Debugging attempts

Author: JarredAllen

clippy_lints/src/option_if_let_else.rs

@@ -1,5 +1,5 @@
 use crate::utils::sugg::Sugg;
-use crate::utils::{match_type, match_qpath, paths, span_lint_and_sugg};
+use crate::utils::{match_qpath, match_type, paths, span_lint, span_lint_and_sugg};
 use if_chain::if_chain;
 
 use rustc_errors::Applicability;
@@ -42,54 +42,61 @@ declare_clippy_lint! {
 
 declare_lint_pass!(OptionIfLetElse => [OPTION_IF_LET_ELSE]);
 
-/// If this is the option_if_let_else thing we're detecting, then this
-/// function returns Some(Option<_> compared, value if Option is Some,
-/// value if Option is None). Otherwise, it returns None
+/// If this is the option if let/else thing we're detecting, then this
+/// function returns Some(Option<_> compared, expression if Option is
+/// Some, expression if Option is None). Otherwise, it returns None
 fn detect_option_if_let_else<'a>(
     cx: &LateContext<'_, '_>,
     expr: &'a Expr<'_>,
 ) -> Option<(&'a Expr<'a>, &'a Expr<'a>, &'a Expr<'a>)> {
-    if_chain! {
-        if let ExprKind::Match(let_body, arms, MatchSource::IfLetDesugar { contains_else_clause: true } ) = &expr.kind;
-        if arms.len() == 2;
-        if match_type(cx, &cx.tables.expr_ty(let_body), &paths::OPTION);
-        if let PatKind::TupleStruct(path, &[inner_pat], _) = &arms[0].pat.kind;
-        if let PatKind::Wild | PatKind::Binding(..) = &inner_pat.kind;
-        then {
-            let (some_body, none_body) = if match_qpath(path, &paths::OPTION_SOME) {
-                (arms[0].body, arms[1].body)
-            } else {
-                (arms[1].body, arms[0].body)
-            };
-            Some((let_body, some_body, none_body))
-        } else {
-            None
+    if let ExprKind::Match(let_body, arms, MatchSource::IfLetDesugar{contains_else_clause: true}) = &expr.kind {
+        dbg!("Found if let/else stmt");
+        if arms.len() == 2 {
+            dbg!("If let/else statement has two arms");
+            if match_type(cx, &cx.tables.expr_ty(let_body), &paths::OPTION) {
+                dbg!("rhs of if let is Option<T>");
+                if let PatKind::TupleStruct(path, &[inner_pat], _) = &arms[0].pat.kind {
+                    dbg!("arm0 is TupleStruct");
+                    if let PatKind::Wild | PatKind::Binding(..) = &inner_pat.kind {
+                        dbg!("inside of Some(x) matches anything");
+                        let (some_body, none_body) = if match_qpath(path, &paths::OPTION_SOME) {
+                            (arms[0].body, arms[1].body)
+                        } else {
+                            (arms[1].body, arms[0].body)
+                        };
+                        return Some((let_body, some_body, none_body));
+                    }
+                }
+            }
         }
     }
+    None
 }
 
-/// Lint the option_if_let_else thing we're avoiding
-fn check_option_if_let_else(cx: &LateContext<'_, '_>, expr: &Expr<'_>) {
-    if let Some((option, map, else_func)) = detect_option_if_let_else(cx, expr) {
-        span_lint_and_sugg(
+impl<'a, 'tcx> LateLintPass<'a, 'tcx> for OptionIfLetElse {
+    fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
+        span_lint(
             cx,
             OPTION_IF_LET_ELSE,
             expr.span,
-            "use Option::map_or here",
-            "try",
-            format!(
-                "{}.map_or({}, {})",
-                Sugg::hir(cx, option, ".."),
-                Sugg::hir(cx, else_func, ".."),
-                Sugg::hir(cx, map, "..")
-            ),
-            Applicability::MachineApplicable,
+            "OptionIfLetElse::check_expr was run on this span",
         );
-    }
-}
-
-impl LateLintPass<'_, '_> for OptionIfLetElse {
-    fn check_expr(&mut self, cx: &LateContext<'_, '_>, expr: &Expr<'_>) {
-        check_option_if_let_else(cx, expr);
+        return;
+        if let Some((option, map, else_func)) = detect_option_if_let_else(cx, expr) {
+            span_lint_and_sugg(
+                cx,
+                OPTION_IF_LET_ELSE,
+                expr.span,
+                "use Option::map_or_else instead of an if let/else",
+                "try",
+                format!(
+                    "{}.map_or_else({}, {})",
+                    Sugg::hir(cx, option, ".."),
+                    Sugg::hir(cx, else_func, ".."),
+                    Sugg::hir(cx, map, "..")
+                ),
+                Applicability::MachineApplicable,
+            );
+        }
     }
 }

src/lintlist/mod.rs

@@ -1522,7 +1522,7 @@ pub const ALL_LINTS: [Lint; 360] = [
     Lint {
         name: "option_if_let_else",
         group: "style",
-        desc: "default lint description",
+        desc: "reimplementation of Option::map_or",
         deprecation: None,
         module: "option_if_let_else",
     },

tests/ui/option_if_let_else.rs

@@ -1,10 +1,19 @@
 #![warn(clippy::option_if_let_else)]
 
+fn bad1(string: Option<&str>) -> (bool, &str) {
+    if let Some(x) = string {
+        (true, x)
+    } else {
+        (false, "hello")
+    }
+}
+
 fn main() {
     let optional = Some(5);
-    if let Some(x) = optional {
-        x+2
+    let _ = if let Some(x) = optional {
+        x + 2
     } else {
         5
-    }
+    };
+    let _ = bad1(None);
 }