Fix Issue 6470: Preserve Space after colon if followed by absolute path declaration (::)

src/expr.rs

@@ -1786,7 +1786,7 @@ pub(crate) fn wrap_struct_field(
 }
 
 pub(crate) fn struct_lit_field_separator(config: &Config) -> &str {
-    colon_spaces(config)
+    colon_spaces(config, false)
 }
 
 pub(crate) fn rewrite_field(

src/items.rs

@@ -42,8 +42,8 @@ const DEFAULT_VISIBILITY: ast::Visibility = ast::Visibility {
     tokens: None,
 };
 
-fn type_annotation_separator(config: &Config) -> &str {
-    colon_spaces(config)
+fn type_annotation_separator(config: &Config, force_space_after_colon: bool) -> &str {
+    colon_spaces(config, force_space_after_colon)
 }
 
 // Statements of the form
@@ -96,7 +96,10 @@ impl Rewrite for ast::Local {
             let mut infix = String::with_capacity(32);
 
             if let Some(ref ty) = self.ty {
-                let separator = type_annotation_separator(context.config);
+                let force_space_after_colon =
+                    is_ty_kind_with_absolute_decl(&ty.clone().into_inner().kind);
+                let separator = type_annotation_separator(context.config, force_space_after_colon);
+
                 let ty_shape = if pat_str.contains('\n') {
                     shape.with_max_width(context.config)
                 } else {
@@ -1890,10 +1893,14 @@ fn rewrite_ty<R: Rewrite>(
     Ok(result)
 }
 
-fn type_annotation_spacing(config: &Config) -> (&str, &str) {
+fn type_annotation_spacing(config: &Config, force_space_after_colon: bool) -> (&str, &str) {
     (
         if config.space_before_colon() { " " } else { "" },
-        if config.space_after_colon() { " " } else { "" },
+        if force_space_after_colon || config.space_after_colon() {
+            " "
+        } else {
+            ""
+        },
     )
 }
 
@@ -1903,7 +1910,7 @@ pub(crate) fn rewrite_struct_field_prefix(
 ) -> RewriteResult {
     let vis = format_visibility(context, &field.vis);
     let safety = format_safety(field.safety);
-    let type_annotation_spacing = type_annotation_spacing(context.config);
+    let type_annotation_spacing = type_annotation_spacing(context.config, false);
     Ok(match field.ident {
         Some(name) => format!(
             "{vis}{safety}{}{}:",
@@ -1939,7 +1946,9 @@ pub(crate) fn rewrite_struct_field(
         return Ok(context.snippet(field.span()).to_owned());
     }
 
-    let type_annotation_spacing = type_annotation_spacing(context.config);
+    let force_space_after_colon =
+        is_ty_kind_with_absolute_decl(&field.ty.clone().into_inner().kind);
+    let type_annotation_spacing = type_annotation_spacing(context.config, force_space_after_colon);
     let prefix = rewrite_struct_field_prefix(context, field)?;
 
     let attrs_str = field.attrs.rewrite_result(context, shape)?;
@@ -2078,6 +2087,19 @@ impl<'a> StaticParts<'a> {
     }
 }
 
+fn is_ty_kind_with_absolute_decl(ty_kind: &ast::TyKind) -> bool {
+    match ty_kind {
+        ast::TyKind::Path(None, ast_path) => {
+            let segments = &ast_path.segments;
+            match segments.first() {
+                Some(path_segment) => path_segment.ident.name == symbol::kw::PathRoot,
+                None => false,
+            }
+        }
+        _ => false,
+    }
+}
+
 fn rewrite_static(
     context: &RewriteContext<'_>,
     static_parts: &StaticParts<'_>,
@@ -2091,7 +2113,11 @@ fn rewrite_static(
         return None;
     }
 
-    let colon = colon_spaces(context.config);
+    // if after a semicolon is absolute path declaration (::) need to force
+    //  space after colon, because ::: syntax cannot compile
+    let force_space_after_colon = is_ty_kind_with_absolute_decl(&static_parts.ty.kind);
+    let colon = colon_spaces(context.config, force_space_after_colon);
+
     let mut prefix = format!(
         "{}{}{}{} {}{}{}",
         format_visibility(context, static_parts.vis),
@@ -2294,7 +2320,7 @@ impl Rewrite for ast::Param {
                 let (before_comment, after_comment) =
                     get_missing_param_comments(context, self.pat.span, self.ty.span, shape);
                 result.push_str(&before_comment);
-                result.push_str(colon_spaces(context.config));
+                result.push_str(colon_spaces(context.config, false));
                 result.push_str(&after_comment);
                 let overhead = last_line_width(&result);
                 let max_width = shape
@@ -2322,7 +2348,7 @@ impl Rewrite for ast::Param {
                         !has_multiple_attr_lines,
                     )?;
                     result.push_str(&before_comment);
-                    result.push_str(colon_spaces(context.config));
+                    result.push_str(colon_spaces(context.config, false));
                     result.push_str(&after_comment);
                     let overhead = last_line_width(&result);
                     let max_width = shape

src/types.rs

@@ -435,7 +435,7 @@ where
 }
 
 fn type_bound_colon(context: &RewriteContext<'_>) -> &'static str {
-    colon_spaces(context.config)
+    colon_spaces(context.config, false)
 }
 
 // If the return type is multi-lined, then force to use multiple lines for

src/utils.rs

@@ -423,9 +423,9 @@ pub(crate) fn filtered_str_fits(snippet: &str, max_width: usize, shape: Shape) -
 }
 
 #[inline]
-pub(crate) fn colon_spaces(config: &Config) -> &'static str {
+pub(crate) fn colon_spaces(config: &Config, force_space_after_colon: bool) -> &'static str {
     let before = config.space_before_colon();
-    let after = config.space_after_colon();
+    let after = force_space_after_colon || config.space_after_colon();
     match (before, after) {
         (true, true) => " : ",
         (true, false) => " :",

tests/source/issue-6470/case-1.rs

@@ -0,0 +1,44 @@
+// rustfmt-space_after_colon: false
+
+struct SomeStruct {
+    field1: ::some_crate::Thing,
+    field2 : ::some_crate::Thing,
+
+    field3:some_crate::Thing,
+    field4 :some_crate::Thing,
+    field5: some_crate::Thing,
+    field6 : some_crate::Thing,
+
+    field7:i32,
+    field8 :i32,
+    field9: i32,
+    field10 : i32,
+}
+
+const THING1: ::some_crate::SomeType = ::some_crate::SomeType::default();
+const THING2 : ::some_crate::SomeType = ::some_crate::SomeType::default();
+
+const THING3: some_crate::SomeType = some_crate::SomeType::default();
+const THING4 :some_crate::SomeType = some_crate::SomeType::default();
+const THING5: some_crate::SomeType = some_crate::SomeType::default();
+const THING6 : some_crate::SomeType = some_crate::SomeType::default();
+
+const THING7: i32 = 0;
+const THING8 :i32 = 0;
+const THING9: i32 = 0;
+const THING10 : i32 = 0;
+
+fn main() {
+    let x1: ::some_crate::SomeType = ::some_crate::SomeType::default();
+    let x2 : ::some_crate::SomeType = ::some_crate::SomeType::default();
+
+    let x3:some_crate::SomeType = ::some_crate::SomeType::default();
+    let x4 : some_crate::SomeType = ::some_crate::SomeType::default();
+    let x5: some_crate::SomeType = ::some_crate::SomeType::default();
+    let x6 : some_crate::SomeType = ::some_crate::SomeType::default();
+
+    let x7: i32 = 0;
+    let x8 :i32 = 0;
+    let x9: i32 = 0;
+    let x10 : i32 = 0;
+}

tests/source/issue-6470/case-2.rs

@@ -0,0 +1,44 @@
+// rustfmt-space_after_colon: true
+
+struct SomeStruct {
+    field1: ::some_crate::Thing,
+    field2 : ::some_crate::Thing,
+
+    field3:some_crate::Thing,
+    field4 :some_crate::Thing,
+    field5: some_crate::Thing,
+    field6 : some_crate::Thing,
+
+    field7:i32,
+    field8 :i32,
+    field9: i32,
+    field10 : i32,
+}
+
+const THING1: ::some_crate::SomeType = ::some_crate::SomeType::default();
+const THING2 : ::some_crate::SomeType = ::some_crate::SomeType::default();
+
+const THING3: some_crate::SomeType = some_crate::SomeType::default();
+const THING4 :some_crate::SomeType = some_crate::SomeType::default();
+const THING5: some_crate::SomeType = some_crate::SomeType::default();
+const THING6 : some_crate::SomeType = some_crate::SomeType::default();
+
+const THING7: i32 = 0;
+const THING8 :i32 = 0;
+const THING9: i32 = 0;
+const THING10 : i32 = 0;
+
+fn main() {
+    let x1: ::some_crate::SomeType = ::some_crate::SomeType::default();
+    let x2 : ::some_crate::SomeType = ::some_crate::SomeType::default();
+
+    let x3:some_crate::SomeType = ::some_crate::SomeType::default();
+    let x4 : some_crate::SomeType = ::some_crate::SomeType::default();
+    let x5: some_crate::SomeType = ::some_crate::SomeType::default();
+    let x6 : some_crate::SomeType = ::some_crate::SomeType::default();
+
+    let x7: i32 = 0;
+    let x8 :i32 = 0;
+    let x9: i32 = 0;
+    let x10 : i32 = 0;
+}

tests/target/issue-6470/case-1.rs

@@ -0,0 +1,44 @@
+// rustfmt-space_after_colon: false
+
+struct SomeStruct {
+    field1: ::some_crate::Thing,
+    field2: ::some_crate::Thing,
+
+    field3:some_crate::Thing,
+    field4:some_crate::Thing,
+    field5:some_crate::Thing,
+    field6:some_crate::Thing,
+
+    field7:i32,
+    field8:i32,
+    field9:i32,
+    field10:i32,
+}
+
+const THING1: ::some_crate::SomeType = ::some_crate::SomeType::default();
+const THING2: ::some_crate::SomeType = ::some_crate::SomeType::default();
+
+const THING3:some_crate::SomeType = some_crate::SomeType::default();
+const THING4:some_crate::SomeType = some_crate::SomeType::default();
+const THING5:some_crate::SomeType = some_crate::SomeType::default();
+const THING6:some_crate::SomeType = some_crate::SomeType::default();
+
+const THING7:i32 = 0;
+const THING8:i32 = 0;
+const THING9:i32 = 0;
+const THING10:i32 = 0;
+
+fn main() {
+    let x1: ::some_crate::SomeType = ::some_crate::SomeType::default();
+    let x2: ::some_crate::SomeType = ::some_crate::SomeType::default();
+
+    let x3:some_crate::SomeType = ::some_crate::SomeType::default();
+    let x4:some_crate::SomeType = ::some_crate::SomeType::default();
+    let x5:some_crate::SomeType = ::some_crate::SomeType::default();
+    let x6:some_crate::SomeType = ::some_crate::SomeType::default();
+
+    let x7:i32 = 0;
+    let x8:i32 = 0;
+    let x9:i32 = 0;
+    let x10:i32 = 0;
+}

tests/target/issue-6470/case-2.rs

@@ -0,0 +1,44 @@
+// rustfmt-space_after_colon: true
+
+struct SomeStruct {
+    field1: ::some_crate::Thing,
+    field2: ::some_crate::Thing,
+
+    field3: some_crate::Thing,
+    field4: some_crate::Thing,
+    field5: some_crate::Thing,
+    field6: some_crate::Thing,
+
+    field7: i32,
+    field8: i32,
+    field9: i32,
+    field10: i32,
+}
+
+const THING1: ::some_crate::SomeType = ::some_crate::SomeType::default();
+const THING2: ::some_crate::SomeType = ::some_crate::SomeType::default();
+
+const THING3: some_crate::SomeType = some_crate::SomeType::default();
+const THING4: some_crate::SomeType = some_crate::SomeType::default();
+const THING5: some_crate::SomeType = some_crate::SomeType::default();
+const THING6: some_crate::SomeType = some_crate::SomeType::default();
+
+const THING7: i32 = 0;
+const THING8: i32 = 0;
+const THING9: i32 = 0;
+const THING10: i32 = 0;
+
+fn main() {
+    let x1: ::some_crate::SomeType = ::some_crate::SomeType::default();
+    let x2: ::some_crate::SomeType = ::some_crate::SomeType::default();
+
+    let x3: some_crate::SomeType = ::some_crate::SomeType::default();
+    let x4: some_crate::SomeType = ::some_crate::SomeType::default();
+    let x5: some_crate::SomeType = ::some_crate::SomeType::default();
+    let x6: some_crate::SomeType = ::some_crate::SomeType::default();
+
+    let x7: i32 = 0;
+    let x8: i32 = 0;
+    let x9: i32 = 0;
+    let x10: i32 = 0;
+}