selfhost: nodeisstr chained-str through value-struct in call args (closes #30)

selfhost/cmd/w6c/main.combined.ww

@@ -6063,6 +6063,26 @@ fn nodeisstr(c: *cgen, n: *node) bool = {
 					};
 				};
 			};
+			// Chained dot through value-struct hops (`p.inner.s`):
+			// dotinnerstructptr above only walks *struct fields, so
+			// a value-struct chain falls through and the call-arg
+			// path then pushes only 1 word for the str instead of
+			// 2 (ptr+len), silently dropping the len half.
+			// dotchainresolve handles arbitrary depth through value
+			// struct AND `*T` root, returning the leaf fieldinfo.
+			let rootnm: str = "";
+			let rootoff: i32 = 0;
+			let totaloff: i32 = 0;
+			let lfi: *fieldinfo = nil;
+			let sdelta: i32 = -1;
+			let isglobal: bool = false;
+			let ptrroot: bool = false;
+			let ok: bool = dotchainresolve(c, n,
+			    &rootnm, &rootoff, &totaloff,
+			    &lfi, &sdelta, &isglobal, &ptrroot);
+			if (ok && sdelta < 0 && lfi != nil) {
+				return isstrtype(c, lfi.tnode);
+			};
 		};
 		return false;
 	};

selfhost/cmd/wcc/cgenutil.ww

@@ -493,6 +493,26 @@ fn nodeisstr(c: *cgen, n: *node) bool = {
 					};
 				};
 			};
+			// Chained dot through value-struct hops (`p.inner.s`):
+			// dotinnerstructptr above only walks *struct fields, so
+			// a value-struct chain falls through and the call-arg
+			// path then pushes only 1 word for the str instead of
+			// 2 (ptr+len), silently dropping the len half.
+			// dotchainresolve handles arbitrary depth through value
+			// struct AND `*T` root, returning the leaf fieldinfo.
+			let rootnm: str = "";
+			let rootoff: i32 = 0;
+			let totaloff: i32 = 0;
+			let lfi: *fieldinfo = nil;
+			let sdelta: i32 = -1;
+			let isglobal: bool = false;
+			let ptrroot: bool = false;
+			let ok: bool = dotchainresolve(c, n,
+			    &rootnm, &rootoff, &totaloff,
+			    &lfi, &sdelta, &isglobal, &ptrroot);
+			if (ok && sdelta < 0 && lfi != nil) {
+				return isstrtype(c, lfi.tnode);
+			};
 		};
 		return false;
 	};

selfhost/cmd/wwdump/main.combined.ww

@@ -6063,6 +6063,26 @@ fn nodeisstr(c: *cgen, n: *node) bool = {
 					};
 				};
 			};
+			// Chained dot through value-struct hops (`p.inner.s`):
+			// dotinnerstructptr above only walks *struct fields, so
+			// a value-struct chain falls through and the call-arg
+			// path then pushes only 1 word for the str instead of
+			// 2 (ptr+len), silently dropping the len half.
+			// dotchainresolve handles arbitrary depth through value
+			// struct AND `*T` root, returning the leaf fieldinfo.
+			let rootnm: str = "";
+			let rootoff: i32 = 0;
+			let totaloff: i32 = 0;
+			let lfi: *fieldinfo = nil;
+			let sdelta: i32 = -1;
+			let isglobal: bool = false;
+			let ptrroot: bool = false;
+			let ok: bool = dotchainresolve(c, n,
+			    &rootnm, &rootoff, &totaloff,
+			    &lfi, &sdelta, &isglobal, &ptrroot);
+			if (ok && sdelta < 0 && lfi != nil) {
+				return isstrtype(c, lfi.tnode);
+			};
 		};
 		return false;
 	};