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-rw-r--r--crates/ide_assists/src/handlers/extract_function.rs128
1 files changed, 109 insertions, 19 deletions
diff --git a/crates/ide_assists/src/handlers/extract_function.rs b/crates/ide_assists/src/handlers/extract_function.rs
index 5fdc8bf38..af9543766 100644
--- a/crates/ide_assists/src/handlers/extract_function.rs
+++ b/crates/ide_assists/src/handlers/extract_function.rs
@@ -75,7 +75,8 @@ pub(crate) fn extract_function(acc: &mut Assists, ctx: &AssistContext) -> Option
75 let insert_after = scope_for_fn_insertion(&body, anchor)?; 75 let insert_after = scope_for_fn_insertion(&body, anchor)?;
76 let module = ctx.sema.scope(&insert_after).module()?; 76 let module = ctx.sema.scope(&insert_after).module()?;
77 77
78 let vars_defined_in_body_and_outlive = vars_defined_in_body_and_outlive(ctx, &body); 78 let vars_defined_in_body_and_outlive =
79 vars_defined_in_body_and_outlive(ctx, &body, &node.parent().as_ref().unwrap_or(&node));
79 let ret_ty = body_return_ty(ctx, &body)?; 80 let ret_ty = body_return_ty(ctx, &body)?;
80 81
81 // FIXME: we compute variables that outlive here just to check `never!` condition 82 // FIXME: we compute variables that outlive here just to check `never!` condition
@@ -257,7 +258,7 @@ struct Function {
257 control_flow: ControlFlow, 258 control_flow: ControlFlow,
258 ret_ty: RetType, 259 ret_ty: RetType,
259 body: FunctionBody, 260 body: FunctionBody,
260 vars_defined_in_body_and_outlive: Vec<Local>, 261 vars_defined_in_body_and_outlive: Vec<OutlivedLocal>,
261} 262}
262 263
263#[derive(Debug)] 264#[derive(Debug)]
@@ -296,9 +297,9 @@ impl Function {
296 RetType::Expr(ty) => FunType::Single(ty.clone()), 297 RetType::Expr(ty) => FunType::Single(ty.clone()),
297 RetType::Stmt => match self.vars_defined_in_body_and_outlive.as_slice() { 298 RetType::Stmt => match self.vars_defined_in_body_and_outlive.as_slice() {
298 [] => FunType::Unit, 299 [] => FunType::Unit,
299 [var] => FunType::Single(var.ty(ctx.db())), 300 [var] => FunType::Single(var.local.ty(ctx.db())),
300 vars => { 301 vars => {
301 let types = vars.iter().map(|v| v.ty(ctx.db())).collect(); 302 let types = vars.iter().map(|v| v.local.ty(ctx.db())).collect();
302 FunType::Tuple(types) 303 FunType::Tuple(types)
303 } 304 }
304 }, 305 },
@@ -562,6 +563,12 @@ impl HasTokenAtOffset for FunctionBody {
562 } 563 }
563} 564}
564 565
566#[derive(Debug)]
567struct OutlivedLocal {
568 local: Local,
569 mut_usage_outside_body: bool,
570}
571
565/// Try to guess what user wants to extract 572/// Try to guess what user wants to extract
566/// 573///
567/// We have basically have two cases: 574/// We have basically have two cases:
@@ -707,10 +714,10 @@ fn has_exclusive_usages(ctx: &AssistContext, usages: &LocalUsages, body: &Functi
707 .any(|reference| reference_is_exclusive(reference, body, ctx)) 714 .any(|reference| reference_is_exclusive(reference, body, ctx))
708} 715}
709 716
710/// checks if this reference requires `&mut` access inside body 717/// checks if this reference requires `&mut` access inside node
711fn reference_is_exclusive( 718fn reference_is_exclusive(
712 reference: &FileReference, 719 reference: &FileReference,
713 body: &FunctionBody, 720 node: &dyn HasTokenAtOffset,
714 ctx: &AssistContext, 721 ctx: &AssistContext,
715) -> bool { 722) -> bool {
716 // we directly modify variable with set: `n = 0`, `n += 1` 723 // we directly modify variable with set: `n = 0`, `n += 1`
@@ -719,7 +726,7 @@ fn reference_is_exclusive(
719 } 726 }
720 727
721 // we take `&mut` reference to variable: `&mut v` 728 // we take `&mut` reference to variable: `&mut v`
722 let path = match path_element_of_reference(body, reference) { 729 let path = match path_element_of_reference(node, reference) {
723 Some(path) => path, 730 Some(path) => path,
724 None => return false, 731 None => return false,
725 }; 732 };
@@ -820,10 +827,16 @@ fn vars_defined_in_body(body: &FunctionBody, ctx: &AssistContext) -> Vec<Local>
820} 827}
821 828
822/// list local variables defined inside `body` that should be returned from extracted function 829/// list local variables defined inside `body` that should be returned from extracted function
823fn vars_defined_in_body_and_outlive(ctx: &AssistContext, body: &FunctionBody) -> Vec<Local> { 830fn vars_defined_in_body_and_outlive(
824 let mut vars_defined_in_body = vars_defined_in_body(&body, ctx); 831 ctx: &AssistContext,
825 vars_defined_in_body.retain(|var| var_outlives_body(ctx, body, var)); 832 body: &FunctionBody,
833 parent: &SyntaxNode,
834) -> Vec<OutlivedLocal> {
835 let vars_defined_in_body = vars_defined_in_body(&body, ctx);
826 vars_defined_in_body 836 vars_defined_in_body
837 .into_iter()
838 .filter_map(|var| var_outlives_body(ctx, body, var, parent))
839 .collect()
827} 840}
828 841
829/// checks if the relevant local was defined before(outside of) body 842/// checks if the relevant local was defined before(outside of) body
@@ -843,11 +856,23 @@ fn either_syntax(value: &Either<ast::IdentPat, ast::SelfParam>) -> &SyntaxNode {
843 } 856 }
844} 857}
845 858
846/// checks if local variable is used after(outside of) body 859/// returns usage details if local variable is used after(outside of) body
847fn var_outlives_body(ctx: &AssistContext, body: &FunctionBody, var: &Local) -> bool { 860fn var_outlives_body(
848 let usages = LocalUsages::find(ctx, *var); 861 ctx: &AssistContext,
862 body: &FunctionBody,
863 var: Local,
864 parent: &SyntaxNode,
865) -> Option<OutlivedLocal> {
866 let usages = LocalUsages::find(ctx, var);
849 let has_usages = usages.iter().any(|reference| body.preceedes_range(reference.range)); 867 let has_usages = usages.iter().any(|reference| body.preceedes_range(reference.range));
850 has_usages 868 if !has_usages {
869 return None;
870 }
871 let has_mut_usages = usages
872 .iter()
873 .filter(|reference| body.preceedes_range(reference.range))
874 .any(|reference| reference_is_exclusive(reference, parent, ctx));
875 Some(OutlivedLocal { local: var, mut_usage_outside_body: has_mut_usages })
851} 876}
852 877
853fn body_return_ty(ctx: &AssistContext, body: &FunctionBody) -> Option<RetType> { 878fn body_return_ty(ctx: &AssistContext, body: &FunctionBody) -> Option<RetType> {
@@ -927,16 +952,25 @@ fn format_replacement(ctx: &AssistContext, fun: &Function, indent: IndentLevel)
927 let mut buf = String::new(); 952 let mut buf = String::new();
928 match fun.vars_defined_in_body_and_outlive.as_slice() { 953 match fun.vars_defined_in_body_and_outlive.as_slice() {
929 [] => {} 954 [] => {}
930 [var] => format_to!(buf, "let {} = ", var.name(ctx.db()).unwrap()), 955 [var] => {
956 format_to!(buf, "let {}{} = ", mut_modifier(var), var.local.name(ctx.db()).unwrap())
957 }
931 [v0, vs @ ..] => { 958 [v0, vs @ ..] => {
932 buf.push_str("let ("); 959 buf.push_str("let (");
933 format_to!(buf, "{}", v0.name(ctx.db()).unwrap()); 960 format_to!(buf, "{}{}", mut_modifier(v0), v0.local.name(ctx.db()).unwrap());
934 for var in vs { 961 for var in vs {
935 format_to!(buf, ", {}", var.name(ctx.db()).unwrap()); 962 format_to!(buf, ", {}{}", mut_modifier(var), var.local.name(ctx.db()).unwrap());
936 } 963 }
937 buf.push_str(") = "); 964 buf.push_str(") = ");
938 } 965 }
939 } 966 }
967 fn mut_modifier(var: &OutlivedLocal) -> &'static str {
968 if var.mut_usage_outside_body {
969 "mut "
970 } else {
971 ""
972 }
973 }
940 format_to!(buf, "{}", expr); 974 format_to!(buf, "{}", expr);
941 if fun.ret_ty.is_unit() 975 if fun.ret_ty.is_unit()
942 && (!fun.vars_defined_in_body_and_outlive.is_empty() || !expr.is_block_like()) 976 && (!fun.vars_defined_in_body_and_outlive.is_empty() || !expr.is_block_like())
@@ -1199,10 +1233,10 @@ fn make_body(
1199 match fun.vars_defined_in_body_and_outlive.as_slice() { 1233 match fun.vars_defined_in_body_and_outlive.as_slice() {
1200 [] => {} 1234 [] => {}
1201 [var] => { 1235 [var] => {
1202 tail_expr = Some(path_expr_from_local(ctx, *var)); 1236 tail_expr = Some(path_expr_from_local(ctx, var.local));
1203 } 1237 }
1204 vars => { 1238 vars => {
1205 let exprs = vars.iter().map(|var| path_expr_from_local(ctx, *var)); 1239 let exprs = vars.iter().map(|var| path_expr_from_local(ctx, var.local));
1206 let expr = make::expr_tuple(exprs); 1240 let expr = make::expr_tuple(exprs);
1207 tail_expr = Some(expr); 1241 tail_expr = Some(expr);
1208 } 1242 }
@@ -2111,6 +2145,30 @@ fn $0fun_name(n: i32) -> i32 {
2111 } 2145 }
2112 2146
2113 #[test] 2147 #[test]
2148 fn variable_defined_inside_and_used_after_mutably_no_ret() {
2149 check_assist(
2150 extract_function,
2151 r"
2152fn foo() {
2153 let n = 1;
2154 $0let mut k = n * n;$0
2155 k += 1;
2156}",
2157 r"
2158fn foo() {
2159 let n = 1;
2160 let mut k = fun_name(n);
2161 k += 1;
2162}
2163
2164fn $0fun_name(n: i32) -> i32 {
2165 let mut k = n * n;
2166 k
2167}",
2168 );
2169 }
2170
2171 #[test]
2114 fn two_variables_defined_inside_and_used_after_no_ret() { 2172 fn two_variables_defined_inside_and_used_after_no_ret() {
2115 check_assist( 2173 check_assist(
2116 extract_function, 2174 extract_function,
@@ -2137,6 +2195,38 @@ fn $0fun_name(n: i32) -> (i32, i32) {
2137 } 2195 }
2138 2196
2139 #[test] 2197 #[test]
2198 fn multi_variables_defined_inside_and_used_after_mutably_no_ret() {
2199 check_assist(
2200 extract_function,
2201 r"
2202fn foo() {
2203 let n = 1;
2204 $0let mut k = n * n;
2205 let mut m = k + 2;
2206 let mut o = m + 3;
2207 o += 1;$0
2208 k += o;
2209 m = 1;
2210}",
2211 r"
2212fn foo() {
2213 let n = 1;
2214 let (mut k, mut m, o) = fun_name(n);
2215 k += o;
2216 m = 1;
2217}
2218
2219fn $0fun_name(n: i32) -> (i32, i32, i32) {
2220 let mut k = n * n;
2221 let mut m = k + 2;
2222 let mut o = m + 3;
2223 o += 1;
2224 (k, m, o)
2225}",
2226 );
2227 }
2228
2229 #[test]
2140 fn nontrivial_patterns_define_variables() { 2230 fn nontrivial_patterns_define_variables() {
2141 check_assist( 2231 check_assist(
2142 extract_function, 2232 extract_function,