+            // body
+        },
+    }
+}

tests/source/macros/matches/version_two.rs

@@ -0,0 +1,134 @@
+//rustfmt-version: Two
+
+// To visually verify the special case handling of `matches!` we include the equivalent match expr
+
+// issue #4462
+fn issue_4462() {
+matches!(c,
+    'x' | 'c' | 'b' | 'B' | '?' | 'h' | 'H' | 'i' | 'I' | 'l' | 'L' | 'q' | 'Q' | 'n'
+    | 'N' | 'f' | 'd' | 's' | 'p' | 'P');
+
+match c {
+    'x' | 'c' | 'b' | 'B' | '?' | 'h' | 'H' | 'i' | 'I' | 'l' | 'L' | 'q' | 'Q' | 'n'
+    | 'N' | 'f' | 'd' | 's' | 'p' | 'P' => {}
+}
+}
+
+// issue #4885
+fn issue_4885() {
+matches!(
+    c,
+    '\\' | '.' | '+' | '(' | ')' | '|' | '[' | ']' | '{' | '}' | '^' |
+    '$'  | '#' | '&' | '-' | '~' | '*' | '?'
+);
+
+match c {
+    '\\' | '.' | '+' | '(' | ')' | '|' | '[' | ']' | '{' | '}' | '^' |
+    '$'  | '#' | '&' | '-' | '~' | '*' | '?' => {}
+}
+}
+
+// issue #5176
+fn issue_5176() {
+matches!(self, | Self::A | Self::B);
+match self {
+    | Self::A | Self::B => {}
+}
+}
+
+// issue #5547
+fn issue_5547() {
+    matches!(something.very_very_very.long.even.more.fields, Some(very_long_field_name_name_to_check) if method(very_long_field_name));
+    match something.very_very_very.long.even.more.fields {
+        Some(very_long_field_name_name_to_check) if method(very_long_field_name) => {}
+    }
+}
+
+// other scenarios
+fn other_scenarios() {
+
+    // no guard with trailing comma
+    matches!(self, | Self::A | Self::B,);
+    match self {
+        | Self::A | Self::B => {}
+    }
+
+    // guard with trailing comma
+    matches!(something.very_very_very.long.even.more.fields, Some(very_long_field_name_name_to_check) if method(very_long_field_name),);
+    match something.very_very_very.long.even.more.fields {
+        Some(very_long_field_name_name_to_check) if method(very_long_field_name) => {}
+    }
+
+    // short expr and pattern, but guard is long.
+    matches!(something, Some(_) if method(very_long_input_1, very_long_input_2, very_long_input_3, very_long_input_4, very_long_input_5),);
+    match something {
+        Some(_) if method(very_long_input_1, very_long_input_2, very_long_input_3, very_long_input_4, very_long_input_5) => {}
+    }
+
+    // square brackets
+    matches![self, | Self::A | Self::B];
+    match self {
+        | Self::A | Self::B => {}
+    }
+    // curly braces
+    matches!{self, | Self::A | Self::B};
+    match self {
+        | Self::A | Self::B => {}
+    }
+}
+
+// nested matches! calls
+impl Mystruct {
+    pub(crate) fn is_expr(&self) -> bool {
+        matches!(
+            self,
+            OverflowableItem::Expr(..)
+                | OverflowableItem::MacroArg(MacroArg::Expr(..))
+                | OverflowableItem::MatchMacroItem(MatchMacroItem::Expr(..))
+        );
+
+        match self {
+            OverflowableItem::Expr(..)
+                | OverflowableItem::MacroArg(MacroArg::Expr(..))
+                | OverflowableItem::MatchMacroItem(MatchMacroItem::Expr(..)) => {}
+        }
+    }
+
+    pub(crate) fn is_expr_with_guard(&self) -> bool {
+        matches!(
+            self,
+            OverflowableItem::Expr(..)
+                | OverflowableItem::MacroArg(MacroArg::Expr(..))
+                | OverflowableItem::MatchMacroItem(MatchMacroItem::Expr(..))
+                if self.condition()
+        );
+
+        match self {
+            OverflowableItem::Expr(..)
+                | OverflowableItem::MacroArg(MacroArg::Expr(..))
+                | OverflowableItem::MatchMacroItem(MatchMacroItem::Expr(..))
+                if self.condition() => {}
+        }
+    }
+}
+
+fn multi_line_struct_pattern_with_guard() {
+    matches!(
+        token,
+        Token::Dimension {
+            value,
+            ref unit,
+            ..
+        } if num_context.is_ok(context.parsing_mode, value)
+    );
+
+    match token {
+        Token::Dimension {
+            value,
+            ref unit,
+            ..
+        } if num_context.is_ok(context.parsing_mode, value) => {
+            // body
+        },
+    }
+}